Less squish from 6V6 amp

[toneseeker74]

Do 6V6's inherently squish on the attack then bloom? I have a Gibson GA-8 Discoverer with parallel singled-ended 6V6 power tubes. It gets pretty well up into fuzz levels of overdrive, but I don't like the compressed squishiness. I'm going to replace all the filter caps with 20uF instead of a mix of 10uF and 20uF caps. Anything else you recommend, or is this just the nature of the beast?

I'd also like to change the overdrive characteristic from fat fuzz to a more crispy crunch. Again, is this possible with 6V6's?

 

[trevorus]

This is more endemic of a single ended power section. If you're wanting a more solid amp with less compression, you need more wattage and a push-pull power section for the headroom. You're running a low watt amp to it's limits, which is it's own sound. If you want tight, you need an amplifier designed for it.

 

[jon the art guy]

Re: Less squish from 6V6 amp

is there a tube rectifier in it?
I looked it up and you're running a 5y3gt rectifier tube, which is the saggiest rectifier you can find. You may want to find a 5u4gb somewhere and try it out, or switch to a solid state rectifier from Webervst.

As far as changing the overdrive characteristic, how about swapping the 12ax7 to a 12at7 or a 5751? Lower output on the preamp side should calm that angry fuzz down a bit.

 

[zzmoore]

Re: Less squish from 6V6 amp

This is more endemic of a single ended power section. If you're wanting a more solid amp with less compression, you need more wattage and a push-pull power section for the headroom.

Man...this is definitely a BIG factor.
Single ended...Cat biased...Tube diodes...compression. That is kind of what people love about this type of amp.
I am not saying that YOU do not. But for other needs, as mentioned by trevorus above, you need to also have a fixed bias, Class AB amp.
If the PS Caps are tired, that surely will make for a very different amp.
Good idea to give that a try.
best

 

[toneseeker74]

Re: Less squish from 6V6 amp

I have a 1970 Traynor YBA-1 that gives me the big solid clean sound. I push a 4x12 with Celestion G12-65's so it gets loud but not insane. Interestingly, the Traynor breaks up less than the Gibson. I figured they would be about the same, but the Gibby goes a few notches higher.

Maybe I should look into a push pull combo in the 20 watt range?

 

[trevorus]

Re: Less squish from 6V6 amp

Egnater would be a good one to look at, also check out Blackstar.

 

[jon the art guy]

Re: Less squish from 6V6 amp

I have a 1970 Traynor YBA-1 that gives me the big solid clean sound. I push a 4x12 with Celestion G12-65's so it gets loud but not insane. Interestingly, the Traynor breaks up less than the Gibson. I figured they would be about the same, but the Gibby goes a few notches higher.

Maybe I should look into a push pull combo in the 20 watt range?

The Traynor has a solid state rectifier and may be running 7027a power tubes. Those are very clean and powerful tubes. Even if it's running el34s, the low-power preamp and the solid state rectifier is going to keep it a little south of that explosive diarrhea-sounding gain that the old tube rectified/6v6 or el84 powered amps with no negative feedback loop.

 

[Gearjoneser]

Re: Less squish from 6V6 amp

My fat squishy 6V6 amp is a Fender Excelsior Pro w/15" speaker. Lately, I've been putting Bogner pedals in front of it that have a ton of tone shaping switches. It's like the best of both worlds now.

It doesn't have to be a Bogner pedal, but any OD pedal will allow you to control the tightness.

 

[jeremy]

Re: Less squish from 6V6 amp

is there a tube rectifier in it?
I looked it up and you're running a 5y3gt rectifier tube, which is the saggiest rectifier you can find. You may want to find a 5u4gb somewhere and try it out, or switch to a solid state rectifier from Webervst.

that may push the voltage too high for a typical 6v6 so check for red plating. a 5v4 recto is a good swap though. i do that in my 5e3 from time to time and it gives more headroom, volume and tightness. if you use jj 6v6 tubes you can run almost any recto tube you want since they handle more voltage, a gz34 might sound great in there. they also are a little more 6l6 like which you may like

As far as changing the overdrive characteristic, how about swapping the 12ax7 to a 12at7 or a 5751? Lower output on the preamp side should calm that angry fuzz down a bit.

this is very true as well. its easy to do and can make a big difference.

a 5751 and hotter recto tube could make this a much different amp

 

[Chickenwings]

Re: Less squish from 6V6 amp

Swap your rectifier tube for one of those solid state plug in replacements from the tube depot. That will firm up your low end and give a more immediate punch plus add a couple of watts of headroom. If thay is getting you close to what you want then the next thing would be to get a more efficient speaker.

 

[crusty philtrum]

Re: Less squish from 6V6 amp

I built an amp once with a pair of 6V6s in parallel, single-ended configuration after doing many with the same valves in the more traditional push-pull arrangement. The s/e, parallel arrangement seemed to be much more mushy than any of the push-pull layouts, despite my best efforts to increase clean headroom at the expense of output power. The best i achieved with the parallel-tube version was something that sounded like a vintage amp with octal preamp tubes.

So my opinion is that parallel s/e amps are inherently like this. But eh, don't listen to me, i've only actually done this, unlike the majority who simply speculate.

 

[Chickenwings]

Re: Less squish from 6V6 amp

Swap your rectifier tube for one of those solid state plug in replacements from the tube depot. That will firm up your low end and give a more immediate punch plus add a couple of watts of headroom. Next easy change is to employ a jj brand 6v6 because they are built to handle a much higher plate voltage than conventional 6v6s. They also have a lot more headroom which is what you are after. If that is getting you close to what you want then the next thing would be to get a more efficient speaker - possibly something like a cannabis rex which really pumps out low end and volume so you will get your maximum watts worth out of your amp (ie it will be louder amd bassiet without the amp itself having to work as hard).