Will Vincent "Dynaco" Amps

I would like to field opinions on Will Vincents Dynaco amps. I am interested in his complete rebuilds of these classics and would love to read opinions from owner.
I like what I see on the appearance side of the amps made by him. I think his work is excellent. But.... I wish he would include a new circuit on the input boards. I think those 7199's are good tubes but there are better tubes used in several other mods. I would seriously listen to mods using 6GH8's, 6DJ8's, 6SN7's, 12AX7's, 6LU8's(a 6GH8 variant) before deciding on the 7199 circuit. I am using a Sound Values Board with Telefunken 6LU8's and it's wonderful. My board was mofified by Tom Tutay as was the rest of my amp. Most of the same mods I have are in the Vincent amps with the exception of the input boards. Some people think the 7199's are excellent tubes since they were designed for audio. After owning well over 50 ST70's of various mods I like mine best. I have owned many much more expensive amps both solid state and tube and my Dyna is still going over 10 years after I bought it and along with my Spica TC60's will make you smile.

Some mods I would choose over his are VanAlstine, GSI, Audio Research C70 (?) and of course Transition Audio Design. Mine is the latter. There are many many different mods for the ST70 and opinions will vary on this topic but I prefer that the 7199's be gone! I hope this does not cause a controversy. It's just my opinion.
bill thomas' work is great too, over at audiocircle. look under the vintage audio forum.
I have one of Will's Dynaco ST-70 rebuilds. I have found it to be a very good amp. It has a nice smooth sound. It also very good bass for a lower powered tube amp. Though the sound was good the way it came, i couldn't help but roll some tubes. I ended up with winged "C" el-34's, RCA 7199's and a Mullard gz-34. With these tubes i feel the amp jumps up another level or two. The tube that made the biggest difference was the gz-34. They aren't cheap, but the improvement it made to the overall sound is well worth it.
I have one of Will's st 70 amps and it is a piece of art.

The amp sounded nice with the el34 tubes in it, but I also wanted to try some tube rolling..... and after a matched quad of gold lion kt66 re issues, this amp has unreal depth, imaging, and much better detail than before.

Now I need a real pair of speakers... I currently have quad 11L mini monitors.

It does not hurt that I am using a classe audio dr6 preamp, but even after adding the pre the magic was not there until I added the kt 66 tubes.

As an added benefit from the kt 66's , they run MUCH cooler than the el 34's and were easy to bias since Will puts in an extended range very high quality bias pots in his amps.
I've got a pair of Will's Dynaco mk iiis; beautiful aesthetics and sonics. Just one word on the looks: WAF was off the scale (glowing tubes!), and everyone who comes in the living room makes a beeline for them.
I was not aware i could use kt66 tubes in this amp. I know i can use kt77's. I will have to look into this. By the way the amp is a work of art. My girlfriend thought it was a bomb when i openend the box, but i think it looked great.

I found some threads dedicated to st70 upgrades and one of the mods was using the kt66 gold lion re issue tubes.

Before I ordered a matched quad, I called Will to make sure they would work properly with the amp and he said yes.

In Will's reworked st70's you can use el34, kt77, kt66, and I think he said 6L6 also. He uses upgraded bias pots that have a wider range than the original's and all you have to do is adjust the bias to 1.5 - 1.55 volts on your new tubes. (The kt66 tubes required the bias to be adjusted down compared to the el34 since they use less current than an el34)

The soundstage width, depth, "holographic" imaging and high end detail all improved so much with the kt66 tubes, I could not believe it was the same amp!

The gold lion re issue's don't come cheap, but I am very happy I put a set in.

Good luck and enjoy your new amp.
I almost forgot.... the kt66 tubes are the "coke bottle" shape and they make this already cool looking modded st70 really "off the hook"!!!
I use the Gold Lion KT-66's.....and I agree with the posts on how great they sound. I paid 150 bucks for a quad though, a bit on the expensive side if you ask me.

The KT66's did add a more spacious sound to the amp, and there was more detail in the high end and the mids. I run a pair of Klipsh Heresey's myself.

All you need to do is replace the two 10k in the bias section with a couple of 4.7k. Then put in a couple of 25k bias pots to replace the two 10k pots.

Once I tried a set of KT66's though I was hooked. I didn't even have to get any burn time on the KT's to hear the difference, it was that apparent to me from the moment I installed them.
I go through a lot of amps, but the one amp that I will never sell is my Will Vincent Dynaco ST-70. Sometimes the ST-70 will be put on a shelf for a month or two while I try something else. (I'm currently having what I think will be a brief fling with a SET amp.) But every time I bring Will's ST-70 back into rotation I am floored by its presence, soundstage, and very good. very natural bass. Upgrade the rectifier tube, leave the El-34 tubes alone. Best amp I own
Just received my Will Vincent Dyna Super 70 amp with 6L6's with triode output of 21 watts per channel. Wow!!! Right out of the box this thing is transparent and detailed with warmth in the midrange with nice tight bass. The retrieval of low level information is astonishing with my 96db Omega MaxHemp V2's (and I didn't even get my Lightspeed preamp yet! When it sees 470K ohm input impedance of Will's amp, I'm sure things will really get cooking! Thank you Will.
I realize I sound like a broken record here on Audiogon, but excepting absolute power and low frequency performance, the Dynaco ST70, fitted with modern parts, eclipses most high-end audio amplifiers of today.

I believe Will Vincent's offerings are an excellent choice for anyone interested in purchasing an ST70.
My fantasy shootout would include many of the Dynaco rebuilds mentioned above, along with Jim Nicholl's version, (speaking of broken records, haha).
Will Vincent vs Bob Latino??
The kit offered by Kevin Carter at K&K Audio has always been of interest to me. Turns the original 35 watts per side into 10 watts triode.
Linkster, "Will Vincent vs Bob Latino??"

Simply a question of whether you prefer the original Dynaco Concertina circuit (Will Vincent), or one of the upgrades that "fixed" what was wrong with the original (VTA/Bob Latino) ala the Mullard long tail pair driver.

Historically the answer has been the Mullard LTP, with the experts pointing out all of the inherent flaws in the Concertina that had to be addressed.

As for me, I seem to be one of the few who trumpets the Concertina, appreciates beauty and simplicity in general, and this circuit in particular. Not to take ANYTHING away from the VTA, but I think the original has been long overlooked, underrated/underappreciated, and truly quite special. In fact, a guy I converse with began writing to me two days ago, commented on how happy his Jadis Orchestra Reference makes him, and related that he simply does not hear the same magical midrange in a friend's DA50S. He was likely quite surprised for me telling him the JOR simply employs what Dynaco made famous.
A testament to the quality of Dynaco's original circuits is that their products were made using low tolerance, inexpensive parts (with the exception of the transformers, of course) and they were often built by complete amateurs (most people don't know that "Factory Assembled" units were built by starving Drexel University students) yet they still sounded quite respectable.

But these designs had their weak points, too. Since they were intended to be built as kits, they often made compromises in the grounding and power distribution in order to make assembly easier. From personal experience, I can tell you that one can greatly improve the sound of a stock Stereo 70 by simply changing the way the cathodes of the output tubes are grounded and by changing the reference ground points for the feedback circuit.
does anyone have contact info for Will Vincent?
Will Vincent is Autospec.
Anybody know how to get hold of Will. I have one of his amps and it crapped out on me. Great amplifier when it was working. Beat the crap out my MC-352 amp from Mac