you are probably right, i got those estimates from the RCA handbook, i am not looking to use these tubes single ended, like SY, i am a push-pull kinda guy...😀
btw, the RCA tube manual gives -Vg = (Vp x 0.63)/mu
i use this formula a lot when i want to find out which cathode
resistor to use...
AJT:
Thanks for the pics and info. I wonder how they are able to withstand 1000V peak between the g2 and g1 pins? De-rating them some does sound like a good idea.
The 6LW6 makes for some beautiful triode curves too (below), but as George mentioned, they can't be trusted in HV triode mode. They like to run-away.
Thanks for the pics and info. I wonder how they are able to withstand 1000V peak between the g2 and g1 pins? De-rating them some does sound like a good idea.
The 6LW6 makes for some beautiful triode curves too (below), but as George mentioned, they can't be trusted in HV triode mode. They like to run-away.
Attachments
smoking amp, i love those even spacings, proof of linearity....
the 8045g's were given to me probably my mistake,
the owner inherited the tubes from his dad who passed away a few years back...
i am trying to find out from him if he has some more in his stash,
the guy has 845 tubes, and spare power and OPT's for antique sounds lab amps
and luxman kits too....
he is selling those, it seems he has a housefull of these items...
the 8045g's were given to me probably my mistake,
the owner inherited the tubes from his dad who passed away a few years back...
i am trying to find out from him if he has some more in his stash,
the guy has 845 tubes, and spare power and OPT's for antique sounds lab amps
and luxman kits too....
he is selling those, it seems he has a housefull of these items...
i will make the psu in such a way that i can increase cathode current and plate voltages if i desired it....
hello
i recently repair two luxmann amp, one modified for GEC KT88 the other was original 8045G triodes.
this tubes are very nice the amp but with GEC KT88 or svetlana C 6550 give 30watts+-
the only modification was lowering negative bias supply and resistor from anode to G2 and something on feedback network.
the original 8045G 50 watts!!!
-grid bias was higer and no G2, triodes.
my customer have 12 of this tubes so i can use the best ones.
i think was made from TV swing plate , i have photos of this beautyfull amps
i recently repair two luxmann amp, one modified for GEC KT88 the other was original 8045G triodes.
this tubes are very nice the amp but with GEC KT88 or svetlana C 6550 give 30watts+-
the only modification was lowering negative bias supply and resistor from anode to G2 and something on feedback network.
the original 8045G 50 watts!!!
-grid bias was higer and no G2, triodes.
my customer have 12 of this tubes so i can use the best ones.
i think was made from TV swing plate , i have photos of this beautyfull amps
Attachments
8045G is closer to a TV sweep tube. A 6LW6 with a cooler (lower gm2) screen grid. The 6LW6 Mu is like 3.7, instead of the 4.5 (more like 5.0 actually) of the 8045G. Probably a necessary mod. to increase the grid 2 voltage rating for triode use.
Smoking amp is correct the 8045 is based on a sweep tube.
I have modified the LUX 3045 to KT88 or 6550’s the amp was designed by Tim Paravicini, the amp has much less power with KT88.
You can sell the 8045 for lots of money on EBay; best to sell them?
Apparently the Russian CERAMIC TRIODE 3cx300a is the best match, would be a very difficult TO MODIFIE THE Lux 3045 with fans and sockets for ceramic triode. And 3CX300’s are very hard to find now.
I bought my 3CX300’s when Russian tubes were cheap on Ebay and made an amp 40 watts class A You can get 600 watts from the 3CX300a lots of high powered noisy fans
Smoking amp is correct the 8045 is based on a sweep tube.
I have modified the LUX 3045 to KT88 or 6550’s the amp was designed by Tim Paravicini, the amp has much less power with KT88.
You can sell the 8045 for lots of money on EBay; best to sell them?
Apparently the Russian CERAMIC TRIODE 3cx300a is the best match, would be a very difficult TO MODIFIE THE Lux 3045 with fans and sockets for ceramic triode. And 3CX300’s are very hard to find now.
I bought my 3CX300’s when Russian tubes were cheap on Ebay and made an amp 40 watts class A You can get 600 watts from the 3CX300a lots of high powered noisy fans
thanks, multi, even the japanese 6ac10 triodes looked like tv sweep tubes looking at the innards...
Claudiomas
The MQ3600 and A3600 look very well made are they point to point wiring? All the Lux 3045’s I have seen need the PCB’s replacing not even Fibre glass look like a PCB from a cheap radio; I had the PCB’s copied and made from fibre glass.
The MQ3600 and A3600 look very well made are they point to point wiring? All the Lux 3045’s I have seen need the PCB’s replacing not even Fibre glass look like a PCB from a cheap radio; I had the PCB’s copied and made from fibre glass.
I was going to ask Tom Tutay of Transition Audio Design if he thought the MQ3600 was a modable amp to another triode tube such as a 300B. I don't know. I'm not too Into KT88. Maybe a KT150. It sounds like Multi has done a few. Are there other tube choices if your willing to look more at the transformers and chokes as the value. Maybe save some smoothing caps. Install new signal caps like VCap or Jupitor Copper foil beeswax. Or, just start from scratch and get Lundal transformers.
The Chinese make 6CA10's quiet expensive; have not bought any worried about the quality.
Even more difficult to replace than the 8045 as the 6Ca10 has 50 volt heaters. some people have tried EL34 with a very big reduction in Power.
I don't have any Lux amps myself, but several of my friends have.
Even more difficult to replace than the 8045 as the 6Ca10 has 50 volt heaters. some people have tried EL34 with a very big reduction in Power.
I don't have any Lux amps myself, but several of my friends have.
i have a quad of the 6ac10's and a pair of 50ca10's NIB, only NEC made those...the china versions are about U$75 each....
Gone into resurrect-mode... 🙂
A big sweep with the Pentode Retaliation circuit should be able to give the right triode mu. No worries about over voltage-ing the screens as at idle/DC it is a pentode. AC operation gives some darned fine triode curves...set the mu with the right FB resistors.
Douglas
A big sweep with the Pentode Retaliation circuit should be able to give the right triode mu. No worries about over voltage-ing the screens as at idle/DC it is a pentode. AC operation gives some darned fine triode curves...set the mu with the right FB resistors.
Douglas
Pentode Retaliation:
The UnSet scheme (local N FDBK, cathode drive ) used above with a big Sweep pentode should allow emulating most any big triode, usually with better curves too.
As a side thread from the original one for the Push-Pull ( Shunt Cascode Driver meets UNSET for Push-Pull ), I post here a preliminary version of a pentode-driving-a-pentode single ended amp with a DF of 8.6 (Zout is 0.93 Ohm considering 0.2 Ohm of secondary winding) without any gnfb, and capable of 30Wrms with 1.34% THD.
The driver is a pentode CCS loaded with a-g1 feedback, whilst the output is a pentode with a-g1 feedback plus the same amount of UL.
I've used this transformer as...
The driver is a pentode CCS loaded with a-g1 feedback, whilst the output is a pentode with a-g1 feedback plus the same amount of UL.
I've used this transformer as...
The UnSet scheme (local N FDBK, cathode drive ) used above with a big Sweep pentode should allow emulating most any big triode, usually with better curves too.
Oh, for actual Sweep tube outputs, one would use a lower fixed +Vg2, rather than the UL mode shown above, due to the lower Vg2 ratings for Sweeps.