My final comment to this thread would be if you want to hear how this amplifier is actually intended to sound I would not modify it at all, the Jadis stuff is interesting sonically speaking.
Sorry that my recollection of servicing them is not what it should be, but it's been 21 years since I last worked on one, and a lot of things have happened in the intervening years.
Just don't be too quick to give up.
The level of contradiction is epic in this thread so I'm going to bow out now. Good luck Mark!
Sorry that my recollection of servicing them is not what it should be, but it's been 21 years since I last worked on one, and a lot of things have happened in the intervening years.
Just don't be too quick to give up.
The level of contradiction is epic in this thread so I'm going to bow out now. Good luck Mark!
i never ever used a bucking traffo, i design and built all of my traffos used in my projects....
there are other ways to lose some dc voltage is you want to, another way is added resistance at the secondary ac line to the rectifiers...
this and the dc resistance mods can be used alone or in tandem, there are many ways to skin a cat...
if you can post a schematic of the psu and dc resistance of the power traffo hv ac secondary, then more concrete suggestions are possible...
no one is stopping you if you want to use abucking traffo, it's your choice, but bear in mind that there are two ways you might end up with, one lower secondary ac and the other a higher hv ac, but this is not so catastrophic, just reverse the winding of the bucking and you are go...
in the end, your amp, your choice, do what you think you have the confidence of doing, this is after all DIY, where all ideas are welcome...
there are other ways to lose some dc voltage is you want to, another way is added resistance at the secondary ac line to the rectifiers...
this and the dc resistance mods can be used alone or in tandem, there are many ways to skin a cat...
if you can post a schematic of the psu and dc resistance of the power traffo hv ac secondary, then more concrete suggestions are possible...
no one is stopping you if you want to use abucking traffo, it's your choice, but bear in mind that there are two ways you might end up with, one lower secondary ac and the other a higher hv ac, but this is not so catastrophic, just reverse the winding of the bucking and you are go...
in the end, your amp, your choice, do what you think you have the confidence of doing, this is after all DIY, where all ideas are welcome...
I’ll have to think about this. I can post a schematic
Attachments
definitely R7, 4.7 can be increased....500ufd of filtering is huge...
if you can indicate the voltage readings on either side of 4.7 ohms, and see actual voltages...
now tell us how much voltage you want to lose....or what voltage you are comfortable with...
are the filament voltage reading within limits?
one disadvantage or reducing the primary voltage is you can end up with lower filament voltages...so all things need to be considered...
if you can indicate the voltage readings on either side of 4.7 ohms, and see actual voltages...
now tell us how much voltage you want to lose....or what voltage you are comfortable with...
are the filament voltage reading within limits?
one disadvantage or reducing the primary voltage is you can end up with lower filament voltages...so all things need to be considered...
Thank you Tony. I have to open up the amp again to get all the readings. I’ve been playing it a little bit. I will try to do it this week. It’s a huge and heavy monster, not easy for me to handle...
Now I have a worse problem: the preamp has began to motor-boat in MC phono. Not loud, but very annoying. It’s also a Jadis, their classic JP80MC, which I also had “a momentary lapse of reason to acquire”...
MC phono inputs have the highest gain.
Ground loops causing feedback may be suspect.
If the turntable and cartridge are near the speakers, there may be mechanical feedback.
Ground loops causing feedback may be suspect.
If the turntable and cartridge are near the speakers, there may be mechanical feedback.
Hi Tony
There is only about 30v coming out of the power supply. MC stage has its own dedicated wire. I suspect a blown regulator in PS. Without schematics not easy to find. But possible.
