EVH 5150 iii EL34 50w volume keeps changing slowly while playing.

[sdn25]

Did you eliminate the possibility that the EL34 in the amp were knackered, eg try your spare, known good fresh set of EL34 in it, to ensure that the comparison to your 6CA7 was a fair one?

Yep! Ordered a set of both EL34s and 6CA7s to test the amp with.

 

[paradox419]

Also if anyone reads this and if you own an el34 5150, I highly recommend putting in 6CA7s. They make the amp sound much better imho. Tighter low end, clearer mid range, less muddy at higher volumes, and much more!

I agree completely. I have the 1x12 EL34 combo from 2019. It gets played through the combo speaker and the EVH 412 at the same time. JJ EL34Ls sound awesome in it... JJ 6CA7s sound even awesome.r. Clearer with tighter thump, without losing the el34 grind \m/

 

[Pete Farrington]

Ordered a set of both EL34s and 6CA7s to test the amp with.

Thanks!
Just for the record, which brands?

 

[sdn25]

Thanks!
Just for the record, which brands?

They’re JJ tubes

 

[sdn25]

Update: got the new amp in and……guess what, the damn problem is back. This to me says it’s a problem with my outlets. I highly doubt two different amps show the same issue.

A note on my outlets: I measured them and they’re putting out 124V. That can’t be good for the amp. Could that be causing this issue?

Also, is there any chance that my suhr reactive load might be causing this?

 

[Pete Farrington]

A note on my outlets: I measured them and they’re putting out 124V. That can’t be good for the amp. Could that be causing this issue?

Closer to 120V is preferable but 124 is only 3.3% higher, it really shouldn’t cause a problem.

is there any chance that my suhr reactive load might be causing this?

It doesn’t seem an obvious suspect but nonetheless, it should be ruled out by checking for the issue without it in the signal chain.

 

[XTRXTR]

Update: got the new amp in and……guess what, the damn problem is back. This to me says it’s a problem with my outlets. I highly doubt two different amps show the same issue.

A note on my outlets: I measured them and they’re putting out 124V. That can’t be good for the amp. Could that be causing this issue?

Also, is there any chance that my suhr reactive load might be causing this?

With any problem of an amp the troubleshooting process should always be in a process of elimination. What is it not? Cables, power cord, effects connected, speakers, load boxes, wall AC voltage, internal components...it goes that way until you drill down everything it can't be and you find the thing it is. It is good practice to make a check list and notes as you go so you don't cross your on path on the trail. IOW repeating your process/path along the way, typically if that happens you need to start the process again or you will keep circling around and crossing paths over and over.

The only remedy is being meticulous and logical from the beginning to save yourself extra trouble. But all experiences are learning experiences for future projects - that is the silver lining. Eventually you build up a memory bank of things you see often and start with those. I usually go with mechanical connections first since they have a higher probability of failing than a part that just sits there. Then move on to the most likely part to the least likely part. If all that fails I scope trace a signal from input to output while chopsticking for bad connections, cold solder, broken connections.

I hope you get it sorted out soon - best of luck, sometimes that is all you need, just a bit of luck.

 

[sdn25]

With any problem of an amp the troubleshooting process should always be in a process of elimination. What is it not? Cables, power cord, effects connected, speakers, load boxes, wall AC voltage, internal components...it goes that way until you drill down everything it can't be and you find the thing it is. It is good practice to make a check list and notes as you go so you don't cross your on path on the trail. IOW repeating your process/path along the way, typically if that happens you need to start the process again or you will keep circling around and crossing paths over and over.

The only remedy is being meticulous and logical from the beginning to save yourself extra trouble. But all experiences are learning experiences for future projects - that is the silver lining. Eventually you build up a memory bank of things you see often and start with those. I usually go with mechanical connections first since they have a higher probability of failing than a part that just sits there. Then move on to the most likely part to the least likely part. If all that fails I scope trace a signal from input to output while chopsticking for bad connections, cold solder, broken connections.

I hope you get it sorted out soon - best of luck, sometimes that is all you need, just a bit of luck.

It’s most definitely the outlets. Tested the amp on a completely different circuit and it works perfectly on the same setup. Connect it back to my other outlet and boom, everything falls apart. Ig this outlet isn’t rated for high power draw (it’s a dorm room).

I connected the amp to a socket where most people would attach mini fridges. I assumed a socket that is used for powering a fridge should be able to handle an amp and I guess it did. Weird stuff tho. Would’ve driven me mad if I kept the old amp. Hey, at least I saved some money by getting this one.

 

[Ken Underwood]

Lesson to be learnt, never look too deep as it is often staring you in the face, plus never attempt something that you do not fully understand, leave it to those who do.

 

[JDynamite]

Same exact craziness happened to me with my Orange Dual Dark amp. Tried everything you did, over and over again. Countless tubes. Unplugging re-plugging here and there. It would seem to have resolved itself and then it would come back. What I didn't do was go directly to the amp without disconnecting from my pedal board.

Have you tried going straight in?
amp ‹-- guitar
sorry I missed it if you did
Turns out one of my custom built pedals had a bad output jack.

 

[nasticanasta]

My old 84 50w Marshall did the same thing until I put in new power tubes

 

[nasticanasta]

That’s not biting a bullet, but rather fundamental cost. You’ve got a valve amp, so you need spare, known good valves for it.
One way or another, they’ll all fail eventually. A spare is needed, on hand, because it’s sure to happen at an inconvenient time.

I carry 2 sets of spare power tubes in my gig case..like you said, it's bound to happen when you're playin'

 

[sdn25]

Lesson to be learnt, never look too deep as it is often staring you in the face, plus never attempt something that you do not fully understand, leave it to those who do.

To be fair, from my specific symptoms, the last thing you expect to have caused this problem is a bad socket. It’s one of those cases where if it didn’t happen, no one would’ve known it’s a possibility — unless of course it’s obvious.

 

[Ken Underwood]

It would be my first port of call, never rule out the obvious

 

[anitoli]

My question is, is it a faulty recepticle or an issue with the voltage on the line? US code specifies 15A minimum line current. No one guitar amp is gonna overload or brownout a 15A line. Is there another load connected to this line?

 

[sdn25]

My question is, is it a faulty recepticle or an issue with the voltage on the line? US code specifies 15A minimum line current. No one guitar amp is gonna overload or brownout a 15A line. Is there another load connected to this line?

Seems like it’s an issue with the voltage on the line. The only other loads connected to the other socket is a laptop charger and a pedalboard power supply.

 

[XTRXTR]

My question is, is it a faulty recepticle or an issue with the voltage on the line? US code specifies 15A minimum line current. No one guitar amp is gonna overload or brownout a 15A line. Is there another load connected to this line?

Now we know it was a wall outlet. It seems the amp was acting like it was on a light bulb limiter maybe some ballast. Perhaps in the circuit run back to the breaker there were somethings wired in series for who knows what reason. I've seen a lot of miswired outlets, motors on the same circuit that should have an independent run. Popcorn machines, electric pizza ovens. Whatever it is it isn't proper. Someday we will hear about a dorm building "burning down the house"