UltraValve Build

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rlee8394

Re: UltraValve Build
« Reply #20 on: 26 Jan 2012, 03:25 am »

rcag_ils

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Re: UltraValve Build
« Reply #21 on: 26 Jan 2012, 10:29 pm »
Thanks Ron.

PeterCapo

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Re: UltraValve Build
« Reply #22 on: 7 Feb 2012, 04:27 am »
This amp should really be offered as a kit.  I'd like to see it with individual bias adjust for each power tube.  Kevin at Dynakitparts has this for his standard (classic) Stereo 70 - perhaps it could be adapted to the UV?

Wayner

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Re: UltraValve Build
« Reply #23 on: 7 Feb 2012, 12:53 pm »
Kevin has the kits.


PeterCapo

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Re: UltraValve Build
« Reply #24 on: 7 Feb 2012, 04:43 pm »
Do you mean the kit for the individual bias adjust?  Does Kevin's bias kit drop right into the UV?

ClothEar

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Re: UltraValve Build
« Reply #25 on: 15 Aug 2012, 04:26 pm »
Do I see an IEC power connector ?  Finally, support for magical power cords ;-)  ;-)  ;-)
CE


avahifi

Re: UltraValve Build
« Reply #26 on: 16 Aug 2012, 02:10 pm »
Yep, all new AVA equipment is now supplied with an IEC power jack and ground lift switch to take care of possible ground loop hum issues.

Now you are welcome to spend more on your power cords that you did on the equipment itself if you want, although the power cord we supply seems to sound just fine, at least neither TAS or Enjoy the Music had any reservations about it.

Regards,

Frank Van Alstine

avahifi

Re: UltraValve Build
« Reply #27 on: 16 Aug 2012, 02:12 pm »
I doubt if Kevins' individual bias adjustment kit would be an easy install in the Ultravalve amp.  Our chassis mechanical layout was not designed for that.  We have seen no sonic issues with the way bias sets on the Ultravalve or the Ultimate 70 as is.

Regards,

Frank Van Alstine

Tom Alverson

Re: UltraValve Build
« Reply #28 on: 17 Aug 2012, 08:56 pm »
I doubt if Kevins' individual bias adjustment kit would be an easy install in the Ultravalve amp.  Our chassis mechanical layout was not designed for that.  We have seen no sonic issues with the way bias sets on the Ultravalve or the Ultimate 70 as is.

Regards,

Frank Van Alstine

Another way to look at it is that if your tubes are so poorly DC matched that you need separate DC bias adjustments, then they are probably poorly matched for AC (audio gain etc) and would not work as well as tubes that were better matched (AC and DC).

Tom

ClothEar

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Re: UltraValve Build
« Reply #29 on: 25 Sep 2012, 06:36 am »
Would the UltraValve on its own be enough to power KEF 105/3's full range 50Hz-20kHz ?  The KEF's claimed sensitivity is:

93dB at 1m 2.83V input

Funny spec. This would be 93dB 1m for 1W input for an 8ohm speaker.  The KEFs impedance is 4ohms, resistive all the way from 20Hz - 20kHz.



avahifi

Re: UltraValve Build
« Reply #30 on: 25 Sep 2012, 03:26 pm »
Our Ultravalve vacuum tube power amp has more than enough power for a 93 dB efficient speaker and it has 4, 8, and 16 ohm output taps so the 4 ohm load is not an issue either.

Note that 3 dB efficiency difference between two speakers is the same as having twice as much power for the more efficient one.  Since we rate the Ultravalve to be just fine for 87 dB efficient loads and up, its 35W/Ch is equal to 70W/Ch for a 90 dB efficient speaker, or 140W/Ch for a 93 dB efficient one.  Combine that with the interesting observation that the Ultravalve seems to play as cleanly and loudly as a typical 100W/Ch solid state amp, it will be an excellent match for your speakers even driving them full range.  Its bass control and power is pretty outstanding too.

Regards,

Frank Van Alstine

trebejo

Re: UltraValve Build
« Reply #31 on: 25 Sep 2012, 06:38 pm »
I used the U70 with a pair of Ohm 2000's and it was plenty loud enough without any noticeable strain. IMO the room size is an essential parameter, as perceived loudness is mostly a three-parameter issue (assuming standard linestage levels): speaker efficiency/sensitivity, amp wattage, and room volume. You can sit closer to your speakers and hear them louder, so psychoacoustics enters into it as well. To see if my setup is "loud enough", I go as far away as possible from the speakers and blast them a bit louder than I can stand it long term--the U70 always passed that test in the 2000 ft^3 room that I used it in and I am pretty sure that it would have passed that test in my current 5000 ft^3 room with 15" Tannoys.

The loudness-killer combo is a large room and 80something db efficient speakers that cannot take 1000's of watts (i.e. a very large percentage of "audiophile" speakers nowadays). An excellent 35-watt tube amp should be fine for daily sane usage in just about all settings, and if it isn't then the first place to look is probably at the speakers, then the amp (assuming that the room is the fixed variable).

If you want it to be as loud as it is at your favorite nightclub, then you might need to get a pair of pro speakers (say, some JBLs) which hover around 100db for 1 watt, and in that case the UltraValve would take you up to 115db or even a bit higher, and that is pretty darned loud.

For comparison, sitting in what I think are the best seats at the Disney concert hall here in L.A. (not too close, not too far), I heard a performance of Mahler's 6th and in the final movement when the big hammer blows come down, the peaks were right around 100db (as per radioshack spl meter). If I'd sat closer then it would have been louder but frankly I like it better not quite so loud!

martyo

Re: UltraValve Build
« Reply #32 on: 25 Sep 2012, 07:06 pm »

For comparison, sitting in what I think are the best seats at the Disney concert hall here in L.A. (not too close, not too far), I heard a performance of Mahler's 6th and in the final movement when the big hammer blows come down, the peaks were right around 100db (as per radioshack spl meter). If I'd sat closer then it would have been louder but frankly I like it better not quite so loud!

In the concert hall, live classical music, 100db sitting in the sweet spot. Contrary to some, loudness does matter, in classical too.  8)

TONEPUB

Re: UltraValve Build
« Reply #33 on: 24 Mar 2013, 03:34 pm »
Just curious, who built the amplifier we received for review?  Very nice.   Have been enjoying the heck out of this amp!  Review to follow soon...

avahifi

Re: UltraValve Build
« Reply #34 on: 24 Mar 2013, 04:15 pm »
Larry Jenkins built your Ultravalve amplifier.  He builds most of our power amplifiers and his workmanship is awesome. Better yet, he has all his own test equipment so I have to do is run the units for a day before shipping them.  Testing and any occasional de-bugging are already done for me.

Frank Van Alstine

TONEPUB

Re: UltraValve Build
« Reply #35 on: 24 Mar 2013, 04:30 pm »
I agree Frank!  It is beautifully built.

trackball02

Re: UltraValve Build
« Reply #36 on: 24 Mar 2013, 05:27 pm »
TONEPUB, I have personally found that swapping out the stock rectifier with a NOS Mullard and the signal tubes with NOS GEs really improved the sound quality. I am still running the sock EH tubes. Glad that your are enjoying the amp. It's fantastic.

pehare

Re: UltraValve Build
« Reply #37 on: 24 May 2016, 12:06 pm »
Can the Ultravalve be built with beefier binding posts?  Those of us with snake oil cables have large spades (WBT 8mm in my case) which need something stout or will the stock posts accommodate?  Thanks!

avahifi

Re: UltraValve Build
« Reply #38 on: 24 May 2016, 12:50 pm »
The physical layout just won't accommodate "good sounding" speaker terminals, such as they are.
 
I recommend using Bluejeans Cables locking banana plugs on your speaker wires.

Note that an Ultravalve amp without magic cables is probably going to sound better than anything else with magic cables.

The magic is in the design of our audio circuits, not in stupid pieces of wires.

Frank

PMAT

Re: UltraValve Build
« Reply #39 on: 24 May 2016, 03:07 pm »
 :lol: Frank, you are the best. "Stupid wire" made my day.  :lol: