Hey JoeE SP9

[tin ear]

You wrote in another thread:

I suppose my Dynaco MK3's would qualify as vintage if they weren't so modified. Only the transformers and output tubes are the same. I'm still using 6550's although they are not the original tubes.

I didn't want to threadjack, but I am curious about your MkIII mods. What are they? Did you DIY, build kits, have them done?

Thanks for any info you can provide. I just got a ST 70, and I can tell I will be playing with Dyna stuff for quite a while.

-Jon

[JoeE SP9]

The whole thing started thirty years ago when I replaced the GZ34 rectifier tube with diodes. This worked for a while but the fast start nature of the diodes shortened the life of the output tubes. After blowing 5 GE6550's I realized I needed a slow start power supply circuit. After solving that problem I figured I could do even better with a different input driver tube. One thing led to another and I ended up designing my own input driver boards. Different input and speaker connectors and an IEC power cord connector were added along the way. I ended up with a tube power amp that has only the power transformer, output transformer, output tubes and chassis in common with the originals.
The Dynaco factory was at one time about 3 blocks from my house. This was very convenient for me. I could get parts and assistance by walking around the corner. Add the reasonable price of Dynaco products and buying thier gear was a no brainer. At one time I had their entire product line stored in a closet. I've still got a mint stock ST-70 that I may do some work on. It hasn't been much of an issue as I've been using ESL's since the early 80's. ST-70's just don't have enough power for any ESL I've ever owned.
www.dynaco-doctor.com is a very good place to get kits mods and DIY instructions for virtually any Dynaco product.

[tin ear]

Thanks for your reply; that's all very interesting. Such easy access to Dynaco must have been a real hoot!

I'd say that since you are all set up with the MkIIIs, and aren't using the ST 70, you might want to offer to sell it to me. But I won't, as you say it is mint -- you could get a lot for it, more than I could pay. I have an ad on craigslist looking for old junkers for me to tinker with. Of course I need at least two at any given time, one of which is actually working & hooked up.

Thanks for the info. The more I find out about these amps the more I like it. I'm not all that savvy at electronics theory, but these things are pretty simple (as long as someone else has already done the brain work ).

[jrhymeammo]

Hi Tin, we havent seen you hear lately. How's your ol lady?

[tin ear]

Hi Tin, we havent seen you hear lately. How's your ol lady?

Hey, JRA, I've been busy finding, buying, and searching out upgrade parts for my new amp.

SWMBO's fine, but like someone said, the newness of the diamond would fade over time, and it is starting to. (Woke up this morning with a honey-do list next to my computer.) Knowing that that was sound advice, I've thrown all my free-time energy for the past three weeks into my new toy quest.

But hey, life is good: I now have a sweet-sounding (but with an ugly chassis) Stereo 70. Have a capacitor upgrade board and an upgrade driver board on the way. Also possibly another ST 70 in the works, but I don't want to speak too much about that yet, lest I jinx it.

SWMBO is off doing chores this morning, so I'm firing up the tubes.

[JoeE SP9]

Thanks for your reply; that's all very interesting. Such easy access to Dynaco must have been a real hoot!

I'd say that since you are all set up with the MkIIIs, and aren't using the ST 70, you might want to offer to sell it to me. But I won't, as you say it is mint -- you could get a lot for it, more than I could pay. I have an ad on craigslist looking for old junkers for me to tinker with. Of course I need at least two at any given time, one of which is actually working & hooked up.

Thanks for the info. The more I find out about these amps the more I like it. I'm not all that savvy at electronics theory, but these things are pretty simple (as long as someone else has already done the brain work ).

I've been toying with the idea of getting a pair of Apogee Studio Grands. They seem to be rather hard to find so I may have to settle for a pair of Studio Ribbons and build my own sub woofers. My other option is a pair of Acoustat Model 6's. I have a lead on a pair but the owner isn't sure he wants to sell. The Model 6's would allow me to get rid of my subs. They would need more than the 2 MK-III's for power. Ideally 2 pair of MK-III's would be nice but finding 2 more at a reasonable price may be difficult and then there's the mods I would need to do to make them like the ones I already have. My other option with them would be a stereo amp for each side. 2 Adcom GFA-555's would be a nice start.
The Acoustat option is the cheaper of the two choices. I'm leaning more toward that because I've been having a hard time keeping my checkbook in my pocket when I pass the local Porsche dealer and see the new Cayman. If I keep what I have or get the 6's I can still get the Cayman. Getting the Apogees would mean no Cayman because I'd have to replace all my power amps with Krells or Levinsons. If it turns out that way the folks here would get first shot at my tubes.
What are you using the ST-70 to drive? Worked ST-70's are some of the best sounding amps in existence. You are right about them being easy to modify.

BTW: My ST-70 has never been used. I bought it at the factory when Dynaco went out of business.

[tin ear]

Oh, man! Tough decisions. 'Fraid I don't have much in the way of good advice for you, as much of the gear you mention is so out of my range that I'm not familiar with it at all. The question is, can you live with your existing gear for a while until you get settled into a car payment routine? Then you could start adding gear again. My guess is that you probably need the Porsche. You'll work the rest out.

I'm driving PSB Image T45s (around 89 db eff.) with the ST 70 until I get around to getting something more efficient. The PSBs do pretty well, though. I have not yet found the need to turn the pre-amp up more than halfway, and even less than that is generally adequate.

[JoeE SP9]

No one needs a Porsche. In any case I would be selling or trading in my 1989 911. I have described it in the thread list your ride or something like that.
You should notice that every piece of gear I have mentioned is available used. In the case of the speakers the models I mentioned are available only used. Krell or Levinson or any other pricey audiophile brand will only get through my front door in a used condition. The Acoustat option with a couple of Adcom GFA-555's is not really expensive. Much less than a grand for the speakers and less than a grand for 2 GFA-555's. Considering that I would sell my current rear/surround speakers and their amps my out of pocket expenses would not be all that much.
The Apogee option would be expensive no matter how I managed my choices. The major expenses being new amps and the need down the line to get Apogees and amps for them for surround speakers. We must timbre match our speakers.