AudioCircle
Industry Circles => Audio by Van Alstine => Topic started by: avahifi on 26 Sep 2009, 09:12 pm
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I finished building our first finished production Ultravalve vacuum tube amplifier today. It is up and running in my test system and sounding out of this world musical.
Its a pretty little thing with polished stainless steel chassis and a clear anodized faceplate with black graphics and test.
The front has a lighted power switch.
The back has premium input jacks, 5-way binding post output jacks on 3/4" centers for 4 ohm, 8 ohm, and 16 ohm taps, and a line fuse and captive 16 gauge polarized AC line cord.
The chassis top has small pin jacks for bias adjusting and the bias adjust pot controls.
It uses a 5AR4 rectifier tube, two 6U8A or 6GH8A small signal tubes, and four output tubes. We supply it with EH 6CA7 tubes but EL34 or KT77 tubes can be used too.
Power is 30 watts per channel, but you can use it where you would normally use a 100 watt solid state amplifier. It does a great job of driving my 85 dB efficient Salk HT3 speakers full range.
The audio circuits are internal to protect the user from exposed high voltages and to keep the circuits from being exposed to the output tube's heat.
We will be able to ship within six weeks now and are ready to take orders. The introductory price is $1699.
We will have photos as soon as we get the finished faceplates from our supplier, which probably with be in 3-4 weeks.
Is there a better tube amp out there? We have not heard one yet. We will be running it (actually a pair most of the time) at our display room #2002 at the Rocky Mountain Audio Fest next weekend, sharing a room with Salk Sound.
Come and listen please.
Best regards,
Frank Van Alstine
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Hi Frank,
Will an optional remote option fit in there some where?
Looking forward to the pics !!
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Congratulations, Frank.
I bet that the amp will look great.
How will the UltraValve compare sonically to the Ultimate 70?
Hope I can make it to RMAF.
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I finished building our first finished production Ultravalve vacuum tube amplifier today. It is up and running in my test system and sounding out of this world musical.
Its a pretty little thing with polished stainless steel chassis and a clear anodized faceplate with black graphics and test.
The front has a lighted power switch.
The back has premium input jacks, 5-way binding post output jacks on 3/4" centers for 4 ohm, 8 ohm, and 16 ohm taps, and a line fuse and captive 16 gauge polarized AC line cord.
The chassis top has small pin jacks for bias adjusting and the bias adjust pot controls.
It uses a 5AR4 rectifier tube, two 6U8A or 6GH8A small signal tubes, and four output tubes. We supply it with EH 6CA7 tubes but EL34 or KT77 tubes can be used too.
Power is 30 watts per channel, but you can use it where you would normally use a 100 watt solid state amplifier. It does a great job of driving my 85 dB efficient Salk HT3 speakers full range.
The audio circuits are internal to protect the user from exposed high voltages and to keep the circuits from being exposed to the output tube's heat.
We will be able to ship within six weeks now and are ready to take orders. The introductory price is $1699.
We will have photos as soon as we get the finished faceplates from our supplier, which probably with be in 3-4 weeks.
Is there a better tube amp out there? We have not heard one yet. We will be running it (actually a pair most of the time) at our display room #2002 at the Rocky Mountain Audio Fest next weekend, sharing a room with Salk Sound.
Come and listen please.
Best regards,
Frank Van Alstine
Frank, if I remember correctly the power rating was expected to be 40 W rather than 30 W. Also, now the amp is cheaper than the expected price :thumb:. Just curious what changes were made. Thanks a lot and good luck with Ultravalve!
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Great news -- any pictures? More importantly, is there any chance of a monoblock version, so a phase inverter would not be necessary to use two Ultravalves as mono amps?
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Well done Frank & Co. Am looking forward to the pics. Hope you Jim & all have a great time at RMAF. :thumb:
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Monoblocks with the same power as standard Ultravalve amps bridged would cost much more than two UV amps and the Insight bridge, and you would need a fork lift truck to move them around. Cost and weight of vacuum tube amps scales up drastically with efforts to increase power.
Regarding the power rating, it all depends upon the power transformer we use.
Right now we are getting excellent new iron from Dynakitparts. Remember that power is a voltage squared function. The output voltage with the Dynakitparts power transformer gives us about 21.5V peak, with the Triode power transformer about 24V peak. That 3.5V difference is not significant in using the amp in your system, but because of the V squared function, it makes nearly a 10 watt advertised power difference.
Note that in the case of the Ultravalve amp, it works great in applications where you think you would need a 100 watt per channel amp. It drives my 85dB efficient SalkHT3 speakers just fine from top to bottom at rational listening levels and is more than enough for 87dB efficient speakers and up.
Regards,
Frank Van Alstine
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Sounds like a cool amp, can't wait to see a picture.
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There is a pic on The Absolute Sound website-HP said it was the best deal at the show...
http://www.avguide.com/blog/the-greatest-bargain-the-rocky-mountain-audio-fest
Regards,
Hoosierdaddy
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I'm not usually into the whole "shootout" thing, but there just seem so many similarities for me not to be curious how the Ultravalve amp stacks up against Roger Modjeski's RM10. Both are designed and built by manufacturers renowned for their engineering excellence; both amps' designers are extremely enthusiastic about their amplifier's abilities; both deliver around 30w/channel; both seem capable of hitting well above their weight class (Roger uses a pair of his RM10s to drive his electrostats, and Frank used a pair of his to drive the "beasts" at RMAF). I think they even have similar price tags. I'm sure they're two fantastic amplifiers.
Chad
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I'm currently using an Insight 240 amp driving my Salk Songtowers (RT version). I've been wanting to try tubes for some time now and from what I hear described, I think I'd like it. Would the Ultravalve be a good match for my STs over my Insight 240? (supplemental gear can be seen in my sig).
Thanks,
Mike
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The Ultravalve amp will work great with your Songtowers. This is the combination that the editor in chief of The Absolute Sound rated as the best value at the recent RMAF show.
However, what you will hear will be very dependent upon the musicality of your preamplifier too. I am not familiar with the one you now use.
Regards,
Frank Van Alstine
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thanks Frank. A new preamp is a little further down the line. With the Ultravalve, do you recommend your solid state or tube preamps?
The Ultravalve amp will work great with your Songtowers. This is the combination that the editor in chief of The Absolute Sound rated as the best value at the recent RMAF show.
However, what you will hear will be very dependent upon the musicality of your preamplifier too. I am not familiar with the one you now use.
Regards,
Frank Van Alstine
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All 3 of his preamps are very good but ss pre-->tube amp is pretty hot. aa
Oneinthepipe can probably share his experience with you too, having the HT2's and Wayne has one of all of Franks products. :lol: Come to think of it, OITP just about does too. :rotflmao: :rotflmao:
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I have been using the T8 DAC->Insight SL preamp-> U70 for the past two days. Tube DAC, solid state preamp, tube amp. I also like the Insight DAC->T8 preamp->Insight 440. Solid state DAC, tube preamp, solid state amp. The Insight DAC->T8 preamp->U70 is also very good. I like those combinations better than the two combinations with the T8DAC->T8preamp->either amp. This is with the 6CG7 tubes, however, where there seems to be more low end energy and less high end energy, in my room with my system, and others experiences or preferences might be different.
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How will the UltraValve compare sonically to the Ultimate 70?
Can anyone answer this?
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Frank seems to have answered the UV/U70 comparison question, just not in a verbose manner:
Is there a better tube amp out there? We have not heard one yet.
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This has been a very good read,, I am quite taken with the philisophy,,in my own words,,keep it simple,with that said,does anyone know what source/dac and pre was used in this system? Thanks in advance---and hey--Both of these gentlemen will talk with you on the phone---that tells me something right there.Frank and Jim,, a big "tip" of the hat to you,,Sirs. :thumb:
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If the U70 has not been upgraded, the Ultravalve will kick it's butt. More bass, more space, transients seem faster too. I drive my proto-type with my Insight+ EC pre and the combination is magical.
Wayner :D
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Who's waiting on an Ultravalve amp? I'll be curious to know what you think...
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Who's waiting on an Ultravalve amp? I'll be curious to know what you think...
Me too.
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Can the U70 be upgraded to the UV specs? Sonically speaking.
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Who's waiting on an Ultravalve amp?
nobody?
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I don't believe the U70 can be economically upgraded to the Ultravalve. The board for the Ultra is component side down with a closed chassis. The layout of all the inputs and outputs have been put on the back the amp. I will ask Frank to address this issue next week.
I don't know if this counts, but I am waiting for the faceplates to come back from the finisher so I can build my own.
Happy Holidays
Regards,
Dean
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I don't know if this counts, but I am waiting for the faceplates to come back from the finisher so I can build my own.
Happy Holidays
Regards,
Dean
So this amp can be bought in kit form?
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Not yet. I have recommended that a kit of some type be made available. The jury is still out.
I am one of Frank's techs, so they are all kits to me.
Regards,
Dean
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Sorry, I don't think a kit is on the table. Dean is an employee of AVA so he gets to do fun stuff that others simply can't.
Wayner :xmas:
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We will be running it (actually a pair most of the time) at our display room #2002 at the Rocky Mountain Audio Fest next weekend, sharing a room with Salk Sound.
Come and listen please.
Best regards,
Frank Van Alstine
Was this being done with an AVA bridge then?
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Yes it was. So the bridge turned them into mono-blocks with 60 watts a side, or so.
Wayner :xmas:
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Yes it was. So the bridge turned them into mono-blocks with 60 watts a side, or so.
Wayner :xmas:
Nice. So would that be equivalent to ~200w SS amps?
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I am one of Frank's techs, so they are all kits to me.
Regards,
Dean
Oh that makes sense...I had no idea that AVA multiple employees.
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Yes it was. So the bridge turned them into mono-blocks with 60 watts a side, or so.
Wayner :xmas:
Nice. So would that be equivalent to ~200w SS amps?
The amplifier in it's normal 2 channel mode is about 35 watts per channel, RMS. When used with the Phase Inverter, it turns the amplifier into a mono amplifier, summing up the 2 channels into 70 watts RMS (mono). So If you have 2 amplifiers, that would be 70 per channel or 140 total, not 200w.
Wayner :xmas:
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that would be 70 per channel or 140 total, not 200w.
Wayner :xmas:
Yes, but for the same power output using a SS amp it wouldn't be 200w? Frank posted above that it's (35w) what you would use where you would use a 100W SS amp. WIth the bridge you wouldn't double it?
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that would be 70 per channel or 140 total, not 200w.
Wayner :xmas:
Yes, but for the same power output using a SS amp it wouldn't be 200w? Frank posted above that it's (35w) what you would use where you would use a 100W SS amp. WIth the bridge you wouldn't double it?
Yes, I think that would be the effect. A pair of UltraValves with a phase inverter bridge in mono will produce 70 watts per side, but the amps will perform, subjectively, much beyond their measured power. However, I am not certain whether or not the bridged UltraValves should be used to drive 4 ohm loads, if you were thinking about these to drive the HT2-TL.
Regardless, if you were thinking about the phase inverter bridge, Frank can build the phase inverter into a new Insight preamp as an option for $199.00, IIRC.
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Yes it was. So the bridge turned them into mono-blocks with 60 watts a side, or so.
Wayner :xmas:
Nice. So would that be equivalent to ~200w SS amps?
The amplifier in it's normal 2 channel mode is about 35 watts per channel, RMS. When used with the Phase Inverter, it turns the amplifier into a mono amplifier, summing up the 2 channels into 70 watts RMS (mono). So If you have 2 amplifiers, that would be 70 per channel or 140 total, not 200w.
Wayner :xmas:
Is that correct? Frank's website description states: This sums the voltage swing of the two channels, at least triples the power, and eliminates common mode distortion. Separation, imaging, and dynamics are improved. There is no better way to get such extraordinarily high power. I seem to recall past discussions of bridged Ultra 550s being 1 kW systems, too. That wouldn't be possible if the wattage only doubled.
Am I missing something? :dunno:
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Yes it was. So the bridge turned them into mono-blocks with 60 watts a side, or so.
Wayner :xmas:
Nice. So would that be equivalent to ~200w SS amps?
The amplifier in it's normal 2 channel mode is about 35 watts per channel, RMS. When used with the Phase Inverter, it turns the amplifier into a mono amplifier, summing up the 2 channels into 70 watts RMS (mono). So If you have 2 amplifiers, that would be 70 per channel or 140 total, not 200w.
Wayner :xmas:
Is that correct? Frank's website description states: This sums the voltage swing of the two channels, at least triples the power, and eliminates common mode distortion. Separation, imaging, and dynamics are improved. There is no better way to get such extraordinarily high power. I seem to recall past discussions of bridged Ultra 550s being 1 kW systems, too. That wouldn't be possible if the wattage only doubled.
Am I missing something? :dunno:
If I understood earlier discussions correctly, the tripling of output power is with the AVA solid state amps. The U70 and UltraValve output power is doubled when bridged with the phase inverter bridge.
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Yes, OITP is correct.
Wayner :xmas:
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If I understood earlier discussions correctly, the tripling of output power is with the AVA solid state amps. The U70 and UltraValve output power is doubled when bridged with the phase inverter bridge.
So I was correct then...
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Yep.
Wayner :xmas:
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Is that correct? Frank's website description states: This sums the voltage swing of the two channels, at least triples the power, and eliminates common mode distortion. Separation, imaging, and dynamics are improved. There is no better way to get such extraordinarily high power. I seem to recall past discussions of bridged Ultra 550s being 1 kW systems, too. That wouldn't be possible if the wattage only doubled.
Am I missing something? :dunno:
If I understood earlier discussions correctly, the tripling of output power is with the AVA solid state amps. The U70 and UltraValve output power is doubled when bridged with the phase inverter bridge.
Yes, OITP is correct.
Wayner :xmas:
I'm confused. Here is an old post regarding the Ultra Bridge, and U70 amplifiers:
We have brought back our hybrid phase inverter bridge completely modernized to Ultra standards with a new multi-stage regulated power supply, new audio circuits, and an astonishing level of performance -- it simply is so transparent it is not there at all.
We did it because the Ultimate 70 vacuum tube amplifier is soooo good, only lacking in absolute power, and we wanted to see just how useful it would be to run two Ultimate 70 amplifiers bridged, with an absolutely pure bridge - phase inverter circuit.
We did it. It works. The results are pretty magnificant. A dual mono reasonably high powered vacuum tube power set that sounds nothing at all like a big vacuum tube amplifier. Attacks and dynamics and range are oh wow startling, but no rough edges, no grain, no glare at all, just all of music, all of the emotions but no mud!
The connection is from your preamp to the left and right inputs of the Ultra Inverter, and from the left and right inverting and non-inverting outputs of the Ultra Inverter to the inputs of two stereo power amplifiers. Then the speaker wires are connect from the hot terminals of each channels (ground side terminals not used) and on to your speakers. The inverter sums the voltage swing of both channels, and since power is essentially voltage squared, the result is close to four times normal single channel power, subject to real world inefficiences of course.
Disadvantages, none except that you need two stereo power amplifiers and the Ultra bridge to make it work. The configuration is not advised for low impedance speakers as the bridge connection causes your amplifier to look at a speaker load as being one half of normal, so this is not useful with 4 ohm speakers or less.
Thanks for listening.
Frank Van Alstine
Has this changed? How does the inverter know if it's being fed tube watts or SS watts?
Sorry to go OT, but I am curious about the true output of bridged Ultravalves.
Jerry
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Well I have the same question as Jerry. But the phase inverter is not feed the power of the amps, it is placed between the preamp and power amps. I have heard AVA say about 4 times the power with a phase inverter,also 3 times and now 2X with the U70 or UltraValve. Just curious I guess.
But... what difference does it make as long as the system has enough power to satisfy your needs.
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It's not the inverter "knowing" anything, it's just how the Ultravalve behaves when put into this configuration. The power is simply the sum of the two channels. I believe this is because of the output transformers. The hybrid and SS will tripple their power.
Wayner :xmas:
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Just going to say that I am sure that the Ultravalve is a wonderful sounding amp and probably COULD sound better than the current iteration of the U70 (since the free little mod). However, I am so happy with my U70 that I don't think I would want to go through much effort to try to top it. Easiest thing to do would be to sell your U70 and buy an Ultravalve.
Me, I am going to keep my U70 and just enjoy it. After several months of performing the "upgrade" it still can AMAZE me....
Note, I have not heard the ultravalve and am just expressing a useless opinion.
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Again,
We were running two Ultravalves at RMAF in this configuration and powering Jim Salk's new HT-4s with tremendous results. I too, thought the power would tripple, but Frank corrected me on this and pointed out the output trasnformers. 2 Ultravales with almost any speaker would be impressive.
Wayner :xmas:
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The "catch" when bridging vacuum tube amplifiers is that you need to go down to the next lower output transformer matching tap for correct impedance matching to the speaker. A 16 ohm speaker looks like an 8 ohm load to a bridged amp, an 8 ohm speaker a 4 ohm load and so on.
With solid state amplifiers with very low output impedances there is no multiple output taps, one source drives anything within the current limits of the amplifier.
With vacuum tube amplifiers you need to match impedances as mentioned above. And each lower output tap puts out a higher output current but less output voltage than the higher impedance taps. So when you bridge vacuum tube amps, you do not double the output voltage and thus quadruple the bridged single power rating, you only double the power rating. V remains the same, but R is cut in half and V squared over R only yields X2 power instead of X4.
Got it?
However, X2 power and X2 current into that load is still provides a very healthy bridged amp into difficult loads.
Regards,
Frank (just back from being snowed in, very happily, in the Wisconsin North Woods for three days watching the deer play in the yard).
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V remains the same, but R is cut in half and V squared over R only yields X2 power instead of X4.
Got it?
Yep; perfectly. :thumb:
Thanks, Frank. I appreciate it.
Jerry
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Can the U70 be upgraded to the UV specs? Sonically speaking.
I talked to Frank and he confirmed that the U70 can not be upgraded to the Ultra Valve for the reasons stated in my previous response.
Regards,
Dean
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I talked to Frank and he confirmed that the U70 can not be upgraded to the Ultra Valve for the reasons stated in my previous response.
But can you tell us why other than the Ultravalve has a closed chassis, and the board is upside down? So far no one has really answered this question. I want circuit description, and theory of operaton between the two.
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I would rather not talk about theory of operation in detail at this time. Like to get a substantial number sold out there before our ideas star getting copied again.
Regards,
Frank Van Alstine
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Got it, and I fully respect that, Frank.
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Finally, our new Ultravalve faceplates showed up here so we are ready to build and ship this new pure vacuum tube amplifier.
Be the first on your block to own one. $1699 and just amazing musical performance.
Regards,
Frank Van Alstine
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Looking forward to the updated website.
Regards,
Peter
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By the way, the new Ultravalve chassis is highly polished stainless steel using all truss head stainless philips hardware.
The new faceplate is a matt finished light gold with black text and graphics.
It is really pretty.
Frank Van Alstine
We will try and get photos done of it, and the Vision DAC and AvaStar preamp as soon as possible.
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My new Ultravalve is here!!!!!!!!!!!!!!!!!
(http://www.audiocircle.com/image.php?id=26898)
(http://www.audiocircle.com/image.php?id=26897)
(http://www.audiocircle.com/image.php?id=26899)
(http://www.audiocircle.com/image.php?id=26896)
Wayner :drool:
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Very Nice Wayner, Smooth, fit and clean looking. I really like the faceplate.
Harrison
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Light that firecracker up Wayner, then snap a picture please. :lol:
Cheers,
Robin
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Congrats Wayner.
Nicely done Frank.
George
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Beautiful work, Frank, Wayner, et al.
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Some interior shots please! :)
Roy
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Some interior shots please! :)
Roy
Let him light her up 1st! :drool: (w/ camera in hand) :lol:
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(http://www.audiocircle.com/image.php?id=26906)
Lets give credit where credit is due, Larry Jenkins is the amp builder and he did the superb job on this one. I just draw the stupid pictures, these guys make the stuff happen. Once again I am reminded by myself, how lowly I am, and how wonderful the rest of the group is. Thanks Larry and Frank.
Wayner
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LUCKYYY!!! :drool: with most all the changes I dreamnt of :inlove: Frank is the man. :green:
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Lets give credit where credit is due, Larry Jenkins is the amp builder and he did the superb job on this one. I just draw the ... pictures....
Wayner
Good drawings, Wayner. And great job, Larry and Frank.
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If Wayne didn't do his job well we couldn't do our job well. His "stupid pictures" are used by our vendors to create the chassis and faceplates. We who assemble the units appreciate the fit and finish created with his drawings.
Once our web site is updated (don't ask), there should be some pictures of the inside of Wayne's Ultravalve. Larry did a great job. I would have let him do mine except I enjoyed doing it myself too much.
Regards,
Dean
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Hi Frank,
Classy looking amplifier. I bet you will sell a bundle of them.
Regards
Rod
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By the way, the Ultravalve came plug and play. Frank and his merry men have designed a very special carton to get the amp to your house in one nice and shinny piece, with tubes on board. This is accomplished with 2 custom designed inserts to snug the transformers and put a very slight and captivating amount of "hold power" on the tubes. It's just a fantastic product! Of course, I'm biased, Fit and finish are first class.
It only took a few minutes to plug in the amp, set the initial bias to 1.6VDC (with no input), rechecking after about 15 minutes, and then it was rock and roll.
(http://www.audiocircle.com/image.php?id=26931)
Wayner
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I'm interested to see a 16 OHM speaker connection. Forgive the ignorance but what is done to make the 4 OHM different to the 8 OHM different to the 16 OHM output? Why have you chosen to add the 16 OHM connection - it seems quite unusual.
Oh, and by the way, layman's language would help a lot - I certainly fall squarely in that category :?
Cheers
Will
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Will,
Those are standard impedance taps off the transformer. Yes, the 16 Ohm is unusual, but there are some older vintage speakers out there that some folks may have and want to use with this amplifier. I think I remember some old Utah coaxial and triaxial speakers that were 16 Ohm?
Wayner :D
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The amp (and packing) is stunning. Just beautiful. :drool:
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My new Ultravalve is here!!!!!!!!!!!!!!!!!
(http://www.audiocircle.com/image.php?id=26898)
(http://www.audiocircle.com/image.php?id=26897)
(http://www.audiocircle.com/image.php?id=26899)
(http://www.audiocircle.com/image.php?id=26896)
Wayner :drool:
:drool: :drool: :drool:
Triple drool
Very tempting
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:drool: If I ever do a major house move or room change that my Mk IV's won't work in THIS IS THE AMP I would snatch up in a second. 8)
As for 16 ohm taps my Dad's Altec Voice of the Theator horn and woofer speakers run off the 16 ohm taps of his Marantz 8b. All I can say is :thumb:
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Today I finished designing and ordered parts for my new Ultravalve dual DC voltage LCD meter. This is a little DIY project I have had in mind for some time. It will read the bias voltage of the left and right channels at the same time and allow me to dial it in, instead of fartin' around with my VOMs. The LCD meters are from Velleman and require a 9 VDC power source, which I will use a wall wart with plug and receptacle. The test lead probes will fit into the banana jacks on the unit and (with some modifications) will fit into the probe jacks on the Ultravalve. Should be a fun little project.
(http://www.audiocircle.com/image.php?id=27084)
Wayner :D
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I can't find this amp in avahifi.com. Any idea about pricing.. availability...?
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$1699, available now.
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Way neat Wayner. :thumb:
And congrats on the awesome amp!!!
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I can't find this amp in avahifi.com. Any idea about pricing.. availability...?
avahifi-how to order- price list (new).pdf
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Today I finished designing and ordered parts for my new Ultravalve dual DC voltage LCD meter. This is a little DIY project I have had in mind for some time. It will read the bias voltage of the left and right channels at the same time and allow me to dial it in, instead of fartin' around with my VOMs. The LCD meters are from Velleman and require a 9 VDC power source, which I will use a wall wart with plug and receptacle. The test lead probes will fit into the banana jacks on the unit and (with some modifications) will fit into the probe jacks on the Ultravalve. Should be a fun little project.
Wayner :D
So this amp does not auto-bias? I thought it did but perhaps I was mistaken.
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So who else thinks that the black faceplate screws should be replaced with chrome hex-head bolts? If I had one of these amps that'd be the first mod. The gold-plated transformer bells could wait a few days. :)
Nice meter project Wayner! One of my small laments is that when Frank was asking us what we'd like to see in the new tube amp, no one 'put in for' individual bias pots for each tube. If we'd gotten it, your meter would have four (or even six) meters! :eyebrows:
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So who else thinks that the black faceplate screws should be replaced with chrome hex-head bolts? If I had one of these amps that'd be the first mod.
+1. That was my first thought when I saw the picture of this beautiful amp.
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So who else thinks that the black faceplate screws should be replaced with chrome hex-head bolts?
I was thinking satin stainless steel hex screws.
Steve
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I like the screws in the faceplate. That tells you it's a real Van Alstine. :eyebrows:
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Now you guys have me looking at the screws on the T8 faceplate...Hmmm :eyebrows:
Wayne I like the bias meters idea. Will these be left on or switched on only when checking the bias with no signal present?
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Wayne I like the bias meters idea. Will these be left on or switched on only when checking the bias with no signal present?
I had planned on leaving them on all the time, maybe I should ask Frank if that's OK.
Wayner :D
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Assuming that the input to your meters is high impedance, leaving them connected should not harm anything.
However, note that the bias voltage reading will go much higher as the amp is driven harder, more than doubling. So make sure the working range of the meter circuit can accommodate this.
Regards,
Frank Van Alstine
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100M ohm input impedance.
Wayner
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Very nice update Brian.
It really is the kind of amp you buy and then find good speakers for
I read a comment such as that and want to start building a second system. 8)
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the kind of amp you buy and then find good speakers for
such as?
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To me the best match is something pretty efficient. Even better would be one of those speakers that incorporate a powered subwoofer. I have a pair of Infinity IM4.1. this is my match made in heaven. I have no issues with volume, they play louder in my room than I can stand. the u70 sounds absolutely fantastic with them. You can find them sometimes at a very good price. These are the last of the big time Infinities in my mind and they really sound fantastic. I have seen them used for as little as $1500 a pair and the matching center and im2.6 for rears can be picked up at a bargain price as well for a home theater set up that can't be beat. I guess they never got the reviews to make them really popular on the used market but I love my pair and an excellent match with the u70. Probably the Mythos would be a good match as well.
Another good match would probably be a sat sub set up where you would be able to cross over the u70 at 80 hz. In my case I run the IM4.1 full range and also have a pair of VMPS subs. I get great pleasure in thinking that I have 35 watt a channel for the fronts and 2200 watts for the subs. 850 per speaker and another 500 for the subs.
"Insert evil laugh here"
I have true "bass lock" in my room but Phil Lesh deserves the best, don't you think?
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Can you run KT-77's in place of EL34's in Ultravalve amp? I assume the bias would have to be set slightly higher.
NB
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Yes, you can use KT77 tubes in the Ultravalve amplifier. I tried a set here, same bias setting as normal. One problem was the JJs I got had smaller pin diameters than normal so they were an "iffy" loose fit into the tube sockets which I did not like so they came back out pretty quickly even though they sounded just fine, but no better than our normal tubes here.
Regards,
Frank Van Alstine
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Frank, thank you for the quick reply. I have been very pleased with Genalex Gold Lion (New Sensor) reissued EL84 tubes in my current amplifier and wanted to see if KT77's were a viable option. Now I just have to figure a way to convince my wife I need an UltraValve amp :lol: :lol: :lol: :lol:
I am working on it.
NB
Yes, you can use KT77 tubes in the Ultravalve amplifier. I tried a set here, same bias setting as normal. One problem was the JJs I got had smaller pin diameters than normal so they were an "iffy" loose fit into the tube sockets which I did not like so they came back out pretty quickly even though they sounded just fine, but no better than our normal tubes here.
Regards,
Frank Van Alstine
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Ah, that is where the saying came from "I asked God for a new bicycle and it never came, so I stole one and asked for forgiveness."
Wayner :eyebrows:
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I have to disagree about efficiency a little bit. I mean, really, the strength of the U70 is not "the vise like grip on the bottom end" like you would get with a big Krell or something like that. I admit to having some youthful tendencies when it comes to the bottom end. If you can take 80hz on down and take it away from the U70 you get the best of all worlds. But I do agree, the U70 has plenty of power for most applications, just ease up the requirements for current. A sub/sat system or a speaker system with a powered bass system will do that just fine.
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My project for the Ultravalve is almost complete, needing a missing add-on (resistors) that will change the reading level from <200mv to 20 volts. They are metal film resistors that are 1/2 watt, .1% tolerance, and not available at Rat Shack. The good news is that AVA is a Velleman dealer and could get the kits thru Frank (Dean was the help on this one, thanks!). Anyway, apart from that, all has gone fairly well and it will free up my 2 other VOMs. I decided to put into service a 9 volt wall wart, and have that power supply switchable, and I also decided to switch out the bias test points from the Ultravalve, so that they are not connected all of the time. When the project is complete (and successful), I will publish a bill of materials and some drawings if anyone is interested in this kind of a DIY project. Total cost is about $50, so you might be better off buying 2 VOMs, but this is more compact and not battery operated.
(http://www.audiocircle.com/image.php?id=27321)
(http://www.audiocircle.com/image.php?id=27322)
Wish me luck!
Wayner :D
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Wayner,
I'm definitely interested!! :drool:
Looks very nice.
Ron
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In another thread somebody talks about how big a difference the rectifier tube makes in the sound of the U70. Any thoughts on this?
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Lookin' good so far. :thumb:
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Wayner,
Would those two meters be the PMLCDL model?
Thanks,
Ron
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wayner,
needing a missing add-on (resistors) that will change the reading level from <200mv to 20 volts.
Of course you could change the bias set resistor on the UltraValve to precision 1.0 ohm units and use the meter as is with the 200mv full scale range. You would then set the bias to 100.0mv on the meter.
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Wayner,
Would those two meters be the PMLCDL model?
Thanks,
Ron
Yep. Frank is helping out. The one thing I will not do is alter the Ultravalve. It stays original.
Wayner :D
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Hello
Are we still at $1699 for these?
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Hello
Are we still at $1699 for these?
Yes. The current AVA price list for new equipment can be seen here (http://www.avahifi.com/root/ordering_info/price.htm).
Have fun,
Jerry
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Meters are up and running!
I've been on the stump, trying to find some resistors in town. Living in a small town makes it hard to find a 9.90 megohm resistors, but I got the mission accomplished. To get the meters to read the proper range, resistor RB needed to be taken out and replaced with a 9.90megohm resistor, which I made from 2 4.7M and 5 100Ks. Then RA needs to have a 100K ohm resistor in parallel with the existing resistor. The manual says to use .1%, I used 5% and got the values that I wanted.
Here are a couple of photos of the guts and the unit working. I put in a power switch and LED for power, another switch to take the hot lead off the Ultravalve bias pots and I even put in a power receptacle in case I want to put a 10 gauge power cord to it from my 9 volt, 500ma wall wart!
(http://www.audiocircle.com/image.php?id=27573)
(http://www.audiocircle.com/image.php?id=27574)
Here is a bill of materials if any of you would like to build one:
(2) Test lead sets Parts Express #390-120
(1) 2.5mm Panel Mt DC Jack Parts Express #090-479 (this may change depending on wall wart)
(1) 9 volt wall wart (go to Radio Shack and get one) Parts Express measured 14.6 volts
(2) Dual binding post Parts Express #090-475
(2) Velleman meters Parts Express #320-241
(1) Box Radio Shack size: 6 X 4 X 2
You will need to cut a couple of rectagular holes for the meters as they need that to mount (snap in).
(2) 100K 1/4 watt 5% resistors
(2) 9.90M 1/4 watt 5% resistors (or (4) 4.7M + (10) 100K ohm resistors (as I had to do).
If you build the resistor series network, get a couple of breadboards (Radio Shack #276-148).
(4) rubber stick on feet (Radio Shack #64-2342, pkg of 8)
(2) Double pole, double throw switches.
(1) Red Led, 2 volt, 20ma.
(1) LED panel mount escutcheon.
(2) Feet of Cat-5e wire (stripped and untwisted) to make interconnect wire.
I will make a schematic later.
Also notice the wiring. That is exactly why Frank has me do mechanical. :lol:
Wayner :D
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Very cool Wayner. :thumb:
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Here is the schematic. Sorry about the ladder logic.
(http://www.audiocircle.com/image.php?id=27583)
Wayner :D
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My tax returns are done, nice refund coming and my wonderful wife has endorsed my purchase. She puts up with quite a lot from me. An Ultravalve 70 is in my future, after I get my check from Uncle. Yahoo!
NB
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Good move! :D
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If anyone is interested, I did a little bias voltage study this weekend and here are the results:
1.7[/t][/t] 1.68[/t] 1.66[/t] 1.65[/t] 1.63[/t] 1.62[/t] 1.61[/t] 1.61[/t] 1.6[/t] 1.6[/t] 1.6[/t] 1.59[/t]
The message here is that it doesn't pay to fool around with the bias until the amp has been on for at least 1 1/2 hours. This behavior seems to repeat daily and the bias start voltage is almost always at about 1.70 VDC.
Wayner :D
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Wayne, I have no idea if those are significant differences but does the amp sound any different at 1.7 and 1.59?
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No, I can't tell any difference, tho I'm not playing a single test tone (just music) and I perceive no change. That is not a big swing, anyway. I thought it might help those that maybe constant twiddlers that messing with the bias settings really isn't necessary. I'd think if you checked it once or twice a week, you would be more then fine.
I was interested in the bias voltage behavior, and my dual meter box really helped me to understand the amp better and how the bias behaves. I was fiddling with the bias all the time and have now learned that it really isn't necessary. Like I stated before, let the amp run for about an hour and a half, and check (and set) bias. The behavior of the bias voltage seems repeat, telling me first, that my line voltage is very stable, and second, the amp is very stable.
Wayner :D
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Finally looked at AVA price list. Quite impressive for what you get. Very fair and reasonable. Kudos to all concerned. Refreshing actually. 8)
charles
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Thanks Wayne. :D
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Just ordered an Ultravalve from Frank yesterday. It will be replacing my AVA Insight 240 (slim chassis) and will be paired with my AVA T8+ (which I love).
Can't wait! :thumb:
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Just ordered an Ultravalve from Frank yesterday. It will be replacing my AVA Insight 240 (slim chassis) and will be paired with my AVA T8+ (which I love).
Can't wait! :thumb:
Great news , dying to hear your opinions with the Songtowers
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Just ordered an Ultravalve from Frank yesterday. It will be replacing my AVA Insight 240 (slim chassis) and will be paired with my AVA T8+ (which I love).
Can't wait! :thumb:
Now all you need to do is replace that PS Audio DAC with a AVA Vision Dac and let the light shine in. 8)
Don't forget the pictures. :D
Cheers,
Robin
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Now all you need to do is replace that PS Audio DAC with a AVA Vision Dac and let the light shine in. 8)
Don't forget the pictures. :D
Cheers,
Robin
I'm actually not using the PS Audio DAC. I let a friend borrow it. My source for digital is strictly my Oppo SE which I LOVE. As for DACs, I've been considering one if Frank's DACs to go with my upcoming Squeezebox Touch but also very interested in checking out the Wyred4Sound DAC-1 which uses the ESS Sabre like the Oppo SE. No word yet on release on it.
For now, just excited to get the Ultravalve. I've moved in the last week and loving my new room. The UV will be very happy. :)
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My tax returns are done, nice refund coming and my wonderful wife has endorsed my purchase. She puts up with quite a lot from me. An Ultravalve 70 is in my future, after I get my check from Uncle. Yahoo!
NB
The refund check watch has begun. Frank has been most helpful and I can't wait to place my order. Even my good friend Gordy, who helped my Felix power conditioner build, is waiting for a listen.
NB
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My good friend Gordy, who helped my Felix power conditioner build, is waiting for a listen.
NB
Good to hear that Gordy is fine. I hadn't seen any posts from him recently. He was very helpful to me when I had a problem with a DVP with a noisy power supply. His generosity was astonishing. He seems extremely knowledgeable, too.
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The refund check watch has begun. Frank has been most helpful and I can't wait to place my order. Even my good friend Gordy, who helped my Felix power conditioner build, is waiting for a listen.
NB
I was just asking Chris (Lonewolf) last night what happened go Gordy and how he was doing. I'm glad to hear all is fine. I always wanted to meet Gordy at a NY RAVE. He is a tweakmaster IMHO. :D
Cheers,
Robin
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BTW, Gordy is doing fine, he is still recovering from a health issue that knocked him back a bit last year. I'll be sure to convey your best from his many AC friends.
NB
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The "catch" when bridging vacuum tube amplifiers is that you need to go down to the next lower output transformer matching tap for correct impedance matching to the speaker. A 16 ohm speaker looks like an 8 ohm load to a bridged amp, an 8 ohm speaker a 4 ohm load and so on.
Does this mean I would not be able to bridge the Ultravalve with my speakers, since they are 4 ohm and the Ultravalve does not have a 2 ohm tabs ?
Also is there no way to use the Ultravalve as a monoblock by combining its stereo outputs to one channel?
Thanks
Harrison
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Probably too low. However, unless you listen to your music at crushing volumes, there is still plenty of power with a single amp. I currently have my Ultravalve running my Dyanco A25XL mods and there is more then enough power. Great with vinyl.
Wayner :D
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When I run my Songtowers (4 ohm load) with my two U70s (similar to Ultravalve) via an AVA phase inverter, I use a pair of Speltz Zeroformers set at X2 or X3 to end up with an effective load of 4 ohms or 6 ohms and use the amp's 4 ohm outputs. It seems to work fine. I have also forgotten and run them bridged without the Zeroformers for a short period with no damage. Ask Frank what he thinks.
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The drawback to not matching amplifier impedance to the speaker load is that the load acts as a voltage divider. For example using the 4 ohm tap into a two ohm load will cut the voltage output of the amp in half. Or, you are now back to the same power level that you would have had by just using one amp not bridged. A huge waste of resources. It won't hurt the amp, but you will gain nothing in power trying to drive low impedance loads with bridged vacuum tube amplifiers.
Regards,
Frank Van Alstine
P.S. The Speltz Zeroformers might be a solution. I would appreciate a link to them.
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Frank,
Don't know how to post a link. The email address is www.zeroimpedance.com (located somewhere in St.Paul).
I guess I know how now!
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I just bugged Paul to see if I can play with a loaner set of his 2X impedance matchers over a weekend soon. They might allow bridging a pair of Ultravalve amps into a low impedance speakers for really really nice results.
I will let you know how this proceeds.
Frank Van Alstine
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The Dyna output transformers only have 4, 8, and 16 ohm outputs as we all know. The 16 ohm tap represents 100% of the secondary. The 8 ohm tap represents 70.7% of the secondary. The 4 ohm tap represents 50% of the secondary. Now if there were a 2 ohm tap, that would be 25% of the secondary. This is where one would want to connect a 4 ohm load (speaker) on a bridged amp, between the two 2 ohm taps in order to provide a 4 ohm load across the two transformers with respect to ground.
An alternative is to disconnect the C or 0 ohm tap from ground and instead, connect the 4 ohm tap to ground. You would then connect a 4 ohm speaker between the two 8 ohm taps. While the winding count isn't quite at 25% between the 8 ohm and 4 ohm (ground) it is 20.7% which is much closer to 4 ohms than connecting the speaker between the two 4 ohm taps.
Now this will change the feedback voltage by half since you are now supplying the feedback voltage from the center tap (4 ohm) and the 16 ohm tap. Changing the feedback resistor from 1 K ohm to a 499 ohm resistor will get the gain back where it was. You could just as easily add a second 1 k ohm resistor in parallel to achieve the same results.
I realize that this may be beyond most listeners abilities. Those who have built the Dynakits or have done Frank's Super 70i or Ultra 70 rebuilds should have no problem. As for the UltraValve, I'm guessing the same can be done. Since most users may wish to to use 4 ohm speakers and want an UltraValve, I'm sure Frank or one of his folks could perform the change, test on the bench and report back. He may be able to configure an UltraValve in this matter for 4 ohm speaker use. Seems a more economical solution than spending $450-$950 for matching transformers. Just move one wire and add/change one resistor per channel.
Thanks,
Ron
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Way to think out of the box, Ron. If you are not bridging two amps and you just needed to drive a 2 ohm speaker, you could connect it between the 4 and 8 ohm taps without any other mods. I don't know how many 2 ohm speakers there are out there, so this would probably only apply if you were paralleling several 8 ohm speakers.
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The following is a response I just wrote to an AC viewer interested in our Ultravalve amplifier. He asked if he could substitute some "designer type" capacitors in the Ultravalve amp for perhaps better sound.
I would like comments as to your opinions if my response was fair and appropriate.
Thanks,
Frank Van Alstine
Whoops, an error on my part. The interstage coupling capacitors are 2.2uF at 400V not 250V.
First of all, there are no output coupling caps in the Ultravalve amplifer, the output is transformer coupled, as is most pure vacuum tube equipment.
I am doubtful if your Mundorf "silver oil" capacitors will be appropriate for this application. I suspect they are polarized capacitors (have a marked plus and minus end).
In any event, the capacitor values we use in input and interstage applications are 8 x 2.2uF at 250V film interstage couplers and 2 x .047uF 50V film input couplers. Both are non-polar film types and the absolute values must be matched to within 1 percent. That means you must have a large supply of capacitors and a precision capacitor meter to make matched pairs.
Also, our PC card is laid out for the dimensions of these parts and shoehorning in something larger will result in excess lead inductance and likely unanticipated underdamped resonances.
What are the physical dimensions of the parts you are interested in?
Let me know. and if we can determine by their electrical specifications (sounds just wonderful is not a specification) and if they are the proper physical size to fit the board, and if you can supply enough of them so we have an adequate population to install matched sets, then you would be much better off having us do the installation in the first place.
We would not charge you extra for this service.
However, of course that would make the unit a "custom" one off piece and it would be necessary for you to wave the satisfaction guarantee on the purchase.
Best regards,
Frank Van Alstine
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Frank,
Quite fair and appropriate. Not owning an UltraValve, but instead two U70's, I think the 2.2uF interstage couplers are in fact 400 Vdc units.
Ron
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The following is a response I just wrote to an AC viewer interested in our Ultravalve amplifier. He asked if he could substitute some "designer type" capacitors in the Ultravalve amp for perhaps better sound.
I would like comments as to your opinions if my response was fair and appropriate.
Thanks,
Frank Van Alstine
Certainly reasonable and sensible. But I can guess why you are asking...
Brett
p.s. in fact, I bet this is the part that caused the problem:
"Let me know. and if we can determine by their electrical specifications (sounds just wonderful is not a specification) and if they are the proper physical size to fit the board, and if you can supply enough of them so we have an adequate population to install matched sets, then you would be much better off having us do the installation in the first place."
Not inaccurate but some people are not big fans of reality. And for their capacity, they are HUGE.
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Sounds most accomodating and reasonable to me.
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Next week is going to be a good week and April in general is going to be 'da bomb'. Frank shipped my Ultravalve today and set to arrive next Monday. Got my preorder in for the Wyred4Sound Dac-1(expected next week as well). Also this month getting my acoustic treatments from GIK. Recently moved into a new house and waiting for it to all come together before getting final pictures.
And to top it all off, I'm flying to Detroit for AK Fest on the 30th to hang with some good friends and check out killer gear. What a great month. Thanks April! :thumb:
...And Frank. You sir started my wonderful month this morning with the UPS notification. I salute you. :drool:
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Next week is going to be a good week and April in general is going to be 'da bomb'. Frank shipped my Ultravalve today and set to arrive next Monday. Got my preorder in for the Wyred4Sound Dac-1(expected next week as well). Also this month getting my acoustic treatments from GIK. Recently moved into a new house and waiting for it to all come together before getting final pictures.
And to top it all off, I'm flying to Detroit for AK Fest on the 30th to hang with some good friends and check out killer gear. What a great month. Thanks April! :thumb:
...And Frank. You sir started my wonderful month this morning with the UPS notification. I salute you. :drool:
LUCKY!
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I just bugged Paul to see if I can play with a loaner set of his 2X impedance matchers over a weekend soon. They might allow bridging a pair of Ultravalve amps into a low impedance speakers for really really nice results.
I will let you know how this proceeds.
Frank Van Alstine
Have you had a chance to try the zero's?
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Bump--I'd like to know about the zeroformers as well...
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Okie Dokie,
I just got off the phone with Frank and asked his 'elves' to build me an UltraValve Amp.. I never thought I would go back to TUBES ever!!
Solid State rules! No stinking bias adjustments etc...oh well I guess we all can change..after all its all about the music isnt it?
:eyebrows:
No what to do for a preamp?
Alex
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Bump--I'd like to know about the zeroformers as well...
http://www.zeroimpedance.com/Zero-New.html
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Can this amp be fitted with IEC socket instead of hard-wried power cord? Thanks.
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:)
The topic "IEC receptacles on AVA amps" was moved to the Intergalatic Wastebin several months ago. Happy reading!
http://www.audiocircle.com/index.php?topic=72601.0 (http://www.audiocircle.com/index.php?topic=72601.0)
Steve
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(http://www.audiocircle.com/image.php?id=26906)
I know this is a superficial question, but can someone tell me why in the picture above, the tubes don't appear to be glowing as much as the amp in this pic below ?
I see what look to be green leds, but I'm referring to the orange/blue glow of the tubes themselves. They look much brighter. Is it simply a matter of the photography ? Or because they are different varieties of tubes ? I'm a noob, never owned a tube amp or preamp before, but find them fascinating. I am especially interested in a well built, American product representing a good value such as the AVA ultravalve. TIA :D
(http://i53.tinypic.com/1604mzn.jpg)
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That is my piss poor picture with the Ultravalve under my desk, very dark area. The difference between the amps is both photographic and tube type as you guessed.
Wayner
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A tripod and a long exposure does not always make a good shot of glowing tubes. Of coarse if you "adjust" the bias to 5 times or more it's norm you can get some amazing shots. :o But that's cheating. :lol: