PP Amp kits qua Dyna ST-70?

Downhome Upstate said:
Mike B said:
I started my valve journey with a K12-G kit, 8 Watt, PP pentode.  Sounded great.  Then bought a Dared I30, 16 Watt, PP 6L6.  Sounded better.  Neither sounded as good as the class A elekit 6L6 and the flea power zero feedback Stereomour sounds the best.

Someday, when I've run out of other things to do, I'll get a big push pull valve amp to try in the garage.  Or not as the case may be - :)
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Mike,

Yup, love my Stereomour w/the Orcas & a sub for small-group jazz, acoustic anything, vocals, etc. I was thinking tubes for a rock and roll amp b/c I'm just starting to get comfortable w/understanding vacuum tube audio circuits. But if tubes and rock 'n roll music is where I want to go, maybe I should be thinking Mainline and some new phones.

Mike
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Nevermind about getting a good rock 'n roll headphone/amp combo. Just tried my DT880/600's back from the warranty service shop & plugged 'em into my Crack/Speedball with the North Mississippi Allstars 'World Boogie is Coming' on the CD player. I won't be needing anything else headphone/amp wise.
 
I built a triode-electronics ST-70, before I discovered Bottlehead. The build manual is nowhere near as good as those produced here. I was my first try at DIY, and I would not recommend it for a first timer. But I do have it working and it is a good amp.  Mine is tuned down to 17 watts per channel (tirode mode not pentode). It sits like a trophy in my garage, not for being bad, but I found better.  ;D
 
Another option, just for kicks, is to pick up an actual original ST-70 and mod.  OT's are wonderful.  Put in a Triode Electronics power supply board to start just to be on the safe side and later replace the driver board with the flavor of your choice (I decided to put in a new board but one that used the original 7199 driver circuit in my original Dynaco ST-70).  Can put in a new power transformer and tube sockets if you want, tube sockets eventually is a really good idea.  Personally, I like refurbishing the old stuff when that is an option though the cost all in is probably about the same as a new kit when all is said and done.  Anyway, just a thought.
 
Paully said:
Another option, just for kicks, is to pick up an actual original ST-70 and mod.  OT's are wonderful.  Put in a Triode Electronics power supply board to start just to be on the safe side and later replace the driver board with the flavor of your choice (I decided to put in a new board but one that used the original 7199 driver circuit in my original Dynaco ST-70).  Can put in a new power transformer and tube sockets if you want, tube sockets eventually is a really good idea.  Personally, I like refurbishing the old stuff when that is an option though the cost all in is probably about the same as a new kit when all is said and done.  Anyway, just a thought.
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Yessir, absolutely. My preference, actually. More fun and probably a bunch more learning that way. I've taken to surfing all the area Craigslist sites for anyone who has an original ST70 for a decent price. Hard to find in the greater metro NYC/Philly area, tho'. Seems like the internet has everyone thinking that grandpa's old stuff is lost treasure.
 
Well, if you are willing to risk an untested unit on ebay... they are really cheap.  Saw one go for $200.  Shipping is a royal pain, $50 on average I guess, but then you have one in your grubby paws and can get to work!
 
I've said it before (maybe even here - apologize if I'm repeating myself) - a Dyna ST-70 is kind of like the Chevy Small Block of tube amps...lots of them out there, lots of aftermarket parts and pieces, and lots of tweak potential.  You can generally sell them for as much (or sometimes more) than you paid for them, and they sound pretty good.

I had a Dyna ST-70 at the heart of my shop system for a long time, and was very happy with it.

If you can get one for $200, that is a steal - they tend to go for more than that.
 
Might be a steal, but thus my preface that in that price range they are untested, so you take your chances.  But they do show up in the 2-300 dollar range as a quick sold search on ebay will verify.  My last Dynaco Grainger let me have (or sold to me so cheaply that it was the same thing) a Dynaco chassis.  Everything after that was then my choice.  Those can be had in the $75 range.  Then buy either vintage output transformers or new (I used Magnequest) and you start off with the a new PT and power supply board.  Anyway, there are enough Dynacos on ebay in various stages of undress that you can decide where you want to start and go from there.  And all the Bottlehead preamps I have used mated extremely well with my Dynacos.
 
Downhome Upstate said:
FWIW, I placed a couple of ads for ST-70 road kill (AA Trader & US Audio Mart), and now I will wait.
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At one time I was into handmade antique carpets (on the cheap end of the scale!!) - we call them "noble wrecks". Sometimes you just have to make a cushion out of the good parts of a worn-out rug.
 
I know this is the Bottlehead site, but since most of us here have a Bottlehead amp in addition to our Dynaco, for those who have one, so post your progress.  I have built one from the chassis up and rebuilt another and that was my entry into tube audio before Bottlehead.  So I will be very interested what direction you take as you go.
 
Paul Joppa said:
Downhome Upstate said:
FWIW, I placed a couple of ads for ST-70 road kill (AA Trader & US Audio Mart), and now I will wait.
Click to expand...
At one time I was into handmade antique carpets (on the cheap end of the scale!!) - we call them "noble wrecks". Sometimes you just have to make a cushion out of the good parts of a worn-out rug.
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I like that, Paul, altho' I had to stop for a minute and think it through. A cushion it will be, then.
 
Paully said:
I know this is the Bottlehead site, but since most of us here have a Bottlehead amp in addition to our Dynaco, for those who have one, so post your progress.  I have built one from the chassis up and rebuilt another and that was my entry into tube audio before Bottlehead.  So I will be very interested what direction you take as you go.
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Yup. I'm kinda doing this backwards. But better Nate than lever.
 
Just paid $300 + shipping for a functional ST-70 sans tubes and cage.  I missed out on a listing on DIY Audio for a Tektronix 2215. Maybe its time to look for another 'scope and some probes.
 
Sweet! The upgrade process begins. Check your bank account. As always, the can cap is the first thing to deal with. Then the driver board, then the old tube sockets, maybe a new power transformer...  Good luck!
 
Paully said:
Sweet! The upgrade process begins. Check your bank account. As always, the can cap is the first thing to deal with. Then the driver board, then the old tube sockets, maybe a new power transformer...  Good luck!
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Selenium rectifier?
 
Caucasian Blackplate said:
Paully said:
Sweet! The upgrade process begins. Check your bank account. As always, the can cap is the first thing to deal with. Then the driver board, then the old tube sockets, maybe a new power transformer...  Good luck!
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Selenium rectifier?
Click to expand...

How 'bout that stock GZ34 rectifier?
 
"Selenium rectifier?

Its between the power transformer and the PCB, for the bias. Replace it with a diode first thing...John
 
Paully said:
Sweet! The upgrade process begins. Check your bank account. As always, the can cap is the first thing to deal with. Then the driver board, then the old tube sockets, maybe a new power transformer...  Good luck!
Click to expand...

After I have a look under the hood, up close and personal-like, I was thinking about ditching the can cap. The Triode Electronics power supply capacitor board looks good. It mounts underneath one of the OT and has 500 uf of filtering. $77.
 
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