JJ 6L6 observation

[12AX7]

Just kinda wondering about how these tunes are viewed by people. I have a amp i built for use with EL34 but lately have come to prefer it with 6L6. I have tried a few including winged C. Winged C EL34's are my fav and i've literally tried every new prod 34 out there and i can't stand the thought of using any of them instead of the C's. So when i went to 6L6 i figured winged C must be the way to go. But having access to several other 6L6 i tired them before i got some C's. Long story short, i really like the C's a lot, but i cannot get past the fact that i like the JJ's as much amd maybe a tad more ! This surprises me because I have tried many JJ's and never thought any of them except the 6V6 were anything more than mediocre to average. But the 6L6 seems to be better than anything else and at least as good if not better than the now legendary winged C. Si i'm really curious....anyone else feel the same, and if the JJ 6L6 well thought of ? It really sounds close to the C to me except it's smoother on the clean tones which is why i think i like it a tad more. .

[Ed_Chambley]

JJ's are hit or miss I have found.  Some amps really like them.  I have put some in a Bassman 6G6A and they sound really nice, but in a Super Reverb I prefer =C= if I am using new tubes.  It seems JJ's prefer higher voltage and SS rectification.  If you made a change from EL34 to 6l6 and kept the same OT the JJ may simply prefer the circuit.  My favorite is RCA 6l6GB and very close is the Philips GB as well.

[12AX7]

Yes, same everything cept bias of course. But the winged C 6L6 i would think would benefit in the same ways the JJ would in my amp. Don't get me wrong, the C sounds great. It's just surprising to me because they sound so close while JJEL34's sound literally 50% as good as the Winged C 34's in my amp. It's not even close.  On a side note i didn't change the OT because i asked and everyone seemed to think it didn't matter or could go either way so i should leave it as is. Otherwise i'd have gone with a different OT. I think 6L6 optimally want to see just a bit more than the 34's ad the OT goes, about 4k vs about 3.4k, right?

[Ed_Chambley]

JJ's are Russian tubes and are different in spec from old american tubes.  In my experience, 6L6 prefer 5k-5k9.  Should work ok with what you have.  The =C= are different in spec from JJ's, but still Russian as well.  I have no reference, but I think the JJ's are simply working better at 3.4k or 4k than the =C=.  This is very subjective as tone always is.  If someone prefers breakup over headroom what tubes they prefer will be different.  Wattage comes into play as well.  At what point does the OT begin to saturate and is the resulting compression desired?

For instance, I have a few Super Reverbs and they all are a little dull with JJ's, but in the bassman they are very lively, bright and open.  The =C= sound great in a Super, but are harsh in the Bassman and lose that round bass tone.  I also have a few sets of RCA 6L6GC and they do not sound any better in the bassman, but I have a AB763 head with a Mercury OT designed for a Supro which is 5k9 and the RCA's are the best, but it is pushed a little hard by the PT.  Closer to 60 watts which is over the spec for the OT, but it sounds great.  The only way I have found what is best is simply plug them in.

[12AX7]

What generally happens tonally as you raise the OT's primary? brighter? darker? By the way, i'm not talking about compression and all that, as i'm mainly playing them at home volume. Talkin 1-3 on the master, well before the output begin doing compression and distortion. I'm just talking about the tube's character before any of that. 

[birt]

Ed_Chambley, JJ's are not Russian. they are Slovakian.

[Ed_Chambley]

As core size and winding increases you will get a better low frequency but, you will get more leakage which will lose some highs.  Transformers do not have impedance on their own.  They have reflective impedance, but also power handling capabilities.  The impedance is determined by the tubes plate.

The idea is to have a transformer which does not limit, but has the capability to reproduce the Hz needed.  For instance, a OT capable of lower Hz will have a larger core and more watts will determine wire size on the bobbin.  This will allow for circuit design to determine what the amp will sound like and also push phase shifts below the usable Hz range, but there is a limit and if over-wound you will lose highs.

There are many exceptions and lots of people like to use slightly undersized OT's.  The compression of the Princeton is an example when reflected impedance is 8k.  Change it to a deluxe OT at 6k6 using 6v6 and it will add more bottom.  At least this has been my experience.  I am writing this from memory from reading the section on transformers in the

http://www.el34world.com/charts/Books/RDH4.pdf

And a discussion I have has with HBP.  I am sure I have a few things oversimplified, but this is what I remember and also what I have discovered in trying different transformers.  There is a simpler explanation I remember reading, I just cannot remember where.  A google search may help.

I know this sounds like dancing around your question, but it really is not.  I read many pages and experimented.  For instance, I have a 50 watt Marshall type amp with EL34's.  I put on a OT designed for EL34, but had a small core and had a noticeable increase in highs.  Did the same with a OT from a 100 watt el34 and the lower end tightened, but I had to increase the highs some.  It is really a balancing act.  I just got my hands on a Heybour, 50 watt but have not had the time to check it out.

[Ed_Chambley]

Ed_Chambley, JJ's are not Russian. they are Slovakian.

Sorry, you are correct.