6L6GB/6V6GT combo vs a quad of 6L6GB or 6L6GC tubes

[sleepyguy24]

Hi everyone

Some time ago I got a Baldwin organ amp that was converted to a 2 channel stereo amp. I'm new to tubes and am in need of assistance.

The current tube complement on this amp is a pair of 6L6GB power tubes, a pair of 6V6GT power tubes, 3 12AU7 tubes and 1 5U4GB rectifier tube. It also has 3 transformers in the back.
The amp says Baldwin 6L6 and when I asked various tube experts around the net they were thinking it should run off of 4 6L6GB tubes. One suggested a quad of 6L6GC tubes.

Would it be a big difference in sound quality to go from the split of 6L6GB and 6V6GT tubes to 4 6L6GB/6L6GC tubes? The reason I ask is that I can't find any manuals about this amp and I have no idea on how to re-bias the amp. I went to a local music shop and they were wanting over $100 to re-bias and give the amp a thorough check. I'm happy with the amp but I have this nagging curiosity if there are more improvements to be found by making the change.

I’d be using this Baldwin amp with a pair of KEF Q300 speakers or a pair of KEF 103/3 speakers in a nearfield listening set-up. I think at most I'd be 6ft away from the speakers.

Another question that came up from reading various stuff on the net was how frequently do you have to re-bias a tube amp? I don't want to pay $ every couple of months to get this amp re-biased as it will always cost me a bit of change to do so.

Any thoughts/opinions/experience on all this is much appreciated.

Thanks again everyone.

[richidoo]

Even if the labels are the same, the construction of the tube can vary batch to batch. I think that it's essential to rebias the tubes when replaced, especially if the older tubes are vintage and very old. The old tubes could be US made, while the replacement are Russian or Chinese, totally different tubes. 

It's not hard to rebias the tubes, but if it means working in an open chassis with high voltage you really need to know what you're doing.

You could try new ones, they sound thin from underbias, or might runaway from overbias and blow up and take just a fuse. But they could damage something more valuable.

[sleepyguy24]

Hi richidoo

Thanks for chiming in. I'll keep in mind what you say about tube construction and rebiasing the amp when power tubes are replaced. I may have to bite the bullet and talk to a tech about rebiasing this Baldwin amp. Maybe they can show me and if it is easy enough I'll keep the amp. I don't want to damage something down the line.

Here is a picture of the amp. If any members know anything about it please don't hesitate to let me know. Thanks