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Marant 7c preamp diyzone project

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Josep said:
Thanks, but I think maybe this can be a best project than others.
PCB and power supply seems very good.

Josep



Maybe not. The 7C had a pretty good phono stage and a very mediocre line stage. Its claim to fame is based mostly on collectors value.

Four (4) caps along the signal?!! ECC83 follower!!! I bet it only sounds good with TFKs :)
 
Josep,

You better go with an Aikido from John Broskie at:
http://www.tubecad.com/2006/05/blog0064.htm

Choose your input tubes depending of the gain needed
and you'll get better results than the Marantz 7 preamp!!! ;)

Even without a PCB the results will be higher quality and bandwidth!!
And there are on Tubecad many PS's to choose from.

As Analog_sa said: " the Marantz 7 is good for his collector value,
not for his preamp stage... "
And most, avoid diyzone :smash:

Regards.
Alain.
 
Of all the preamps to copy, not that one!

...It's phono preamp isn't bad but the post volume control circuits are veiled. The Audio Research SP-3-6 is basically am offshoot of this. They both evolved from an original Westrex circuit which in some ways was superior to either the Marantz or the Audio Research.
 
gain is the problem

I had made one such preamp...through a chinese source. The problem is the gain...it is too much for my setup.

Any ideas on how the gain can be lowered ? Changing the output buffer valve to 12AT7 or 12AU7 does not seem to help much either...

Regards
Sandy.
 
Re: gain is the problem

sandy said:
I had made one such preamp...through a chinese source. The problem is the gain...it is too much for my setup.

You'd have to add a resistor network to attenuate the input gain. Its way too high when used with cd source.
Sorry, I can't recall the actual values as it was implemented successfully for a friend who complained that 3 clicks of the step attenuator (built in volume control) was already too loud.
 
My friends and I all built the Marantz M7 line amp as our reference for enjoying the music. We all using Tube Regulated Power Supply for B+ and stabilized 12Vdc for the filament supply.

The results are very remarkable and outstanding.

Besides, I also built another one using 12SL7 and 12J5 instead of the 12AX7 and 12AU7 for amplication and bugger. However, I need to tweak the bias for the 12SL7 to get good sound from it.


Johnny
 
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