6550 tubes require more B+ current than the 6L6GC. Can your power supply handle that?
Question on 1959 Crown SXA tube amp power supply, switching noise from half wave rectifiers?? 120hz hum.
Plus, there are a lot of good 6L6GC tubes available. Prolly no need to spend the extra $$$ on 6550 tubes, just to run them conservatively.
There are some Russian tubes that are supposed to be very close to the specs, and also KT66, which might get me closer to the original sound.
Yeah, it was aware of the heater current. I just didn't know if it was doable... I had a feeling not, but then again. Thought there might be something out there. This here seems to be the new work-around. The Russian-made 6N3C-E. I'm gonna see if they are the same pin out. But apparently they are reaching the EL37 specs and are possibly drop in replacements.
6N3C-E has same pinout as the EL37. You must bias the Russian tube to 6L6GB standards (19 watts max) and not the 6L6GC (25 watts max). Class AB1, push-pull.
Crud... so I wonder what the real key is to this quandary? Any ideas? I plan on keeping this for a long time, firing my studio monitors. .. 2 JBL 4412A, and a pair of monster Allen Organ speakers from the late 70s. Those allen organs speakers are something else. Typically, they are full of peerless and JBL drivers... With absolute monster crossovers. Extremely well made cabinets... A bit on the long throw side though... But i've got a pretty big room... And they fill it up really nicely. The JBL's are awesome... And just for good measure. I have a pair of EV eighteen inch subs on either side... In a pair of tiny near field BOXES to a/b.
I'm completing a project I started with my late wife. So it's kind of important. And we did a ton of stuff! I may have To just bite the bullet and find some good EL37's.
This is some of our work here. There's probably about three times that total.
Buy some modern 6L6GC.Crud... so I wonder what the real key is to this quandary? Any ideas? I plan on keeping this for a long time, firing my studio monitors. .. 2 JBL 4412A, and a pair of monster Allen Organ speakers from the late 70s. Those allen organs speakers are something else. Typically, they are full of peerless and JBL drivers... With absolute monster crossovers. Extremely well made cabinets... A bit on the long throw side though... But i've got a pretty big room... And they fill it up really nicely. The JBL's are awesome... And just for good measure. I have a pair of EV eighteen inch subs on either side... In a pair of tiny near field BOXES to a/b.
I'm completing a project I started with my late wife. So it's kind of important. And we did a ton of stuff! I may have To just bite the bullet and find some good EL37's.
This is some of our work here. There's probably about three times that total.
The 6L6GC is rated for 30W plate dissipation. The 6P3S-E will manage at least 23W, same as a 5881. I read reports of it being run at 25W without showing color, but I haven't tried that myself.
Jack
I like to bias them lower. The 6P3S-E seems to have better headroom at a lower bias point.
This does have what appear to be some un-used windings on the transformer. If one of them is good for 6.3 volts at 3 amps or so, it could power one channel's worth of EL34 with no fuss. At that point its just a jumper from 1 to 8 on the output tube sockets and it will run an EL34 tube.
This seems like a possible best solution. Since it's ac, You can combine 2.
Supplies right? There are quite a few unused taps that have been taped off. Weather they were for unavoidable reasons or possibly upgrading the amplifier later? I don't know. For instance, the bias voltage supply comes from one transformer. But they are both identical and so one is unused. That may be a little bit high but... Also I believe that the heater supply is basically one tap for all the tubes involved. I think... There may be two I don't know. But there's a lot of them. So i'm sure one of them is probably going into the job. Would the KT66 do better than the EL34, and is the EL37 the better tube because of its current draw and transconductance? Just trying to get the highest fi, here, in a world where it is unlikely I'll find a matched quartet of EL37's. In my experience though, the EL34 is a very powerful tube, Since they often were switched off with 6550s in marshall amps
I'm using modern 6L6GC, at the moment. I don't think the transconductance is the same as the EL37's, though... I mean something had to make them different, I believe. In the current market they sell for about eight hundred dollars a pair... And that's general used! I guess i'm just trying to get what I would get logically out of those tubes as this built specifically for those tubes.
Are the sounds of the 6L6GC tubes not to your liking? Or are you just worried about the tube's specs?
If the sound is not to your liking, post what you'd like to hear or not hear. You may like another brand or subtype of the 6L6GC.
The specs are important. 6L6 transconductance is much lower than the EL37/EL34. That means the driver will have to swing more voltage for a given output power. Even if the driver is capable of achieving the same maximum output without clipping, greater swing creates higher distortion.Are the sounds of the 6L6GC tubes not to your liking? Or are you just worried about the tube's specs?
If the sound is not to your liking, post what you'd like to hear or not hear. You may like another brand or subtype of the 6L6GC.
Jack
Yeah i don't entirely understand the 6l6gc sub, other than the current draw issue. The socket jumper is a piece of cake.
Also honestly modern el34 are decent. My JJ act and sound very much like my old Mullard and they aren't dumb money.
If one of those extra windings is good for 6.3v, you're covered
Also honestly modern el34 are decent. My JJ act and sound very much like my old Mullard and they aren't dumb money.
If one of those extra windings is good for 6.3v, you're covered
I was reading and it looks like the closest thing I could get to an actual EL37 is the Gold Lion KT66... Which is expensive... But it looks like it's everyone's first choice for the closest thing to... I just don't trust anybody to sell me a quartet of EL37's in primo shape... I'm not sure that I would even know what that would be... Nor have the test equipment to let me know... Whereas the KT66 will at least be matched. I guess i'm just curious what those amps are supposed to sound like as opposed to what i'm going to get.. I can't really come in on the actual quality of the 6L6GC In this, yet. I'm gonna give that a try first, for sure... I'm just rebuilding the thing completely, at the moment. I managed to find all of the parts I needed except the bias pots are Only 10K. VS 15K.... But I think that's plenty as I barely tweaked. The 15k to get the needed voltage. It's a shame that the only multicap can that I could find doesn't have the locking tabs that the old ones had... So I swiped a couple of the CAP BRACES off of an old leslie cabinet amplifier from the SS ERA... They will require a couple of more screw holes, But will look good in the end I guess.Are the sounds of the 6L6GC tubes not to your liking? Or are you just worried about the tube's specs?
If the sound is not to your liking, post what you'd like to hear or not hear. You may like another brand or subtype of the 6L6GC.
This was my understanding. I like the way the GOLD lion KT66 stacks up. Sure, it's a bit pricey, but I think the Mullards were never cheap, as they were built for 10k hours! Plus I like the big bottles that these were made for. There is a certain visual factor... At least there is on mine! Lol. I have to say that the original face plate for this amp was about the most austere and boring sheet of aluminum i've ever seen. I think this was probably a prototype at the time. No model number or even logo to be found on the whole thing. Mine might be a little bit gaudy, But I think if I get that crown logo engraved, Possibly filled in with a color, And maybe "studio amplification" Underneath and smaller letters. That might kind of make the plexiglass look a little better.