What tubes for a 5150III 6L6 50W?

[Rex Rocker]

Wondering what you guys like in your 50 watters.

I'm thinking Chinese all throughout the preamp, Sovtek LPS in the phase inverter, but what about 6L6's? I'm curious about Sovtek 5881's since that's what I liked in my Krank when I had it. But what else has aggresive upper mids and a tight low-end?

Do you have any other suggestion for the preamp? And the poweramp?

Thanks!

 

[Rex Rocker]

Anyone?

 

[BatmansRigTalk]

I pulled all the tubes out of mine and replaced the pre-amp tubes with TAD JJs.

I had groove tubes in 5150III 50W 6L6 for some reason. Out they came.

For the power tubes, I used JJ 6L6GC matched pair.

Biasing this amp is very important. I think it makes the difference between having that Gojira sound instead of a honk that causes some people to think the amp is horrible.

My EVH 5150III 50W became a much better amp after I did all that.

 

[mixn4him]

^ This BIAS has to be adjusted. have told this story several times, mine was glued wide open from the factory! Literally had to chip away the glue to adjust the bias pot. I used the Sovtek 5881's and biased it properly and the amp just crushed. No more weird fizz on the note trails just solid clear tone. Eventually sold it since it was the original non-concentric pot version and the Ch1,2 balancing act sucked...

 

[Rex Rocker]

What do you guys bias yours to?

 

[BatmansRigTalk]

I stuck with the one in the schematics. http://support.evhgear.com/schematics/EVH_50W.pdf

OUTPUT TEST AT RATED LINE VOLTAGE IMPEDANCE SWITCH AT 16 OHMS BIAS SET TO 60MV AT TP45 PRESENCE FULL CCW RESONANCE FULL CCW 150 MV, 1 KHZ INPUT AT RETURN JACK OUTPUT 5OW (28.3 VRMS) < 5% THD

So 60MV.

That is for 50W EVH.

The 100W is different if I remember so people reading this for a 100W need to go look at the 100W schematic.

Be very careful. Unplugged amps and exposed circuit boards can still have components with a residual lethal charge. To the amp tech if there are any doubts.

 

[Meeotch]

I stuck with the one in the schematics. http://support.evhgear.com/schematics/EVH_50W.pdf

OUTPUT TEST AT RATED LINE VOLTAGE IMPEDANCE SWITCH AT 16 OHMS BIAS SET TO 60MV AT TP45 PRESENCE FULL CCW RESONANCE FULL CCW 150 MV, 1 KHZ INPUT AT RETURN JACK OUTPUT 5OW (28.3 VRMS) < 5% THD

So 60MV.

That is for 50W EVH.

The 100W is different if I remember so people reading this for a 100W need to go look at the 100W schematic.

Be very careful. Unplugged amps and exposed circuit boards can still have components with a residual lethal charge. To the amp tech if there are any doubts.

I thought this thread was helpful: https://www.thegearpage.net/board/index.php?threads/recommended-bias-for-5150-iii-50-watt.1164113/

Does the schematic mean 30MV per tube?

 

[BatmansRigTalk]

I have no idea where they are getting that from. They seem to be using some sort of formula. I didn't do that.

What I did is exactly what you see here.



60 MV.

I have been playing my EVH since and even a few minutes ago. No problems. Sounds great.

Look at schematic page #2. Look at what it says on the right in the box. You set the bias of both power tubes at the same time. It's one dial.

Just follow that YouTube.

 

[Markmetalguitar]

I tried both the black and red base TAD 6L6GC. I love both and after PROPERLY BIASED it became a monster. EVH amps in general are biased “cold”. Mine was somewhere at 48mv. 60 is recommended and I had mine set slightly hotter at 62mv. with the TAD 6L6GC RED BASE. Low end a little darker than black base but both are killer! Made in Germany and not too pricey at around $75/matched pair. (See pics) Also try EH7025 in pre V1 V2 V3 and V4. It’s a huge improvement over stock tubes.