Dynaco ST70 Upgrade

I just got a one of the Dynaco ST70  upgrade driver boards from http://www.tubes4hifi.com/ the VTA70 and I was very happy with both the performance and customer services from the folks at Vacuum Tube Audio.

This driver board came with great quality components, as well as great instructions on how to assemble the kit. I had to order a replacement current regulator and they sent one out within one day of getting my payment. They also sent another layout diagram to make sure that I installed the transistor correctly. The service was top notch.

This board replaces the single bias control per channel with individual bias controls for each of the output tubes. (2 per channel) It also replaces the large can filter cap with 4 common electrolytic capacitors  that are more cost effective to replace and easier to source.

So how does it sound? well after about 10 hours of listening all I can say is WOW it is a huge improvement over the old driver board, it sounds way more open and the sound stage is more focused. The amp also sounds much faster to me. I compared it to a Scott LK150 in the past before the upgrade the LK150 (stock) sounded much clearer and more transparent. and since the upgrade this ST70 is on par or exceeds the sound of the Scott. Overall I am in love with the new sound of my ST70.

As tested:

  • Dynaco ST70 with cloth leads on output transformers
  • Winged C Svetlana EL34 Tubes
  • RCA Blackplate NOS 12au7 Driver tubes in VTA70 driver board
  • JJ gz34 Rectifier

the other mods are Gold Input Jacks, Updated binding posts (banana plug) and Dale 1% Resistors and 99.99 Silver wire


The Fisher “FM-1000” Dr. Tubeology restore’s (update 4-7-12)

Very Rare! “Fisher FM-1000” When released by Avery Fisher this tuner was considered the best of the best. Fisher designed and built it to be a “broadcast” reference tuner. This began the “war” of tuner’s with Saul Marantz taking on the challenge to better it. The famed Marantz 10 & 10b sprang out of this. To this day both the FM1000 and the Marantz 10b are by most accounts the best two Stereo FM tuners ever built!.. Stay “tuned” as I begin a photo documentation of a full restoration on this rare component. Updates will be posted at various times. You will not want to miss this!…. in the end I will actually do a side by side listening comparison with my Marantz restored 10b

Dr. “Tubeology”


See our page “Tech Stuff” for a gallery of photos I have just added on the restoration progress of this famed Fisher FM-1000 tuner.. it’s moving right along. http://classictubeaudio.com/blog/tech-stuff/

an Ad for our 50-w2 – Mcintosh

50-w2 original ad  and we have one of these for sale if you are interested and yes they do sound better

Dr “Tubeology” at it…If you have a need?

Pictured the innards of a Fisher 500C, they use a similar design too Fisher 400 for the MPX FM Stereo decoder. The problem here was the MPX stereo diode decoders were not functioning correctly, solution “built my own” improved decoder. Here you see it being tested and the O’scope pic of the input to the decoder. It sounds pretty darn good after tweaking the alignment and getting finally stuffed into the chassis


The “SpinZone” Pas3x ….Fun on a Saturday

Pictured is a Pas3x that I have been doing some tweaks on for a customer. I have built a new power supply, added a few “designer” audio caps..some magic “Tubeology” dust .. sounds darn good..I needed a distraction from the everyday service work.. so its a Lazy Saturday project and I’m spin’n vinyl .. remember that?.. Let me tell you its refreshing the sound is much more real then digital.

Tube Monster – By James DeRosso

James DeRosso makes really cool monster sculptures of all types, when he was visiting me one day a few months ago he saw my tube collection and he asked for a few old tubes, well here is the result  if you would like to see some of his other monsters or if you want to commission your very own custom tube monster you can check out his website or blog here .

James DeRosso tube monster

James DeRosso tube monster and a Miniwatt ECL 80

In case you are wondering – the amp is an 18watt el84 / 6bq5 Marshall Plexi clone with a ppmv and the guitar is a 1968 Gibson es335

here is a more normal monster without the tube 🙂

James DeRosso Monsters - Portland, OR

A Tubeless Monster by James DeRosso - awesome