My boss bought a C24 preamp to go with the quasi MC275 clone I built for him 6 years ago. A C24 is cheap compared to other McIntosh gear, he got it for $404 with shipping. He has a golden ear and decided it sounded not all that good, but it could be made to sound good for a song, but the next song would have to be adjusted. He decided he would like it to be tubed. The circuit is very close to the MX110 of the same era, but it seems that McIntosh just replaced the tubes with transistors; like they used the same 1M bass and 500K treble pots. The C24 also has a hiss to it, even though it uses a double volume control, with a volume control just before the tone controls, and a volume control just before the output connector.
He wants the tone controls, and I would like to leave as many controls intact as possible; like the HF, LF filters and loudness.
So I'm wondering, I could just tube the tone controls with a 12AX7 on each channel with one side for gain and the other as a buffer, leave the phono preamp transistorized, and then put in a 12AX7 on each channel with one side for gain through the filters and tone control leaving me about 10db overall gain, and the other for a buffer out.
The C24 has concentric tone, balance, and loudness controls. I found some Fender either bass amps or bass guitars that use the same controls almost. http://www.guitarpartsresource.com/imag ... 36-000.jpg
It's 100K so I could put in Morgan Jone's tone control, or Sy's tilt control, since my boss owns a Quad 34.
What should I do?