A year or two ago I was fortunate enough to come across a McIntosh MC225. Only problem was it blew fuses when trying to power up. On the shelf it went for a later date.
In the meantime Local friend offered a trade for it that I bit on. As part of the trade we agreed that I'd replace the power supply and bias components and other key items later when he got them. He ended up getting a very nice AuthentiCap kit for the PS/Bias supply and I had a few Orange drops and a CL90 around to complete these areas. I installed, we turned it on and checked bias and voltage. Everything was dead on and solid. He took the amp home to enjoy.
While he had it he replaced the RCA's, the input pots and the .01uf input caps (with Orange drops). Things worked out and I ended up with the 225 back in my possession. This time it occurred to me that it's karma that I have this amp so I decided it would be best to replace the rest of the component in the amp.
I ordered Sonicap's to replace all the film caps in the amp. I used Blackgates for the two 100uf@10v caps. I replaced all the resistors with 1/2 watt, metal film, 1% resistors accept for the few 1 watt resistors which I replaced with metal oxide resistors that I matched. Ceramic caps were replaced with silver mica caps. Top Hat diodes and one previously installed 1n4007 replaced with Vishay UF4007's. I also bought a quad of new EH 7591's.
I finished replacing everything late last night. This morning I tubed the amp up and brought it up slowly on the variac. After letting it stabilize for a few minutes and not seeing any red plating tubes, I took voltage readings and checked bias. Bias was a solid -21vdc across all four tubes. All voltages were spot on. I took off the dummy loads and hooked up the test speakers. I brought it up but had no sound in the right channel. I quickly saw a resistor touching something it should not be, moved it and had sweet sound.
I've been listening to it most of the day and I have to say I've never heard my speakers sound so good. Excellent sound across the spectrum so far. Interested to see how things turn out with a few more hours on it. This one should be ready for the next 30 years or so...
In the meantime Local friend offered a trade for it that I bit on. As part of the trade we agreed that I'd replace the power supply and bias components and other key items later when he got them. He ended up getting a very nice AuthentiCap kit for the PS/Bias supply and I had a few Orange drops and a CL90 around to complete these areas. I installed, we turned it on and checked bias and voltage. Everything was dead on and solid. He took the amp home to enjoy.
While he had it he replaced the RCA's, the input pots and the .01uf input caps (with Orange drops). Things worked out and I ended up with the 225 back in my possession. This time it occurred to me that it's karma that I have this amp so I decided it would be best to replace the rest of the component in the amp.
I ordered Sonicap's to replace all the film caps in the amp. I used Blackgates for the two 100uf@10v caps. I replaced all the resistors with 1/2 watt, metal film, 1% resistors accept for the few 1 watt resistors which I replaced with metal oxide resistors that I matched. Ceramic caps were replaced with silver mica caps. Top Hat diodes and one previously installed 1n4007 replaced with Vishay UF4007's. I also bought a quad of new EH 7591's.
I finished replacing everything late last night. This morning I tubed the amp up and brought it up slowly on the variac. After letting it stabilize for a few minutes and not seeing any red plating tubes, I took voltage readings and checked bias. Bias was a solid -21vdc across all four tubes. All voltages were spot on. I took off the dummy loads and hooked up the test speakers. I brought it up but had no sound in the right channel. I quickly saw a resistor touching something it should not be, moved it and had sweet sound.
I've been listening to it most of the day and I have to say I've never heard my speakers sound so good. Excellent sound across the spectrum so far. Interested to see how things turn out with a few more hours on it. This one should be ready for the next 30 years or so...
