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Tankpopper 8th October 2012 11:47 PM

TA 377A preamp
hey guys

i got this unit a few days ago and it seems that nothing can be found online! anyone know anything about this unit? or better - anyone got the schematics?

all the pots are alps blue and it seems in pretty good shape.. beside the balance pot - it is unbalanced! when centered, the left channel bairly puts out anything - both channel are balanced only when the pot is turned almost all the way to the right. i hope a simple clean up will solve this but im bracing for worst because most likely the problem is on the board itself.

other then that, a 220 transformer will be great (its 110 right now).

it does sound great!

here are some pics:

thank you all for your time and help!
Tank out.

Tankpopper 10th October 2012 02:31 AM

nothing? :/

ticknpop 10th October 2012 03:02 AM

The wiring to the balance pot is possibly wrong or maybe the pot is defective. The technical description doesn't really give enough detail and the pictures don't show enough to help you more than that.

AMV8 14th October 2012 08:51 PM

1 Attachment(s)
My pre amp is excellant. If yours is damaged it is well worth repairing - otherwise sell it to me. The amplifier is an all fet pre amp that is balanced and symetrical in design. it operates on +/- 30 volts.
If you are repairing be careful as it is an all fet pre amp.
This is an old amplifier and I found that the quality improved when I replaced the various electrolytic capacitors. The ones that are connected to the power supply rails I replaced with new 105 degree electrolytics. The caps in the signal path I replaced with polypropylene capacitors. This does require some mods to the circuit board as there is not much space for polypropylene caps.
The amplifier seems to be called the TA 377A or TA 388. The seem to be the samr or very similar. They were marketed by Mark 5 and by Sound Master Electronics. I attach a schematic.
I do have more info such as part numbers but they are out of date now however if you think it will help e mail on my internet address.

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