if anyone still cares...
the two trannys in this pre mentioned earlier are just there to switch the ouput relays on, as andrew t correctly guessed.
the cause of the noise is definately the dil mosfets, which are in circuit for the buffered output.they are not used as switches, but for gain (oh mine are labelled zvn4206e).
there are 4 of these in total, and they are not in cct when using the passive out.
its a noisy design, but it sounds nice.
the pot is a 50k log btw.lm394s in the phono stage.weird mosfets for the pre amp buffer. all ac coupled with loads of expensive polyprop caps.
pretty sure its a tim de p design, hence its rather non-standard.
the cd section has far too much gain too i think.
the two trannys in this pre mentioned earlier are just there to switch the ouput relays on, as andrew t correctly guessed.
the cause of the noise is definately the dil mosfets, which are in circuit for the buffered output.they are not used as switches, but for gain (oh mine are labelled zvn4206e).
there are 4 of these in total, and they are not in cct when using the passive out.
its a noisy design, but it sounds nice.
the pot is a 50k log btw.lm394s in the phono stage.weird mosfets for the pre amp buffer. all ac coupled with loads of expensive polyprop caps.
pretty sure its a tim de p design, hence its rather non-standard.
the cd section has far too much gain too i think.
Hey all,
I just bought myself a 3A preamp to partner with my P140 power amp. This setup is working perfectly and is sounding good. However, I am planning on recapping both units, since they're both old enough for that. I was thinking if somebody has the schematics for either one of them, specially the preamp 3a. Does anyone know which caps are crucial for better sound? I want to replace the caps in the audio signal path for audio-grade polypropilene capacitors. Thanks.
I just bought myself a 3A preamp to partner with my P140 power amp. This setup is working perfectly and is sounding good. However, I am planning on recapping both units, since they're both old enough for that. I was thinking if somebody has the schematics for either one of them, specially the preamp 3a. Does anyone know which caps are crucial for better sound? I want to replace the caps in the audio signal path for audio-grade polypropilene capacitors. Thanks.
caps
hi,
i have one of these units.
your pre3a should be chock full of big yellow audio polyprop caps anyway.
all the ones ive seen are.
the unit is ac coupled and has about 25-30 big caps from memory.
i took some of these out to measure and they were perfect, so i've never changed them.
i did replace all the electrolytics a few years ago, theres not many and its easy to do. the preamp doesnt run hot so the caps dont age too badly.
let me know how you get on.
the amp has an audible hiss which is down to the weird dil mosfets in the active stage, but i think it sounds great despite the slight hiss.
i have been after a diagram for this amp for years - no one seems to have one!
hi,
i have one of these units.
your pre3a should be chock full of big yellow audio polyprop caps anyway.
all the ones ive seen are.
the unit is ac coupled and has about 25-30 big caps from memory.
i took some of these out to measure and they were perfect, so i've never changed them.
i did replace all the electrolytics a few years ago, theres not many and its easy to do. the preamp doesnt run hot so the caps dont age too badly.
let me know how you get on.
the amp has an audible hiss which is down to the weird dil mosfets in the active stage, but i think it sounds great despite the slight hiss.
i have been after a diagram for this amp for years - no one seems to have one!
There is another thread here at diyaudio where all aspects of the circuit are deepened. And, I repeat: the hiss can not be solved, they are part of the mosfets used. Don't let you fool yourselves by beter power transformer and fancy caps: this will do nothing at all with the hiss. Only a completely different power supply arrangement does influence the amount of hiss but in no way as to be gone.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.