EL84 alternative
There's really only one that doesn't reqire any changes, other than pinout (check your tube manual). The 6GK6 is perfect. I recommend GEs. Rca and Sylvania aren't nearly as good in sound quality. I've used them in several projects. They're tougher as well. The have 10% more plate wattage (voltage and current. They're also relatively cheap.
There's really only one that doesn't reqire any changes, other than pinout (check your tube manual). The 6GK6 is perfect. I recommend GEs. Rca and Sylvania aren't nearly as good in sound quality. I've used them in several projects. They're tougher as well. The have 10% more plate wattage (voltage and current. They're also relatively cheap.
I bought a bunch of them back when they were a 2 dollar tube, and have been using them in homebres and the little Magnavox amps for years. I get noticeably tighter bass when combined with the better EL84 OPTs like the Dynaco Z565. I found this thread while I was looking around to see if anyone was using 6GM5s on EL84 iron. They have that big fat bottle for better heat dissipation, and fit pretty nicely on the SCA35 boards. I think f I can find the right power TX, Ican get a significant power increase. Dynaco really rated their outputs conservatively in the 70, and I'm willing to bet they did in the 35 series as well. Anyone know of a beefier PT that would fit under the hood of the SCA? Triode has a nice one for stock use, ut I'd have to do some checking to see if it would have a chance with say 20 or 25 per? I hate the math part of this "Hobby".
I need to put our brain trust together here and come up with a PT to run these 6GM5s in this SCA 35. I'm trying to think of either a 7591 or 7868 amp that uses a stand up mount PT. I think that would be real close to what I need. Can anyone think of such an animal. All the 7591 and 7868 integrateds I'm thinking of use a "through chassis" type PT. Height might be the killer here in any regard, as I'm thinking the OE unit just barely touches the top case as it is. I have a scrap iron pile, and I'm probably going to end up going through it with a meter, piece by piece until I find a suitable candidate. I wonder if the new and improved trode SCA35 PT has enough oomph. Come to think of it, I have a homebrew with one of those PTs in it, so I could do some testing, and IIRC they are only about 100 bucks or so?
6gm5 is a 9pin base, more likely replacement with more power but is not so popular and scarce..https://frank.pocnet.net/sheets/084/6/6GM5.pdf
my first mono amp was a pp 6EM5 borrowed one tube from our tv set in the 60's.....
https://frank.pocnet.net/sheets/049/6/6EM5.pdf
https://frank.pocnet.net/sheets/049/6/6EM5.pdf
like a pentode should...i did not hear much difference....
i am one who is not relying on just the output tubes for sound,
i believe it is the whole amp when properly built that makes good sounds..
I agree. I also use the 6p15p in a PP EL84 amp. You will need to tie the suppressor grid, G3, to the cathode with the 6p15p. The EL84, and 6p14p are tied internally. A friend did a thorough test with the 6P15p and the EL84. It was comparable with his favorite EL84 tubes with the amplifier he designed and sells. You find great prices on the 6p15p tubes.
Sockets wired for the 6Π15Π (6p15p) accept the 6BQ5/EL84, without incident.
The crucial difference between the 2 types lies in the area of g2 toughness. The screen grid of the 6p15p is fragile. The 6p15p does fine, in pentode mode, if you regulate g2 B+ with a 0A2.As is frequently the case with Russian types, specimens with the EB (ev) suffix are superior.
It's for all practical purposes a 6AQ5/6V6 and therefore a fantastic tube. The goofy pinout is the only thing keeping it from being more popular in my opinion. Cheap too.
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I ended up with an external power supply with a Triad R-121A power transformer connected by an umbilical cable to my SCA-35. It provides 800V center tapped at 200mA. Also on the PS chassis is a nice low impedance choke meeting critical inductance for a choke input supply with 2 6AX4GTB rectifier tubes.
There is really no comparison to the SCA-13 with the stock transformer and the external power supply. The external power supply provides effortless dynamics and solid bass.
Just a note: the original and the replacement from Triode which I purchased are both rated at 180mA. I measured 200mA with both channels driven to full output with the Triode replacement transformer with a huge sag in the B+. One more thing: the original and Triode transformers run too hot to touch so removing that heat source is also beneficial.
this is a 12EN6 pp amp, with regulated G2,
i am very pleased with it...
i am very pleased with it...
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