AudioCircle
Industry Circles => Audio by Van Alstine => Topic started by: avahifi_lj on 7 Jan 2012, 06:16 pm
-
Hi,
I'm building an UltraValve amplifier. I thought you might want to see progress photos. This first one is some of the parts that go inside of he chassis. I included an assembled audio board otherwise all you would have seen is a bunch of parts and an empty board. The raw chassis is also not shown as it's covered in white plastic until the final assembly, and white-on-white is hard to see...
Larry
(http://www.audiocircle.com/image.php?id=56043)
-
Cool idea, thanks. 8)
-
Larry,
Be careful. You may end up sparking a demand for a kit version!!! :thumb:
Ron
-
Fantastic initiative, Larry, thank you! :banana piano:
-
Hi,
Here is a photo of the chassis parts mounted before the transformers are installed. The two holes at the bottom are where the tubes go through the chassis. The next photo will show the transformer wiring.
Larry
(http://www.audiocircle.com/image.php?id=56114)
-
Hello from tropical Minnesota,
Today, January 10, 2012, we had a temperature of 54 degrees. Some of the golf courses were open, and I saw a lot of people walking around the lake (yes, it's frozen over). With temps like this I could grow to like winter in Minnesota. As you might expect, however, we are in for a big change starting tonight with some four letter "S" word (I don't like to cuss too much), then the temps drop down to the mid-teens by the weekend. At least I did get out over the lunch hour today....
This photo is the third major phase of building. All of the major point-to-point wiring is done, and most of the hardware is installed. As you can see it's easier to route the wiring before the audio board is installed.
I should also mention that we recently changed the UltraValve chassis to incorporate the IEC power jack that we are putting in all of our other new products. To accommodate the IEC jack and the ground lift switch we did a slight bit of rearranging of the back panel. Wayner did an excellent job of fitting all the new items.
The next step is to finish up the audio board, install the parts needed to interface the tubes to the audio board, then install the board. Pretty soon I'll be ready for the magic smoke test :D
Thanks,
Larry
(http://www.audiocircle.com/image.php?id=56184)
-
Hi,
This is a photo of the completed amplifier. Since the last photo the board was installed, the part and connections from the tube sockets added, the AC power switch and AV wiring added, and the signal wires were connected to the audio board.
All that is left is to test out the amp, remove the protective film, remove my finger prints, and install the base. The next update will be the test results....
Larry
(http://www.audiocircle.com/image.php?id=56285)
-
Works like a champ!
Before testing the amp I double check all the point-to-point wiring, put in all the tubes, and set the bias pots to minimum. Next, I hook up the scope, signal generator, output loads, and plug the amp into a Variac.
With the Variac set to low/off I begin the test by bringing the Variac up about 30% and check that the bias voltage is working. At this point the tubes are starting to heat up, but have yet to start conducting/working. I bring the Variac to 60-70% and continue monitoring the B+ voltage, the raw bias voltage, and the bias voltage at the output tubes. As the tubes begin working the output begins to show up on the scope. Once I see that the amp is working, I continue to slowly bring up the Variac to 120V while monitoring the B+ voltage.
I let the amp sit for a serveral minutes to allow the tubes to settle into the operating state. I also monitor the bias voltage at the tubes, but don't set the bias as the voltage will drift around as the amp heats up. During the initial warm up I start looking at the general operation of the amp by seeing how the signal looks on the scope. Once I'm convinced that the amp is running properly, I set the bias voltage on the output tubes, then do a suite of tests to see how the amp behaves. The tests include looking at the amplifier bandwidth, the output voltage (Watts out), the clipping nature of the amp, the noise floor, and the overall quality of the signal produced.
I'm almost done with this amp, but there is still stuff to do before it's ready to ship. Once I'm done I will hand the UltraValve off to Frank who will give it one final polish, print the owner's manual and warranty information, then put the amp into its cocoon box for shipment. Remember to keep the box as it's the best way to ship your UltlraValve amplifier.
The photo below is a 1KHz sign wave out of this amp.
Larry
(http://www.audiocircle.com/image.php?id=56346)
-
Finished pics? I'd love to build a tube amp. :thumb: I'm in MN too. Finally getting a little snow today. :D
-
Look at Larry's work :thumb:. He made my amp! I am happy :thumb:.
:smoke:
-
Beautiful work Larry.
-
Nice work, I loved seeing the different steps to making these great amps. Thank you for posting it.
have a great day
Crazy Nocturne
-
Larry buids many of our power amplifiers, big and small. His workmanship is impecable. He has all of his own test equipment so that with his finished units, all I need to do is burn them in for a day and pack and ship them. He really makes life easy for us.
We are now building a new Fet Valve 600R for The Absolute Sound. Larry insisted that he build this one because his finished wiring layout is even nicer than mine. Well, OK Larry! I don't mind being second best to him.
Best regards,
Frank
-
I guess this is the place for me to post that I love my U70!!!
:)
I have performed all the mods, choke and diodes. Also put in upgraded speaker binding posts and input jacks. I am toying with the idea of replacing the tube sockets with upgraded sockets and maybe even rewiring the thing with either better wire or silver core wire. That seems like it might be a big job though, I also think that the silver wire is just silly, and stupid...
-
Hi,
Here is the finished amp. There has been questions on how to remove finger prints. I use a microfiber towel with a bit of moisture, and gently buff out any fingerprints. I have one of these amps in my system, and I have noticed a dust haze forms. I use a Swiffer duster to remove the dust, and if I want to get the mirror shine I use the microfiber towel.
The amp is off to Frank, and should be shipped soon. I hope you liked seeing part of the build process.
Larry
(http://www.audiocircle.com/image.php?id=56728)
-
Hi,
Great build and thanks for posting. I'd like to buy one of these amps one day.
Regards
Rod
-
Great work Larry and thanks for the cleaning tips. The UltraValve in my opinion is the best looking modern production amp in audio. No comments to the sound because I have yet to hear one. My only critique is the large space between the PA060 and the chassis. Wouldn’t isolation between the PT and chassis be possible with some thin neoprene washers? Just wondering.
Thanks,
Brad
-
Great work Larry and thanks for the cleaning tips. The UltraValve in my opinion is the best looking modern production amp in audio. No comments to the sound because I have yet to hear one. My only critique is the large space between the PA060 and the chassis. Wouldn’t isolation between the PT and chassis be possible with some thin neoprene washers? Just wondering.
Thanks,
Brad
Hi,
There are washers between the power transformer and the chassis. The washers add a bit to the space between the transformer and the chassis, but we inlcude the wahers to help reduce the transformer hum coupled to the chassis.
Thanks,
Larry
-
What gauge of hookup wire do you use for the Ultravalve, Larry? Also if you don't mine giving me the part number for those blue color cap, so I know they are the sure fit for the board. I need to get going on mine.
Thanks
-
Hi,
We use 20 and 18 guage wire. The blue caps are 2.2 uF 400 volt film.
Larry
-
They are EPCOS P/N B32924F3225K. Get 'em at Allied Electronics, Digi-Key, Mouser, etc.
http://www.alliedelec.com/search/productdetail.aspx?SKU=70102592
http://parts.digikey.com/1/parts/1875820-cap-film-2-2uf-400vdc-radial-b32654a4225k.html
Ron
-
Thanks Ron.
-
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?
-
Kevin has the kits.
-
Do you mean the kit for the individual bias adjust? Does Kevin's bias kit drop right into the UV?
-
Do I see an IEC power connector ? Finally, support for magical power cords ;-) ;-) ;-)
CE
-
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
-
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
-
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
-
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.
-
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
-
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!
-
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)
-
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...
-
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
-
I agree Frank! It is beautifully built.
-
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.
-
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!
-
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
-
:lol: Frank, you are the best. "Stupid wire" made my day. :lol:
-
Good handmanship. Looking great
-
Just went down an ST-70 rabbit hole. Glad I found this forum/thread :)
-
I need let you all know that our two transformer vendors are out of stock (and have been for many weeks now) and neither have any idea when they may have more available.
Thus our Ultravalve amplifier is now listed as unobtanium, in the same catagory as AKM digital chips.
If we ever have access to a reliable source for more power and output transformers, we will build some more Ultravalves. But for now its impossible.
Frank
-
The transformers are on a ship somewhere by the coast.
-
The transformers are on a ship somewhere by the coast.
Sittin' on the Dock of the Bay? With all the Otis Redding's Greatest Hits albums?