5E3 too clean, no distortion

[pdf64]

That all looks good.
Well, if you can cope with the volume, then I have to agree, it's time for more gain.
The amp in the clip was almost certainly using a 12AX7 in V1.
My experience is that you'll never get a good sustaining type of overdrive from a 5E3 type amp with a 12AY7 in V1.
I try my 12AY7 out once in a while; it's fine for clean but after 10 minutes a 12AX7 goes back in and the fun starts.
Even then, an external boost is needed with a strat to get creamy sustain.
The les paul does it all on its own though.
Pete.

[fdesalvo]

A 5v4 in place of the 5y3 will help tighten up the low end. In addition, smaller coupling/bypass cap values will help remove some of the loose bass.

[paulj]

A 5v4 in place of the 5y3 will help tighten up the low end. In addition, smaller coupling/bypass cap values will help remove some of the loose bass.

Thanks, I may want to try these mods later but that would be after fixing the lack of overdrive.

[fdesalvo]

Thanks, I may want to try these mods later but that would be after fixing the lack of overdrive.

Not sure what kind of distortion you are expecting. What you should have is a nice grind from the output section. Think low gain, but thick.

[paulj]

That all looks good.
Well, if you can cope with the volume, then I have to agree, it's time for more gain.
The amp in the clip was almost certainly using a 12AX7 in V1.
My experience is that you'll never get a good sustaining type of overdrive from a 5E3 type amp with a 12AY7 in V1.
I try my 12AY7 out once in a while; it's fine for clean but after 10 minutes a 12AX7 goes back in and the fun starts.
Even then, an external boost is needed with a strat to get creamy sustain.
The les paul does it all on its own though.
Pete.

Pete,
Makes a lot of sense...I will probably switch to 12AX7. I would still like to make it crunch a little with the 12AY7. I will try to post a video of a guy trying different tubes and he has no problem getting crunch.
Funny, I have tested both kinds of guitar and keep testing with high output humbuckers. Still no crunch.

I am now focusing on the preamp voltages which seem a little low to me. I get 234V after the third cap. The V1 plates are around 160V. Isn't it too low?

[paulj]

Here is the video:

DIY 5E3 57 Tweed Deluxe 12AY7 vs 5751 vs 12AX7 - YouTube

[MWJB]

High preamp voltages translate to a cleaner sound, seems to be the opposite of what you want? 160v on the plates of a 12AX7in V1 seems perfect. A 12AX7 in a Fender preamp stage (100K plate R, 1.5K per triode cathode R) should return around 2/3 of the voltage at the B+ rail. So 2/3 of 234v is ~155v...spot on.

[MWJB]

It's pretty pointless to keep comparing to a Youtube clip of a different player through a different amp. Note that in the clip the amp is very close mic'd...what does your amp sound like with your ear 1/2" from the speaker? (No, don't do it - I'm just pointing out that things sound different depending on where you are in relation to the sound source).

The 12AY7 sections sound fairly clean.

The rectifier in the amp in the clip looks to be longer than the 6V6 tubes, looks like a Sovtek, these run much higher voltge than a NOS 5Y3 or a copper cap WY3. What are you using for a rectifier?

Your amp can just about take 385vdc at the 6V6 plates without rebiasing (late tweed Deluxes could run well in excess of this), I would aim to keep plate current ~40mA per tube max.

[paulj]

Not sure what kind of distortion you are expecting. What you should have is a nice grind from the output section. Think low gain, but thick.

Yes, that is exactly what I am expecting. Slight grind is my preference. Unfortunately, all I get is clean. Think almost acoustic guitar clean.

[paulj]

High preamp voltages translate to a cleaner sound, seems to be the opposite of what you want? 160v on the plates of a 12AX7in V1 seems perfect. A 12AX7 in a Fender preamp stage (100K plate R, 1.5K per triode cathode R) should return around 2/3 of the voltage at the B+ rail. So 2/3 of 234v is ~155v...spot on.

My other concern about this is that the the 160V that I quoted is an average.
In fact, there is 146.8 an 182.7 on pins 1 and 6 of V2. Do you think I should be concerned about this disparity?

[paulj]

It's pretty pointless to keep comparing to a Youtube clip of a different player through a different amp. Note that in the clip the amp is very close mic'd...what does your amp sound like with your ear 1/2" from the speaker? (No, don't do it - I'm just pointing out that things sound different depending on where you are in relation to the sound source).

The 12AY7 sections sound fairly clean.

The rectifier in the amp in the clip looks to be longer than the 6V6 tubes, looks like a Sovtek, these run much higher voltge than a NOS 5Y3 or a copper cap WY3. What are you using for a rectifier?

Your amp can just about take 385vdc at the 6V6 plates without rebiasing (late tweed Deluxes could run well in excess of this), I would aim to keep plate current ~40mA per tube max.

I am at 41.2mA per tube right now. I can go lower with a Zener but that didn't solve my problem. My attempt to try the higher voltage will be to verify that the preamp is maybe running too cool to overdrive the second stage. I agree that this will likely not work but I am running out of ideas. I will raise the volts for just a few minutes. It shouldn't melt the tubes right away.


I am indeed using the famous Sovtek 5Y3 rectifier.

Well, thanks to the low voltage tap on the transformer which has been in use all this time, my B+ is actually not that bad.
That is why I am surprised about the lack of crunch, even if I lower the voltage with Zeners.

Besides that test, I really don't know what to look for.

Bad cathode bypas cap? How would I test it?

Other caps seem OK, since everything is working.

I have checked the resistors on the board and all the connections measured with ohm-meter look good.
Resistor values are all pretty close within tolerances.

I guess the key question for you people who know much more than I would be:

What would possibly make the V1 have the insufficient gain to overdrive V2? Or what could be happening with V2 that it can't be overdriven by V1?

And finally, the amp is pretty loud so I believe the signal gets amplified rather well. So my previous questions make no sense....ouch!

[deci belle]

Maybe you could show a picture, Paul!

Even with NOS tubes across the board or using using a 5ar4 rectifier with 410v on the plates of those jj tubes which are not 6v6s, I still get easy breakup on my scratch-built 5y3.

V2 pins 1 and 6 are 184v and 228v on my 5e3 with the 5ar4 rectifier. With an NOS 5y3 V2's pins 1 and 6 are 159v and 200v.

I think this problem is something other than a high voltage issue.

I though Loudthud might be on the right track with the input load resistances.

So let's see a gut-shot of your build!

[paulj]

Maybe you could show a picture, Paul!

Even with NOS tubes across the board or using using a 5ar4 rectifier with 410v on the plates of those jj tubes which are not 6v6s, I still get easy breakup on my scratch-built 5y3.

V2 pins 1 and 6 are 184v and 228v on my 5e3 with the 5ar4 rectifier. With an NOS 5y3 V2's pins 1 and 6 are 159v and 200v.

I think this problem is something other than a high voltage issue.

I though Loudthud might be on the right track with the input load resistances.

So let's see a gut-shot of your build!

My bad,
Those pin 1 and 6 are supplied with different voltages. So the disparity must be there. My head was spinning when I wrote that!

Will post photos soon!

[paulj]

Gutshots!

[paulj]

One more