Free major Ultimate 70 amplifier upgrade.

Wayner · « **Reply #120 on:** 23 Jun 2009, 11:56 am »

Well I have to ask what preamp you guys that did the mod are using? I'm running the Insight EC with phono and buffer option. How bout you?

Wayner

simon wagstaff · « **Reply #121 on:** 23 Jun 2009, 12:34 pm »

Since you asked...

I am using a Pioneer tsx 59i surround receiver as a pre-amp for my front channels with a pioneer 79avi connected via firewire....

running a pair of Infinity Intermezzo 4.1
with a pair of VMPS smaller subs.

Wally King · « **Reply #122 on:** 23 Jun 2009, 01:00 pm »

Frank,

Since you're running a pair of the Ultravalve amps to drive your Salk HT-3s, would it be safe to assume that one Ultravalve will not be sufficient to drive the HT-3s?

Or, would one amp be OK for something like a piano trio, while for big, complex orchestral pieces the amp might peter out.

Right now, I'm using a 550 to drive my HT-3s.

avahifi · « **Reply #123 on:** 23 Jun 2009, 01:03 pm »

One U70 sounds great with my HT3s, up to reasonable listening levels. But, as you suggest, if you are playing Telarc CDs or similar, you need more power. A pair of U70s bridged with an Insight Bridge does just fine, actually more than just fine.

Regards,

Frank

avahifi · « **Reply #124 on:** 23 Jun 2009, 08:16 pm »

Hi Hotroady,

I swapped to the output tube set you dropped off yesterday and rebiased the Ultravalve amp for them. Your set appears to be identical JJ EL34s as to what I was using in that amp but probably newer ones. The bias setting has to be turned down a little with your tubes.

On the bench and in my system the performance was identical as far as anyone can hear hear. The newer JJ tubes made no useful difference. The overall performance remains a lot more than useful. The Salk HT3s can be run just about as loud as I care to drive them in my listening room with one Ultravalve 80 amplifier. I still am not sure why. I do note that on the test bench the amp clips amazingly cleanly, just quits getting louder with no nasty side effects at all. Square wave performance is outstanding, pure exponential rising and falling signals and no slewing at any frequency up to the 3 meg limits of my generator with zero overshoot or ripple. That is what happens when you get the ratio of nested time constants really dead on right.

I still have to swap in the set of matched EH 6CA7 tubes from my other Ultravalve prototype into this amp. I did think the EH 6CA7 tubes made a positive performance difference. Now I need to find out if it was just the output tubes or some other variation in the amplifiers that I have not identified yet. That is on tomorrow's to-do list. It sure is nice to have two hopefully identical amps when playing with tube rolling.

Thanks for the loan. Call me and retrieve your JJ EL34s whenever you want. 651-330-9871

Regards,

Frank

avahifi · « **Reply #125 on:** 23 Jun 2009, 08:22 pm »

Nice idea Kevin, using the terminal strip to eliminate the need for two wires in one hole.

Note that I normally measure the B+ voltages on the top side. There is enough of the wires coming thru the PC card holes at the old quad filter cap cutout to make contact on the component side of the board.

I hope you got the power switch and the info from Wayne to make the changes needed to come up with the additional faceplate. If using blind tapped holes to mount the faceplate will be "iffy" then through holes for our normal #6 mounting hardware will be just fine, assuming I can get the button head allen screws long enough to get thru the faceplate and chassis.

I am glad you like the improved sonic quality.

Best regards,

Frank Van Alstine

hotroady · « **Reply #126 on:** 23 Jun 2009, 09:30 pm »

"Now I need to find out if it was just the output tubes or some other variation in the amplifiers that I have not identified yet. That is on tomorrow's to-do list." I dunno, something strange maybe going on in this area, IMHO. I had put 2 EH34's, on one side and 2 JJ34L's, on the other channel. I left the bias alone, as it only varied from line voltage. The EH34 held the same exact bias as the JJ's. I had tested with my lesser Superior tube tester; time to break out 'IGOR' and see if he can find in difference in tubes. I had a completely different experience with the EH tubes. Both times I tried, I did not make it back to my chair, before I noticed a dive in performance, out of the EH channel

. My experience was that the EH was a competant tube, up to the point of the update; then fell down. Makes me think the updated U70 responds differently to tube swaps, than latest UltraValve prototype circuit. The RCA GH8's actually brought about a new level of transperancy and rounded any residual edge on CD's. Deeper into that 'deep pool' thing that was discussed. Really like the tone match with the GE's. I Really thought it would do the same thing for your set up. I am perplexed, as to the differing results. Certainly warrants further investigation. Why such a sharp contrast in results?? I assume neither one of us is full of the brown excreet. But there is a simple way to resolve this. So far the update; the update along with changes I made have exceeded all expectations. aa

hotroady · « **Reply #127 on:** 23 Jun 2009, 10:22 pm »

Ok! Talked to Frank on the phone. I misunderstood what occurred. When I last saw his set up; he had 2 bridged mono prototypes. He is running the one amp, now. He, in essence; was only comparing the JJ 34's to the JJ34L's. Tomorrow, he will switch to a matched set of EH 6AC7/EL34's! Results still pending on this 'taste' test. Makes a lot more sense, already!

boycephoto · « **Reply #128 on:** 24 Jun 2009, 10:58 pm »

Hey Wayner,

I use a AVA Super Pas 3 (with NOS Telefunken 12ax7) with my Ultimate 70. I am sending my OmegaStar EC to Frank tomorrow for the Insight+ upgrade. It has a phono and phase inverter. I also have a Super 70i that I will soon upgrade to a U70 so I will have a pair to use with my updated Insight EC.

Maybe you should try a pair of U70's on you Logans??

Dave

BrianM · « **Reply #129 on:** 25 Jun 2009, 12:29 pm »

Quote from: avahifi on 22 Jun 2009, 06:33 pm

It looks like the price of the new Ultravalve amp will be in the $1995 to $2295 range.

Okay, that's more than I thought. And will the factory rebuild of a Dynaco ST-70 to UltraValve still be $899?

avahifi · « **Reply #130 on:** 25 Jun 2009, 02:53 pm »

The factory rebuild of the original Dyna 70 will have to go up a bunch too. My bookkeeper tells me me I am giving them away because I have vastly been underestimating the labor time (based upon how quickly I could rework a clean properly wired used St-70 myself). Now most we see are nearly junk and take much more time to just put back into good operating condition. Lots of aged and intermittant solder connections to the tube sockets, lots of dirt and dead bugs to remove, etc. And of course my parts and labor costs keep going up up up too.

We will try and hold the price on the U70 rebuild kit for a while, but the factory rebuild will go up in price substantially soon.

By the way, after another quick "tube rolling" session, I can report that so far I am happiest with Electro Harmonix 6CA7 (big envelope) tubes in the updated U70 amp. I need to try the JJ KT77 tubes again but do not have any on hand right now.

Regards,

Frank Van Alstine

oneinthepipe · « **Reply #131 on:** 26 Jun 2009, 01:27 am »

Frank:

I have a Super 70i. It was not factory-built but operates without any problem. The only modification is a three prong power cord that is wired correctly, although I do not have any hesitation installing a two-prong cord. If I complete the upgrade myself, is upgrading a Super 70i to a U70 any easier or less complicated than upgrading a stock ST-70 to a U70?

iclark · « **Reply #132 on:** 26 Jun 2009, 02:32 am »

Oneinthepipe,
My U70 started life as a 70i as purchased off ebay. Upgrading to a U70 from a 70i was easy as most of the work was done previously in the 70i mod. I don't know the history of my 70i, wether is was done by AVA or from a kit, but I thought it was very good until I did the upgrade to a U70. All that is required is to swap out the main circuit board and wiring it in. Frank can give you more information, in fact I think it is available on his site. As usual his instructions are very clear and concise. I chose to just buy the circuit board, but if I had to do it again I would buy the comple kit. I had trouble sourcing some of the parts. (untill I discovered Digikey, they are amazing for parts)

Ian

simon wagstaff · « **Reply #133 on:** 26 Jun 2009, 10:57 am »

Listened to the SACD of Satanic Majesties Request last night. Wow1 This new upgrade is as good or better than a new pair of speakers. Again, heard things I have never heard before.

My question is: does the amp basically measure the same before and after? I mean the usual things like frequency response, S/N ratio etc? I am wondering if this is one of those things that can't be measured but can be heard clearly?

boycephoto · « **Reply #134 on:** 27 Jun 2009, 01:56 am »

The hardest part of upgrading from a Super 70i to the U70 is putting the components in the right place and soldering them onto the circuit board, it also takes the most time and is the most delicate and tedious.

Good luck
Dave

boycephoto · « **Reply #135 on:** 27 Jun 2009, 02:12 am »

Hi Ian,

I am sure you realize there is a significant difference in sound between the S70i and the U70. If your up for the upgrade it is well worth the effort.

I have a Super Pas 3 that I use my U70 (AND LIKE IT VERY MUCH) with but , I just sent my OmegaStar EC to Frank yesterday for the Insight+ upgrade. I will know in a few weeks just how much better the Insight+than the Super Pas 3. Check in for my take and the two pre amps in a little while.

Dave

iclark · « **Reply #136 on:** 27 Jun 2009, 03:10 am »

Hi Boyce.
That would be great to hear your first hand comparison between a Super Pas 3 and the Insight.
I am starting to think that I should order a Insight and be done with it. I also would like to play with an old PAS preamp, if I can find one for a reasonable price. Upgrading it with the AVA Super kit would make nice project for next winter. (too much going on in the Summer).

Ian

boycephoto · « **Reply #137 on:** 27 Jun 2009, 03:19 pm »

Good Morning Ian,

It will be a few weeks before I get my Insight+ back for AVA, will post my thoughts and ideas after I have a chance to listen to both preamps side by side.

Ottawa is a beautiful city, I love to visit it.

Dave
in Kalamazoo

iclark · « **Reply #138 on:** 27 Jun 2009, 08:19 pm »

Hi Dave,
From your picture, Kalamazoo looks very pretty. I have been to Northern Michigan a few times to look for the famous and rare Kirkland's Warbler (another hobby, bird photography), but I have never been in your neck of the woods.
Today I was bad and purchased a PAS 3 off Canuck Audio Mart. Unfortunatly it has been modded already by McAlister Audio, which may or not be a good thing. This will tide me over until I get my Insight in the fall.
The phono looks stock so I may just order Franks Super PAS kit. I am not sure what he has done to the powersupply, but I can see that the tube recifier is gone.
If Frank is paying attention, what do you think. Can it be brought up to a Super Pas with your kit.

http://www.audiocircle.com/index.php?action=gallery;area=browse;album=1941

I am sorry for taking up peoples time on a thread devoted
to the Ultimate 70 mod, these topics sometimes get off track.

Still enjoying my U70, infact so much so that I am thinking of doing a complete rebuild with a new chassis and faceplate. The old chassis looks pretty beat up. The Front Panel Express software looks very cool. Do I need your permission to put your name on the panel Frank?

Ian

avahifi · « **Reply #139 on:** 28 Jun 2009, 03:00 pm »

You certainly may put an AVA name on a Panel Express faceplate for your U70 amp, as long as it does not come out too tacky looking.

Regarding the PAS preamp you bought, I hope you did not pay too much for it. It appears that there are enough original parts left so a Super Pas Three rebuild kit will work. You will need a new 12X4 rectifier tube and socket. I am also suspect of the power transformer as this "mod" photo shows two separate transformers. Why? Note that better than new transformer replacements were available from Triode for under $40 the last time I looked.

Regards,

Frank Van Alstine