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MC 240 ReTube or Replace

About a year and a half ago I acquired an old McIntosh MC 240.

I replaced the capacitors and retubed it using:

Genalex Gold Lion 12AU7 gol

Genalex Gold Lion 12AX7 gold

Tube Amp Doctor TAD 12BH7

TUNG-SOL 7581A

 

Now after some 1,000 hours of operation, driving a pair of Salk SS 6m speakers, one channel will intermittently give out a blast of static within minutes of power up and blows the fuse. This leads me to believe I have a tube which may be intermittently shorting.

 

With the MC 240 being almost 60 years old I’m wondering if modern technology has surpassed it.

Thus, the question retube or replace it.

 

Currently my choices are:

Quick Silver 60 watt mono amps

Mc Gary Audio SA 1

Van Alstine Vision SET 400

 

I would appreciate any comments.

TNX



pelletfan
jond's avatar
jond
5,798 posts
 
Don't sell it retube it and if necessary do additional work on it, it's worth it.
tomic601's avatar
tomic601
12,911 posts
 
Fire sale is good, I need another to match my 1961.
Heavy gives good advice on swapping tubes.
you might consider having it gone thru by competent tech: Audio Classics, Terry Dewick, Mike Samea in Michigan can do a bang up modification w HK style regulation, Finally Randy Vikan at Elite Audio Tech on Key Penninsula in WA is fantastic.
Tube amps are dominated by sound of the transformer, find a better output than the 240 ???? Doubt it.
best to you
jim
pelletfan OP
14 posts
 
Yup the power section was replaced with the capacitors.My older than dirt back will NOT allow me to lug around a 60 lb amp these days....
There are internal and external fuses which have randomly blown and to do a lot of further testing I'm going to need to get a lot more of each fuse.........
This is causing my pore ole back to complain!

oldhvymec
5,101 posts
 
https://www.amazon.com/Extreme-Max-5001-5083-Hydraulic-Motorcycle/dp/B06XNZ5GV6/ref=asc_df_B06XNZ5GV...

:-)
holmz's avatar
holmz
2,328 posts
 
PM me to offload it cheap, and I help you out.
Alternatively it sounds like it could be a capacitor. Any decent tube person will likely be able to sort it out.
It could also be something with the speaker (like an XO cap), which is presenting a difficult load, or oscillation…
You could switch the RHS and LHS channels to ensure it is related to the amplifier channel.And also which the driving source like a CD player with different interconnects into the unit with LHS/RHS swapped.
I am not even 100% certain it is the amplifier. My amp was also bad until I found it was a bad set of interconnects… Not the ones that I had just soldered up, but the 5 year old store bought ones.
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