| ampage Tube Amps / Music Electronics |
For current discussions, please visit Music Electronics Forum. |
ampage archive
Vintage threads from the first ten years
dynaco mods
:
 6/14/1998 7:48 PM |
|
bill farris |
dynaco mods THE BARGIN OF THE DAY just purchased a dynaco st70 and pas3 preamp for $30 at a garage sale. it needs output tubes el34's i have several nos RCA 6550's can i use the 6550's,what mods would i need to do any replys would be helpful thanks bill farris 6string@dcr.net |
|---|---|
| 6/14/1998 11:13 PM |
|
| Jim S. |
Way to go, dude!! Sounds like an unbeatable deal. 6550's might work in that amp with a change in bias. You definitely should not just go ahead and plug them in - they'll most likely run way too hot, not sound right, and burn out quickly. I recommend you stick with EL34's, since those are what the amp was designed around. There are plenty of good, affordable choices these days for new manufacture EL34's, including Svetlana EL34S, Sovtek EL34WXT and Tesla (Czech) EL34. To get the best performance out of those components, they should also get overhauled inside. This would entail, at minimum, a general cleaning and tightening and replacement of all electrolytic capacitors, assuming the ones in there currently are the original ones (which will be fairly dried-up and not fully-functional after all these years). There could also be various resistors and signal capacitors that have drifted off value. You might even consider upgrading the resistors to modern low-noise metal film types and the capacitors to new audiofile-grade caps, even you feel like going hog-wild. Again, congratulations on scoring some great tube hi-fi gear for practically nothing. |
|---|---|
| 6/17/1998 1:07 AM |
|
| Steve A. |
Bill: Thought you might get a kick out of this photo of how NOT to build a ST70: Steve Ahola |
|---|---|
| Page 1 of 1 |