Variation on the JC-2 preamplifier

[carlmart]

There's a quite similar thread discussing the JC-2 preamp, where I'm rising other questions:

Need to build JC 2 preamp

These are not threads opened by me, so I can't ask to join them. But I also do not want to ask similar questions for the JC-2 preamp on both threads.

This thread seems to be concentrated right now on the Line Amp. But I think the other one is also considering the whole preamp project, including external parts (never mentioned here) and a phono preamp.

The parts I'm talking about are here around the Output Amp.

On the newer JC-2 versions there is LR01 (3K3) and LR4 (10K), which are the gain resistors. On the original JC-2 those gain parts were external, involving a balance switch and also a 2uF capacitor.

Should we disregard those parts on this project?

[whaleman]

Originally Posted by carlmart

...

Should we disregard those parts on this project?

Probably disregard them in terms of the discussion of the JC-2 design and its variants as has been the topic so far...JMO

[carlmart]

Originally Posted by whaleman

Probably disregard them in terms of the discussion of the JC-2 design and its variants as has been the topic so far...JMO

Not quite. Two components are important and what better values to use should be mentioned:

1) Input volume pot.

2) Output capacitor (if any).

[lbstyling]

Originally Posted by john curl

You will find ALL Parasound power amps and preamps made this way for the last 15 years.
.

If only parasound power amps sounded good!

I owned a halo a51 that I bought based on reviews ive read- horrificly high noise floor, floppy bass- slow sounding, lack of general detail. Id have thrown it away if it didnt cost so much.

Sold it for twice what I payed though

[tfender]

I Am OK Very Good Sound

[tfender]

I Am OK Very Good Sound

[apassgear]

Nice work tfender, looking forward to hearing more comments on sound appreciation.
Which transistors did you use?

[tfender]

Originally Posted by apassgear

Nice work tfender, looking forward to hearing more comments on sound appreciation.
Which transistors did you use?

I Use
2SK170BL & 2SJ74BL and BC546B , BC556B

[tfender]

Originally Posted by apassgear

Nice work tfender, looking forward to hearing more comments on sound appreciation.
Which transistors did you use?

the sound in the overall image that me hears , waste matter greedy omen clean peacefulness , distinctness , , , and , Impack , in frequency low section is the thing that me impresses very ,

[apassgear]

Good to hear you are impressed... Soon I will build mine starting from a kit...but also have a layout to use the venerable Toshiba 2SK389 and 2SJ109 at the input plus other Toshiba's on the output. The layout includes cap multipliers for each polarity on each channel, as per JC suggestions.
I have all the transistors etc except the PCB which I'm a bit lazy to etch.

cheers, Tony