Free major Ultimate 70 amplifier upgrade.

WGH · « **Reply #20 on:** 10 Jun 2009, 02:21 pm »

Quote from: Wayner on 10 Jun 2009, 02:02 pm

I really screwed up on this one. I forgot I have the proto-type U70 with goofy wiring (it's a proto-type) and the existing boards of the current U70's do not look like mine. Sorry for the screw-up. Your boards will not look like mine. Mine is unique.

Wayner

The wiring did did look a little...ummm...creative.

If anyone has photos of the mod on a production unit let me know and I can post your photos.

WGH

Wayner · « **Reply #21 on:** 10 Jun 2009, 03:55 pm »

Thanks Wayne!

Wayner

avahifi · « **Reply #22 on:** 10 Jun 2009, 04:23 pm »

In the photo below from the U70 page at our web site, the part of the board we are talking about shows up, partially obscured, in the top right hand corner of the board. The wiring is accessed from the bottom of the board through the old quad filter cap hole.

Frank

http://www.avahifi.com/root/equipment/amplifier/ultimate70.htm

iclark · « **Reply #23 on:** 11 Jun 2009, 03:29 am »

Thanks Frank. I did the mod in about 10 min. Dead easy!
Rebiased the tubes and turned it on. It truly is a significant upgrade. I never dreamed that what I thought sounded wonderful, could sound even better. I was very happy with my U70 and I am even happier now.
Thanks again.
I know you are planning a new version of the U70, have you ever thought about designing a tube amp from the ground up without the Dynaco 70 legacy.

Ian

Wayner · « **Reply #24 on:** 11 Jun 2009, 11:48 am »

I think the new U70 is so far away from the original design, your wish has already come true!

Wayner

Wayner · « **Reply #25 on:** 11 Jun 2009, 07:58 pm »

Ian,

Have you been listening lately to the upgrade? Where the hell is the bass (big and deep) coming from? I asked Frank and all he said was it was "magic". Perhaps it must be, but I'm hearing a 33 watt per channel tube amp that now must think it's a 100 watt per channel amp. I was listening to some FM (KSJN HD) at low level and this incredable bass came out of no-where and really caught me off guard. The amp is also very, very fast with extended high end as well. I don't even think it's the same amp.

Wow.

Wayner

boycephoto · « **Reply #26 on:** 11 Jun 2009, 08:48 pm »

Wayner, your comments are driving me nuts, I can't wait to make the changes in my U70. But...I am leaving for vacation tomorrow and won't be back until the 23rd. Maybe I will just postpone vacation so I can listen to my updated U70 for the next week and a half.

Art_Chicago · « **Reply #27 on:** 11 Jun 2009, 08:50 pm »

Wayner, I sent you PM
Thank you

Wayner · « **Reply #28 on:** 11 Jun 2009, 08:53 pm »

boycephoto,

I'm sorry. It takes me awhile to catch on to how a piece changes after a modification. Me thinks that Frank is so learned on his own products "signature", that he knows in a minute if it is an improvement or not. I'm a slower boat then that. However, I do catch up and am becoming more and more impressed with the results. I guess I have to listen to a few of my favorite recordings before I make judgement, but the verdict is in.

Wayner

iclark · « **Reply #29 on:** 12 Jun 2009, 05:11 pm »

Wayner,
I did notice the base, now that you mention it. I have a pair of 12 in. Tannoy's and was always a little disappointed in their base, not any more. (is it bass or Base?)

Ian

tgp06 · « **Reply #30 on:** 12 Jun 2009, 05:57 pm »

bass is correct-hate to act like a grammar or spelling cop!

TomW16 · « **Reply #31 on:** 12 Jun 2009, 07:47 pm »

I though bass was a type of fish

mark funk · « **Reply #32 on:** 12 Jun 2009, 09:03 pm »

Some guys I know go for some kind of fish called a Bottle Bass

Wayner · « **Reply #33 on:** 12 Jun 2009, 09:44 pm »

Yummmm, bottle bass. Having one right now (Budwiser Select in bottle). I've been looking for bottle treble, can't seem to find it anywhere!

Now PLaying: Genesis - Robbery Assult and Battery (MoFi).

simon wagstaff · « **Reply #34 on:** 13 Jun 2009, 01:25 pm »

Did I miss something? would love to see the photos as I am going to do this as soon as I get a chance.

avahifi · « **Reply #35 on:** 13 Jun 2009, 06:37 pm »

Look at the top right corner of the PC card in this photo.

http://www.avahifi.com/root/equipment/amplifier/ultimate70.htm

Maybe somebody here can post a better picture of the U70 board.

Frank

simon wagstaff · « **Reply #36 on:** 13 Jun 2009, 10:07 pm »

Hah! Nope, got it. It is easy to figure out once you take a look at the circuit board from the top down. Everything is clearly marked to the upper right corner of the board. Best to get to it by removing the bottom cover and going in from that direction.

is it possible that such a simple change makes such a difference? Did it this afternoon and fired up Pink Floyd "Wish you were here", the remaster, music I have heard many times. Detail I think is improved but the dynamics are way kicked up from before. Not the big crescendos, but the little bits inside the music pop out a lot more, you notice little guitar parts in the background and cymbal "splasssshhhhhssss" in the background with lots of reverb decay and poppy attack. Also the layers of vocals were more clearly revealed.

I heard stuff I hadn't heard before...

I was pleased before, I am even more pleased now. The synergy between the U70 and my Infinity IM 4.1 and this amp is very strong. The IM 4.1 has an 850 watts sub amp so I can't comment on the bass improvement that others have remarked upon. The U70 is a terrific match for any of the speakers with powered bass sections, like the mythos, I would think, but I certainly know with the IM4.1 things work very well.

So, is it possible that this little switching around of a couple of wires makes such a big difference? Or is it just me?

simon wagstaff · « **Reply #37 on:** 14 Jun 2009, 12:50 pm »

While we are on the subject of U70's I have a couple of questions.

I have two sets of tubes, one set of Mullards and one set of something else, I don't remember. One of the Mullards has gone bad and during the re-biasing I notices that one of the other set seems to be bad as I can't get the bias above about 1.46. when I move the tubes around this bias problem moves with the tubes so I can figure out which one easily. IN the near term I am just running them at 1.46 but if I were to use two tubes from each set should I mix them per channel so each side gets the same tubes or should I put them same make per channel? they are the same tube type.

I have read an earlier thread about different tubes for the u70. what is recommended?

And finally, my IM 4.1 has a built in crossover at 80 hz for the sub. I am using a Pioneer TSX 59i hooked up to an AV79i via firewire. I run the U70 from the analogue out of the receiver. Currently I am running it full range, it does get the bass signal but no minimal load. Would there be an advantage to running the front speakers as small, setting the crossover for 80 hz so that the U70 doesn't even see the signal below 80hz?

Looking forward to listening to my "new" U70 some more today. thanks for all the help!

Wayner · « **Reply #38 on:** 14 Jun 2009, 05:02 pm »

Frank is running 2 U70's in bridge mode (with AVA bridge module) and then driving each of his Salk HT3's with each amp. He told me he's getting great results with the amp into his 85ish db efficient Salk speakers. I'm driving my 91 db efficient Dynaco A25XLs with the amp in it's ordinary stereo mode boast a wopping 33 watts RMS per channel and they Dynacos are happy as pigs in mud. Plenty of power to drive these bad boys to reasonable levels with amazing dynamic range, detail and holographic projection. I would personally not need a sub-woofer, but can understand how this may vary from system to system and of course, room size and for love of the bass.

Wayner

sueata1 · « **Reply #39 on:** 15 Jun 2009, 02:05 am »

Hey Guy's,,,
Well I had to jump in on this one and now my U70 rectifier tube looks like a X-mas tree and the main fuse (3amp slo-blo) blo's

Help,,,,,
Mel