Manual
Hey Guys....
I know this an old thread, but I just offered a friend to fix his (the old type) Charisma pre with separate PSU. The torodial is totally burned, and the owner also is missing the manual and wants to know the settings of the dip-switches for the phono input. Anyone still able to supply schematics??? It would be a treat from heaven
.
Hey Guys....
I know this an old thread, but I just offered a friend to fix his (the old type) Charisma pre with separate PSU. The torodial is totally burned, and the owner also is missing the manual and wants to know the settings of the dip-switches for the phono input. Anyone still able to supply schematics??? It would be a treat from heaven
.Charisma 111 preamp
I need a manual that shows how to adjust gain,cartridge loading using the dip switches on an Mas Charisma111 pre..anyone able to help?
I need a manual that shows how to adjust gain,cartridge loading using the dip switches on an Mas Charisma111 pre..anyone able to help?
If anyone can assist, I also have a Metaxas Opulence on the bench. As usual with Metaxas products, everything runs too hot. The unit on the bench has an external, regulated power supply (Mains Isolated Power Supply), which appears to consist of an oscillator and power amp, which, in turn, drives another power transformer, which powers the preamp. I'm getting 53 Volts DC across the main filter caps, which are rated at 40 Volts. Oops. I need to figure out why the thing is operating at too high a Voltage.
I am prepared a reasonable amount for schematics.
TIA
Hi
Sorry to reply so late. I have sold the unit to a friend of mine, who thought he could fix it. But he was never able to get to it. So I may get it back
M
Hi marknoir,
I managed to repair a pair of solitaire amplifiers. But not until I redesigned them. You have just about every design problem going for you. If you fix one thing, another will get you.
Follow good design practice. I eliminated some stupid circuits, corrected some regulator designs to make them - regulate. I even had to make new "L" brackets for the power transistors. Two problems there. The transistors didn't line up to the PCB, and (you got to love this!) the swagged nuts sit proud on the mounting surface. You did want the transistors to touch the heat sink didn't you?
Finally, look at the specifications for the transistors used. In these things, the transistors had 30 VDC across them. That is, after the circuit powered up that is. These transistors were rated for ... 30 VDC.
It's okay to reduce the standing current to sane levels. The one thing I can't change is the lack of heat sink area to dissipate the heat! At least they wil turn on every time now and play music.
Oh, and by the way. They went from about 0.04 % THD down to 0.0025%, lower if you believe my HP 339A, but we are down to the residual at 0.002% and they both read 0.001%. Don't believe it. They sound a lot better too. I actually like the sounds that come out of them - now. They are soon to be reunited with their long suffering owner.
Do not buy these POS things. Poor design, terrible cosmetics and the need to re-engineer these designs. Only get involved with these if you feel the need to see just how badly a design can go sideways.
-Chris
I managed to repair a pair of solitaire amplifiers. But not until I redesigned them. You have just about every design problem going for you. If you fix one thing, another will get you.
Follow good design practice. I eliminated some stupid circuits, corrected some regulator designs to make them - regulate. I even had to make new "L" brackets for the power transistors. Two problems there. The transistors didn't line up to the PCB, and (you got to love this!) the swagged nuts sit proud on the mounting surface. You did want the transistors to touch the heat sink didn't you?
Finally, look at the specifications for the transistors used. In these things, the transistors had 30 VDC across them. That is, after the circuit powered up that is. These transistors were rated for ... 30 VDC.
It's okay to reduce the standing current to sane levels. The one thing I can't change is the lack of heat sink area to dissipate the heat! At least they wil turn on every time now and play music.
Oh, and by the way. They went from about 0.04 % THD down to 0.0025%, lower if you believe my HP 339A, but we are down to the residual at 0.002% and they both read 0.001%. Don't believe it. They sound a lot better too. I actually like the sounds that come out of them - now. They are soon to be reunited with their long suffering owner.
Do not buy these POS things. Poor design, terrible cosmetics and the need to re-engineer these designs. Only get involved with these if you feel the need to see just how badly a design can go sideways.
-Chris
Opulense
Hi Chris and thanks for reply
I don't have nearly as much knowledge in electronics and repair and redesigning... I would probably try to find somebody like you to work on it. I just thought it was the best solid state preamp that I have heard to date. And I have heard a lot. In any case, I don't think I am getting it back. But if I do find one, you can rework it for me, right?
;-))))
Rgds
Mark
Hi Chris and thanks for reply
I don't have nearly as much knowledge in electronics and repair and redesigning... I would probably try to find somebody like you to work on it. I just thought it was the best solid state preamp that I have heard to date. And I have heard a lot
. In any case, I don't think I am getting it back. But if I do find one, you can rework it for me, right?;-))))
Rgds
Mark
Hi Mark,
You would have to talk to me real nice. These are unpleasant to work on.
Have you tried a Counterpoint SA 2000 / 3000? These need some redesign, but at least they will be reliable once done. If I worked on the Metaxas, I might have to do some things that you wouldn't like. That means disabling some silly circuits and cutting the heat output considerably.
Try a Marantz 3650 or SC-9. Those are amazing preamps. These are based on the "diamond buffer" design. Some of the best headphone amplifiers and preamps are based on that technology. Marantz did it in the early 80's
-Chris
You would have to talk to me real nice. These are unpleasant to work on.
Have you tried a Counterpoint SA 2000 / 3000? These need some redesign, but at least they will be reliable once done. If I worked on the Metaxas, I might have to do some things that you wouldn't like. That means disabling some silly circuits and cutting the heat output considerably.
Try a Marantz 3650 or SC-9. Those are amazing preamps. These are based on the "diamond buffer" design. Some of the best headphone amplifiers and preamps are based on that technology. Marantz did it in the early 80's
-Chris
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