Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: guntherbuffalo on September 25, 2014, 03:10:52 pm
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Hi,
I am selecting parts to build a 6v6 Matchless Lightning type amp. I am looking at using a tweed deluxe or deluxe Output Transformer, and was unsure what OT primary would be best for the 6v6's. I think the Original Lightning using el84s had an OT with a 4k primary, but I have heard the recommended primary load for 6v6's is 10k. So which do I go for? 4k or 10k? Or somewhere in between like some of the 6.6k OTs? What would be the effect of using these differing primarys?
Thanks,
Paul
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EL84s are happy with 8K or 6.6K. So are 6V6s.
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Great thanks,
What differences in tone/loudness can be expected from using a 6.6k or 8k primary? Am I right in thinking this affects the wattage of the amplifier?
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What will the B+ be? Do you have a schematic of what you're planning to build?
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I have a Trinity TC15 that I built from a kit that has a switchable OT primary. (Matchless DC30 clone - a Lightning is basically this amp without the EF86 channel.) It uses only two EL84's but basically what it does is add a little more gain in one position while the other has slightly more clean headroom. There is also a volume change that you can definitely hear on the higher gain setting as well.
It switches between 5K and 8K on the primaries and for the life of me I can't remember which setting is which! The primary impedance is the only thing the switch "switches."
In short, it works kind of like a "lead boost" but not quite so dramatic a change as most "lead boosts." He calls it a "crunch/munch" switch... one of the settings is the Matchless impedance while the other is the VOX AC30 impedance.
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The B+ will be 250v at 0.12A. Using a solid state rectifier. The schem will be the same as the normal lightning schem, except for the rectifier, and the 6v6 cathode resistor which I will be changing to 250R/10w as it is in a deluxe. Everything else will be the same.