What you supply: One McIntosh MC30 with good transformers and good tubes (except the 12AU7 and 12AX7 driver, which we replace). You pay shipping both ways, or deliver it and pick it up.What we do: - Replace every tube socket with ceramic sockets. - Install Russian paper-in-oil caps for all coupling caps. - Replace all resistors except the wirewounds with a mix of metal film and carbon film. - Install a choke for the power supply, which requires drilling holes in the top of the chassis (this is the only mod that is not fully reversible). - Replace the 12AU7 with a 6CG7/6FQ7 that tests new (black plate if we have it). - Replace the 12AX7 driver tube with a 12AT7 and replace the cathode resistors with values appropriate for a 12AT7. - Parallel the sections of the input tube and replace the bypassed cathode resistor with an LED. - Convert the rectifier to solid state UF4007. - Convert the bias supply to full wave solid state using UF4007s. - Install solid state current sources on the phase splitter and pre-driver tubes. - Replace all electrolytics, and vastly increase the power supply capacitance on B+ and C-, and convert B+ to C-L-C. The final capacitance stage is bypassed with film on B+ and C-. - Disconnect the input potentiometer, but leave it physically mounted. What’s extra cost: - Tubes, if needed (except the 12AT7 and 6CG7/6FQ7, which are included). - Transformers, if needed. Heyboer can rewind or replace power transformers, but they don’t do McIntosh output transformers. - If you want to specify brand/type of resistors or other items, you may supply them or we’ll source them for you. The Result: - The best-sounding amplifiers we’ve heard, top to bottom. This is an amp you’ll own for the rest of your life. Recommendations: - If you need output tubes, we recommend Russian reissues of American or European tubes. We’ve used those for several years and had no failures or bad-sounding tubes. Sylvania grey plate 6L6s are great in this amp. In the MC30 we do not recommend the otherwise venerable RCA black plate 6L6. We also do not recommend converting to 807. Options: - Install an IEC socket so you can choose the power cord. Cost is $100 and includes an average power cord. This requires enlarging the power cord hole already in the chassis so is not reversible. Notes: - All the mods we do are electrically reversible; that is, they can be undone and the amp restored to its original electrical state. The holes needed to mount the choke are permanent. - We don’t expect you read this ad, and just send your MC30 and a pile of money to us without discussion. Feel free to email or call. You can also audition a pair of modified amps at our shop in Omaha, NE by appointment. You are welcome to bring your own music (LP, SACD, CD or whatever) or listen to ours. FAQ: 1. That's a lot of money to rebuild/modify one amp! Yes, it is. 2. What if the output transformer is bad? We don't know, we haven't run into a bad one yet. 3. Can you use (insert brand) resistors or capacitors? Yes, you supply at no extra cost or we source at extra cost. 4. How do I know it's worth it? Make an appointment and come in and listen.
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