JohnJ
Member
- Thread Author
- #1
As it’s been over two years, thought I’d give an update.
Firstly, I continue to enjoy the sounds made from these beasts; end all amps bar some sort of necessary downsizing down the road. Just turning 70, I certainly cannot see myself trading to anything larger, more powerful or expensive.
The output tubes used are the less conventional EL 509s made only by JJ Electronics in the Slovak Republic. Those included are branded “McIntosh USA.” I have found the sound to be more “neutral” compared to other McIntosh tube amplifiers with KT-88’s and prefer copper power cabling to silver plated.
The longevity of the 3500’s initial output tubes has been much lower than the KT 88’s in other Mc amps I’ve owned.
In the first few weeks of ownership, the left amp had a loud thud while shutting down. It was then fine for 16 months when it thudded on all shut downs. Swapping all output tubes on both amps, the thud moved to the right amp and from there I isolated and replaced the bad tube.
All was fine for a few months until intermittent thudding began from time to time on the right amp. McIntosh thought it might be "a tube shorting a component on the main PCB." Before embarking for Binghamton, I re-seated all the tubes solving the problem.
A few months later the left amp thudded on shut down and would not turn on. I surmised output tubes and replaced the entire set (8) with JJ’s purchased from Eurotubes.com in Oregon. They deal with JJ Tubes, tested several times and burned in for 24 hours. All eight were matched and $64 each opposed to the Mc branded at $134 each. The amp has worked fine since.
Eurotubes offering a very complete reasonably priced testing service found two of these original tubes to have shorts, one cold, one hot. The cold can be observed with a continuity tester, the hot short only while the tube had current running through it. The other six were had 35% to 45% life remaining. Not long after, the right amp began to act up. Fortunately, the six spares tided me over until I received another matched set from Eurotubes.
Since, both amps have been fine. Testing all Mc tubes again, six developed hot shorts but eight still have some life remaining. Spare Set! As a side note, one of the amps original sets had all McIntosh “red marked” tubes, the other “green marked.” Mention has been made by a fellow on another audio site that the green tubes were of a higher quality. In my experience, the reds were more reliable.
Recently, just to be silly, I replaced the driver tubes (3-12AX7A & 1-12AT7) with JJ E83CC & ECC 81 Gold Plated, balanced and matched. The sound is fuller, better balanced and more room filling. Not an earth shattering amount but noticeable.
Firstly, I continue to enjoy the sounds made from these beasts; end all amps bar some sort of necessary downsizing down the road. Just turning 70, I certainly cannot see myself trading to anything larger, more powerful or expensive.
The output tubes used are the less conventional EL 509s made only by JJ Electronics in the Slovak Republic. Those included are branded “McIntosh USA.” I have found the sound to be more “neutral” compared to other McIntosh tube amplifiers with KT-88’s and prefer copper power cabling to silver plated.
The longevity of the 3500’s initial output tubes has been much lower than the KT 88’s in other Mc amps I’ve owned.
In the first few weeks of ownership, the left amp had a loud thud while shutting down. It was then fine for 16 months when it thudded on all shut downs. Swapping all output tubes on both amps, the thud moved to the right amp and from there I isolated and replaced the bad tube.
All was fine for a few months until intermittent thudding began from time to time on the right amp. McIntosh thought it might be "a tube shorting a component on the main PCB." Before embarking for Binghamton, I re-seated all the tubes solving the problem.
A few months later the left amp thudded on shut down and would not turn on. I surmised output tubes and replaced the entire set (8) with JJ’s purchased from Eurotubes.com in Oregon. They deal with JJ Tubes, tested several times and burned in for 24 hours. All eight were matched and $64 each opposed to the Mc branded at $134 each. The amp has worked fine since.
Eurotubes offering a very complete reasonably priced testing service found two of these original tubes to have shorts, one cold, one hot. The cold can be observed with a continuity tester, the hot short only while the tube had current running through it. The other six were had 35% to 45% life remaining. Not long after, the right amp began to act up. Fortunately, the six spares tided me over until I received another matched set from Eurotubes.
Since, both amps have been fine. Testing all Mc tubes again, six developed hot shorts but eight still have some life remaining. Spare Set! As a side note, one of the amps original sets had all McIntosh “red marked” tubes, the other “green marked.” Mention has been made by a fellow on another audio site that the green tubes were of a higher quality. In my experience, the reds were more reliable.
Recently, just to be silly, I replaced the driver tubes (3-12AX7A & 1-12AT7) with JJ E83CC & ECC 81 Gold Plated, balanced and matched. The sound is fuller, better balanced and more room filling. Not an earth shattering amount but noticeable.
