4x6V6 output transformer

[John_P_WI]

I am confident that with Mr Suhr's involvement with the new JK amps that they are an exemplary amplifier.

Interesting to note the low voltages on the first stage and the use of 1n914 diodes for limiting / biasing.

Thanks for sharing Mark.

[menger66]

I have a MM jimk-o output transformer i got off ebay a few years back for 60$, I really lucked out on it, it's a pretty impressive piece i iron, almost as big as marshall 50watt iron anyone know the specks of these MM does not list them.

[Colossal]

I have a MM jimk-o output transformer i got off ebay a few years back for 60$, I really lucked out on it, it's a pretty impressive piece i iron, almost as big as marshall 50watt iron anyone know the specks of these MM does not list them.

Mark,

Just email Patrick, he'll help you out.

[ToneMerc]

I knew the JK amps ran those 6V6s hot, just didn't know how hot. My 6V6 Plexi had killer tone running at 440VDC, but in some fairness to the tubes, the screens were lowered by 40V. It had JJ 6V6S and they took the beating just fine.

http://ampgarage.com/forum/viewtopic.php?t=20857

Scroll through to page 4, some comments straight from the man(JK)himself.

TM

[ToneMerc]

About 2 years ago I asked Jim Kelley - he's a member here - what he recommended in his amps that run 4x6V6 with 500V - NOS RCA and Sylvania was his answer. I have run used RCA 6V6A's in amps that had high B+ voltages and they work surprisingly well. Lucky I have a box of pulls, can't imagine what sellers want now for NOS RCA's.

Do you know what the screen voltages were under these conditions?

I'll have to dig up the Jim Kelley schematic but IIRC screen grids were near full B+. Yes, for tube longevity it would be a good idea for them to be lower IMHO.

Kitty Hawk also had a 4x6V6 combo run at 500V. Had to service one about 25 years ago, only tubes available were Russki & China blackened-glass 6V6's, they went up like firecrackers. I think I put in a pair of 6L6 and let it go at that.

I recall Brandon saying he ran a quad of JJ's at around 495V using one of the larger MM Dynaco type OT's and got 52 clean watts from them.

I experimented with running a JJ pair at 580 on the plates and 290 on the screens, it's a tough tube for sure.

TM

[Colossal]

I recall Brandon saying he ran a quad of JJ's at around 495V using one of the larger MM Dynaco type OT's and got 52 clean watts from them.

I experimented with running a JJ pair at 580 on the plates and 290 on the screens, it's a tough tube for sure.

TM

Bet that was interesting. Those Dynacos are killer OTs!

[JR88]

Did any of your JJ 6v6s go microphonic?

This pair I have left for now been trying to kill man...waay over dissipate, there rating is bullshit on dissipation..throwing some real current threw em......they do some great sounds. Telling you run them hard try to blow em up.

https://www.youtube.com/watch?v=tFcuN8y5ReY

[turbo5speed]

Well i delievered the amp after much testing and consideration. Shit happens but nothing makes me believe those 6V6 will fail anytime soon.

The OT is a 50 watter that, just by looking at him, i swear it can handle much more power.

Its sounding very good. When the owner makes the video i asked him, i will put the link right here.

Not sure if i like'em more as triode or pentode...