rowingcoach
Active Member
I got a nice Mcintosh c27 for my tube preamp! Everything works, and it sounds lovely... BUT there is a constant HISS/Static in the right channel. It is very low, but noticeable on quiet passages of music. Even when no audio is playing the hiss is there. It does not change volume as the volume is turned up. It only goes away when I turn the balance knob totally left channel. The left channel is totally silent! Very nice.
I have done the usual Deoxit to the spinning parts inside the preamp. No change at all. It must be in the signal path. The Power amp has no issues alone. The hiss is on ALL the inputs, Aux 1 and 2, phono and Tuner. I did not see if it was also on the Tape inputs.
(edit. I just checked and with Tape 1 or 2 pressed in the HIss is still present)
I seems to be a cap or transistor.
SO. I took it upon myself to fix it. I first did the Google method of seeing if anyone else has ever recapped or replaced parts inside a c27. Nope. Nobody. I searched high and low.
I then looked at the Service PDF and found the part numbers for the Transistors. Nobody else has identified the Transistors for that model. I did a check to see if ANYONE has found a replacement for those transistors. Nobody has.
SO.
I am starting a C27 thread. I know the C27 shares a similar layout to the c26, but they are not 100% the same.
In the next few days I will be posting Original part numbers, cap values, and taking feedback on what parts would be the best "fit" and replacement.
I have done the usual Deoxit to the spinning parts inside the preamp. No change at all. It must be in the signal path. The Power amp has no issues alone. The hiss is on ALL the inputs, Aux 1 and 2, phono and Tuner. I did not see if it was also on the Tape inputs.
(edit. I just checked and with Tape 1 or 2 pressed in the HIss is still present)
I seems to be a cap or transistor.
SO. I took it upon myself to fix it. I first did the Google method of seeing if anyone else has ever recapped or replaced parts inside a c27. Nope. Nobody. I searched high and low.
I then looked at the Service PDF and found the part numbers for the Transistors. Nobody else has identified the Transistors for that model. I did a check to see if ANYONE has found a replacement for those transistors. Nobody has.
SO.
I am starting a C27 thread. I know the C27 shares a similar layout to the c26, but they are not 100% the same.
In the next few days I will be posting Original part numbers, cap values, and taking feedback on what parts would be the best "fit" and replacement.
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