Hey everyone! new here and just wanted to say hi to everyone and talk about my new dynakit project. My dad gave me his old ST70 a while back, i decided to resurrect it and try and use it as a guitar amp.
the amp has problems though. i run out of physical range on the bias pot on one of the channels to get the voltage right. still sounds good though at first, but after the amp warms up and you start to really drive it it sounds as if its like phasing in and out or something. now as you can see in the pics, there was some modification done to this, my dad cant remember what it was for. the first one i see is the two (actually three) resistors going from the quad cap to the left take off socked on the front. the other is a secondary set of outputs that are wired from the quad cap (thru a resistor) and the output tubes (thru a cap). anyone know what these outputs may have been for?
its not in the greatest shape cosmetically either, so ive decided to go ahead and rebuild/restore it. the transformers all checked out, and i think i can get the chassis back to a respectable shape. Im not overly concerned about keeping it all original as much as i am about making it the most suited for guitar as possible. so im not against getting whatever kit/board i need to, new tube sockets, tubes, etc. not sure what would be the best way to go to use this as a guitar amp so any suggestions would be greatly appreciated.
idealy, what i would like to do is this. there is an accompanying PAS-2 he gave me as well. i would love to use that as well and have the whole setup for guitar. maybe wire the "special" input to accept guitar and then maybe get a reverb tank and patch it in somehow as a kind of effects loop using the tape out and then back into the spare? again, id love any input on this.
here are some photos to check out of what i have.
Thanks for reading my post everyone, any input would be greatly appreciated!
-jim







the amp has problems though. i run out of physical range on the bias pot on one of the channels to get the voltage right. still sounds good though at first, but after the amp warms up and you start to really drive it it sounds as if its like phasing in and out or something. now as you can see in the pics, there was some modification done to this, my dad cant remember what it was for. the first one i see is the two (actually three) resistors going from the quad cap to the left take off socked on the front. the other is a secondary set of outputs that are wired from the quad cap (thru a resistor) and the output tubes (thru a cap). anyone know what these outputs may have been for?
its not in the greatest shape cosmetically either, so ive decided to go ahead and rebuild/restore it. the transformers all checked out, and i think i can get the chassis back to a respectable shape. Im not overly concerned about keeping it all original as much as i am about making it the most suited for guitar as possible. so im not against getting whatever kit/board i need to, new tube sockets, tubes, etc. not sure what would be the best way to go to use this as a guitar amp so any suggestions would be greatly appreciated.
idealy, what i would like to do is this. there is an accompanying PAS-2 he gave me as well. i would love to use that as well and have the whole setup for guitar. maybe wire the "special" input to accept guitar and then maybe get a reverb tank and patch it in somehow as a kind of effects loop using the tape out and then back into the spare? again, id love any input on this.
here are some photos to check out of what i have.
Thanks for reading my post everyone, any input would be greatly appreciated!
-jim






