tube amp is trebly, clipped sounding

I got my tube amp repaired, I bought some cheap EH tubes to put in it. It sounds too trebly for me, even with treble turned all the way down. It wasn't like this before. Even sounds like a harsher clipping of sorts, not smooth.
 
Is it a bias issue? Or should I go back to more expensive tubes? I had Mesa tubes in it before, I've also used groove tubes in the past which sounded great.
 
 
 
 

Am I reading correctly that you got your amp repaired and THEN put new tubes in it?

And NOW it sounds like crap?

I'm confused.  Did it sound like crap when you got it back from the Amp tech?

If it did sound bad....you'd take it back to the amp tech...right?

If it didn't....I don't understand why tubes were changed out.

Put your old tubes back in...does it sound better?  Should be that simple, really.

I replaced tubes before I took it in, but I never heard it with the new tubes because it wasn't working. It was an intermittent component, and relay for the channel switching that was bad.

So now I have it repaired, with the tubes I put in, I'm pretty sure the tech checked bias.

I haven't put the original tubes in, not sure if they both work. But yes, I know I should put those in to see if I get the sound back.

It's a Bedrock lead 50 head. I replaced the 2 el34's.

The amp is working fine, has plenty, plenty of gain. And sounds like a tube amp should to some extent, just not as pleasing to my ear as before. Especially with my les paul, which it never was too trebly before with.

"I'm pretty sure the tech checked bias."

Checking the bias is a totally legit task... but a check just sort of confirms that the amp will not melt down as the plates get hot.

After the check one must decide if the observed results seem consistent with the previous set of tubes.

At that point one may choose to adjust the bias which is usually not as easy as the check because very few amps have a true bias adjustment. Most amps require that fresh resistors be installed to truly adjust the bias. (many amps have bias balance adjustments... that is not the same thing). The fact that actually adjusting the bias is inconvenient has lead several tube vendors to label their tubes with a graded system that sort of let's you predict how it will bias in your amp.

So instead of adjusting bias on the amp a tech might simply try several different sets of tubes so as to match to the set of tubes you had previously enjoyed.

This has nothing to do with matching tube sets. Matching tube sets is simply making sure there is consistency in the set. I think matching is very important. I have read compelling arguments refuting the idea. I think it is important.

Usually the preamp tubes make more difference in tone... but once again f you really drove your amp like a sports car... I can easily imagine a fresh set of EH EL34s could do just what you are hearing.

I use a lot of 6v6 amps. EH doesn't make a 6v6 tube that's worth listening too... the EL34 may be just as nice.

Good luck,
mike

put some different tubes in it.

if THAT changes anything, then you're on the right path.

if it doesn't, take it back to the tech, he didn't do his job right.

So I forgot another detail. When the amp wasn't working, I also put in new pre-amp tubes, 12ax7's. If I remember they where MESA brand.

So if preamp tubes affect tone more than power tubes, maybe it's the preamp tubes I put in that are the cause of my discomfort.

I shall swap back tonight and see what happens.
Also, I've seen good reviews on the tungsol brand tubes. But they are three times the cost of EH.

Poor Dog
 
Sounds like something that happened to me many years ago. I took my favorite amp to a VERY famous tech for a tune up, just a tune up 'cause he was famous see... My amp came back un-usable!
 
He changed the output tubes and rebiased. What you need to learn to do is to bias your own amp - this way you can get it sounding like you want it without taking it to a tech.
 
Mike

When it wasn't working the tech replaced an intermittent resistor. Very strange. I'm actually a technician for a living, but I've never worked on amps, and I just didn't have the time to troubleshoot this. I did work on the amp for a little time. Hence the changed tubes.  I've seen a lot of strange stuff on the boards I've worked on, so I would believe an intermittent resistor.

I took it to a great technician, who's worked on amps for decades. I was suprised at how long it took him. It was because of this "intermittent resistor".

Whatever the case it was very inexpensive.

Anyway, I put the old pre-amp tubes back in. And there is definitely an improvement!
So I think my next step is exchanging the EH el34's for something else, and see how I like. But right now, the amp is jammable for my ears.