Up for sale/auction is the highly reviewed "tubes4hifi" replacement driver PCB for the Dynaco ST70 tube amplifier. This is for one fully assembled board, ready to install, and includes all documentation,
including schematic, parts list, and PCB layout with installation instructions. Our driver circuit is a modern all triode driver design, for totally neutral uncolored sound.
This is the same circuit we use for our ST70 mod and for our VTA70 and VTA120 amplifiers. Uses three 12AU7 tubes or equivalent (not included). Also available as a complete kit or bare PCBs.
There is an individual bias pot for each output tube, and a CCS circuit keeps balance perfect automatically.
This board blows away all of the competition, and is a better quality PCB for less money.
Our customer are the best sales people for our product, here's just a tiny sample of remarks from customers . . . .
"I finished your mod and this is honest to god the first time
I ever enjoyed listening to an ST70..The ST70s to me have always
sounded kind of sloppy, but this mod tightened it up and the overall
tonal balance is much much much better. The biggest thing I noticed
was the lininerity of the sound and the focus of the instruments
possess an exponential difference now as opposed to the stock ST70.
The amp is tighter and much faster."
Bill (VTA70 mod)
"Better highs, deeper and wider soundstage and tauter bass, more
transparent and better detail by a factor of 10. I heard an ST-70
with a Curcio upgrade last night driving the same speaker I have
and using a higly regarded preamp, and in my ears,
there is no contest. Thanks very much. A very happy customer."
John R. M.D. (VTA70 mod)
"hi roy
I put together the board of yours and then I wired it to my Dynaco ST70.
Let me tell you this is the most stable, accurate, fast, solid sounding
mod I've ever heard on a Dynaco... WOW.
I couldn't believe the drive they have. Oh by the way a friend of mine
had the Curcio modded amps and he heard these tonite and he said this is
a much better sounding design than the Curico."
mike (ST70 mod)
BEAUTIFUL WELL LAID OUT BOARDS AND EASY TO FOLLOW INSTRUCTIONS.EXCELLENT.A+++
Superior packing, very honest seller, A+'s all the way, very smooth transaction
Quality workmanship,quick shipping.Recommended!Thanks!
Nice amplifer, works great. It sounds better than my MC240! no problems!
Awesome product as promised!!!!! Nice and quick delivery!!!!!!
This is a great mod board. Just try it!
Now for the sound. Let's just say I used the board on a few Dynaco's and I was happy with the results as compared to other mod boards and stock boards I tried.
This is the best mod to an EL-34 amp I ever heard.
The music is about as real as it gets with lifelike images that make you feel the musicians and singers are in the room for a personal performance just for the listener.
The bass is extremely accurate and tight
Try this board! You will be glad you did and it is easy to install.
RE: VTA70 PCB kit
It is a real winner - finished the amp in one day and everything worked perfectly and all was very quiet.
This thing is pure and really belts out a tight bass, with expanded mids and brilliant highs.
I really think it outshines my MAC 225, and certainly beats any ST70 I have ever heard.
Roy, just a follow up to my recent order of a VTA board
I installed it last Sunday, which took no more than an hour. Fired it up, biased it per directions and everything immediately checked out OK.
To be succinct, the sound is incredible - much more robust, with depth and detail far, far beyond what I previously was hearing from the amp
I have the VTA MOD Dynaco ST70, and a freind of mine has the VTA MK3 mod, as far as I am concerned it is the best Dynaco upgrade ever, and it doesnt take a rocket scientist to install. check it out at tubes4hifi
Just installed the board in my ST70 and I have to say it sounds superb!
Hi Roy,
A note to let you know that I received the PCB and the parts I ordered.
The PCB is absolutely outstanding as compared to the Curcio!
It's clear that your intent was to give your customers a high quality PCB at a very reasonable cost.
I have only run my ST-70 a few hours (w/ all tubes new), and let me tell you how happy I am from the sweet sound I'm hearing. Compared to stock, well no comparison.
Better highs, deeper and wider soundstage and tauter bass, more transparent and better detail by a factor of 10. I heard an ST-70 with a Curcio upgrade
last night driving the same speaker I have and using a higly regarded preamp, and in my ears,
there is no contest. Thanks very much.
A very happy customer.
John R. M.D.
Hi Roy,
Received your VTA ST70 mod, and I am thrilled. I must say, the quality and craftsmanship that have gone into this board are truly exceptional.
You may be interested to know that before I ordered this board from you I did my homework, and investigated most of the mod boards being offered by other companies. Time and again, yours was rated by far the best, and now I can see why. I didn't realize that part of your mod board INCLUDES additional power supply filter caps,
When I finished the project, and powered it up according to instructions, and everything seemed just fine,
but at first I thought there was something wrong because I couldn't hear any hum at all through the speakers.
Then the music started. WOW! This is an amazing board you've designed. It has tons of power, plus great range.
Amazing !! Thanks for going the extra mile for me
-Peter S
This amp is absolutely LIQUIED. The sound stage is large and has wonderful detail!
I would recomend this MOD for any ST70 Steve (VTA70 mod)
Your board sounds really nice! I will recommend it to my friends with Dynaco Stereo 70's.
To be honest the Dynaco just didn't cut the mustard in stock form but now it’s a whole new animal.
Joe
Just a note to let you know how much I enjoy the driver board I purchased from you.
It made a night and day difference in the way the Dynaco sounded. I had heard people rave about the stock Dynaco ST70 so I bought one only to be disappointed by its sonic signature. I was assuming that it would have some bass and authority but it actually sounded very bad instead.
Your circuit changes and your board brought it new life and authority that it should have had if it had been designed correctly in the first place.
It ranks up with my "quicksilver" amps now and frankly if I had had the modified Dynaco first I never would have bought them. They sit gathering dust now while I use the Dynaco with you VTA70 modification.
Best Regards,
Joe T
Your ST-70 mod board is by far the best sounding one I've ever heard. I'm truly impressed by the improvement in sound and the other benefits of the board, like seperate biasing for the EL34's. I didn't expect anything good when I bought it, but had to try it as I've tried everything for the ST-70. I'll spread the word. And Thanks!