kt88s in a single rectifier?
- Thread starter brit84
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CaughtLikeFire
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Re: kt88s in a single rectifier?
that's what Bob @ Eurotubes does with DRs and 5150s. he insists that they run well and that the amps sound fantastic. but he does lots of crazy stuff. Integrated quads of KT77s and 6V6s (i.e., two 6V6 and two KT77 in the same amp), integrated quads of KT88 and KT66 :eyecrazy:
$10 says that the amp has a Eurotubes "kit" and that the circuit has not been modified.
my brain isn't going at full steam yet this morning, maybe glassman can enlighten here . . . isn't there a strain on a DR's (or SR in this case) power supply with those KT88s? is there a risk of more than just poor tone?
that's what Bob @ Eurotubes does with DRs and 5150s. he insists that they run well and that the amps sound fantastic. but he does lots of crazy stuff. Integrated quads of KT77s and 6V6s (i.e., two 6V6 and two KT77 in the same amp), integrated quads of KT88 and KT66 :eyecrazy:
$10 says that the amp has a Eurotubes "kit" and that the circuit has not been modified.
my brain isn't going at full steam yet this morning, maybe glassman can enlighten here . . . isn't there a strain on a DR's (or SR in this case) power supply with those KT88s? is there a risk of more than just poor tone?
Re: kt88s in a single rectifier?
Correct me if I'm wrong, but isn't the primary Z for a 6L6/EL34 OT a bit off for KT88s? It would seem that using KT88/6550 in a circuit designed for 6L6 also draws quite a bit more heater current...I have noticed that Eurotubes suggests a lot of slightly questionable tube swaps; maybe they work, maybe they don't over the long haul.
Correct me if I'm wrong, but isn't the primary Z for a 6L6/EL34 OT a bit off for KT88s? It would seem that using KT88/6550 in a circuit designed for 6L6 also draws quite a bit more heater current...I have noticed that Eurotubes suggests a lot of slightly questionable tube swaps; maybe they work, maybe they don't over the long haul.
glassman
Electron Herder
Re: kt88s in a single rectifier?
CLF, you may be right about that kit. As for the power supply being up for the long haul with KT88s...I think it would be ok; as long as the tubes are operating in control. That would be a trick without modification and the KT88s would have to be so off spec that I would question as to whether they even sound like a KT88 any more.
CLF, you may be right about that kit. As for the power supply being up for the long haul with KT88s...I think it would be ok; as long as the tubes are operating in control. That would be a trick without modification and the KT88s would have to be so off spec that I would question as to whether they even sound like a KT88 any more.
glassman
Electron Herder
Re: kt88s in a single rectifier?
Zerb, the swap on your amp was definitely attainable...then again, your Marshall has an adjustment pot in its bias circuit while the Boogie doesn't.
^^ if somebody like Bob selecterd the tubes properly everything it should work fine.. I used to run a set of 6L6s in my marshall that needed a bias Voltage well into el-34 range (well out of spec for a normal 6L6 BTW)
Zerb, the swap on your amp was definitely attainable...then again, your Marshall has an adjustment pot in its bias circuit while the Boogie doesn't.
glassman
Electron Herder
Re: kt88s in a single rectifier?
E, It's been my experience that a little too much emphasis has been placed on matching the OT Z to the tube being used. Remember, Marshall, during the Unicord days, sold amps in the US with 6550s and everywhere else with EL34s, they used the same OT in both. The only difference was the secondary tap that the feedback was sampled from...and this was for tonal reasons.
I do agree that the KT88 draws enough current to be a concern in a 6L6 designed circuit. I don't think it would fail outright but it may have a negative effect on lifespan.
E, It's been my experience that a little too much emphasis has been placed on matching the OT Z to the tube being used. Remember, Marshall, during the Unicord days, sold amps in the US with 6550s and everywhere else with EL34s, they used the same OT in both. The only difference was the secondary tap that the feedback was sampled from...and this was for tonal reasons.
I do agree that the KT88 draws enough current to be a concern in a 6L6 designed circuit. I don't think it would fail outright but it may have a negative effect on lifespan.
brit84
New member
CaughtLikeFire
New member
Re: kt88s in a single rectifier?
should I post my PayPal address?
unless the guy played the hell out of the amp and gigged regularly, it's probably no worse for the wear. just plan on buying a pair of EL34s or 6L6s right off the bat. you can use Mesa, Groove Tubes #5,6,or 7, or just contact a reliable tube vendor and tell them that the tubes have to work well in a Mesa Single Rec.
I'd go for SED Winged C EL34 tubes myself . . .
should I post my PayPal address?
unless the guy played the hell out of the amp and gigged regularly, it's probably no worse for the wear. just plan on buying a pair of EL34s or 6L6s right off the bat. you can use Mesa, Groove Tubes #5,6,or 7, or just contact a reliable tube vendor and tell them that the tubes have to work well in a Mesa Single Rec.
I'd go for SED Winged C EL34 tubes myself . . .
