Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: kasperbergholt on March 03, 2024, 09:57:33 am
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Clever people,
A while back I got excellent feedback regarding 6P3S-E output tubes (https://el34world.com/Forum/index.php?topic=30879.msg340253#msg340253), so I thought I share a question more.
By coincidence (when taking some photos of the amplifier) I noticed that my CS-600 has come with a 6DN3 damper tube (https://bergholt.net/6dn3) installed from the factory.
I was of the impression that the model uses af 6CJ3 tube, as this is mentioned in reviews and on Leben's official site.
Does someone know the reason behind this? And, in addition, if 6CJ3 tubes can be used without any issues?
In the folder that came with my amplifier (produced around 2007) the tubes are stated as: 4 X 6L6GC (5881) + 4 X 6CS7 + 1 X 6CM3 (6CJ3), which adds to the the confusion as they 6CM3 is equivalent to the 6DN3, and not the the 6CJ3.
I'm aware that the tube configuration in the CS-600 and the CS-600X are different. My question here only relates to the CS-600.
I've looked up both tube varieties on Radiomuseum, and there are differences:
6CM3 (6DN3) - 2.5 ampere; plate dissipation 12; average plate current 400.
6CJ3 (6CH3)- 1.8 ampere; plate dissipation 6.5; average plate current 350.
I'm in doubt as how to interepret this. Would the lower figures for plate dissipation & average plate current mean that the 6CJ3 is the more 'conservative' choice?
Huge thanks in advance,
Kasper
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Hello again :)
A brief update.
I've been in contact with Leben and have good news. Both the CS-600 & the CS-600X are compatible with both of the types mentionedin the original post. That means the following can be used: 6DN3, 6CJ3, 6CM3, 6CH3 & 6DW4B.
NOTE - this might not be the case in other products / designs / use-cases!