Any thoughts on how to "soften" attack on a Fender Bassman ?

[mort]

What speakers are you using?

[Chevy]

What speakers are you using?

Have 4x10 Jensen P10R's, Celestion G12-65, plus some old beater Carvin British sound 12's.

[Silvertone Jockey]

Ahhh.... now there's a good one... thanks, for the tube tips... didn't think about the tube compression part... will try get hold of a couple of those tubes. Any other suggestions for tube types will be appreciated... don't have to be 12AX7's; 12AY7, 5751, maybe even 12AT7 would work fine I guess, especially if they compress the top end. Good idea !

I really love a 12BZ7 in V1 and sometimes I throw one in the PI slot instead of a 12At7 on some amps. The BZ7 is taller and draws more filiment current and has the most gain of all possible 12AX7 subs. I've never had an issue with any negative transformer or other component problems using this tube. Try it you might just like it

[Chuck H]

I really love a 12BZ7 in V1 and sometimes I throw one in the PI slot instead of a 12At7 on some amps. The BZ7 is taller and draws more filiment current and has the most gain of all possible 12AX7 subs. I've never had an issue with any negative transformer or other component problems using this tube. Try it you might just like it

The 12BZ7 has the same gain as the 12AX7. So, more than other 12**7 types but NOT more than 12AX7. I've never been able to take advantage of their gain because they tend to be microphonic. I expect this is a result of the longer plate and slighter construction combined with their higher gain. So I can't comment on any perceived compression characteristics with clipping. IMHE it's tough (or impossible) to find non microphonic examples and it's not a good guitar amp tube. Especially for combo type amps.

[Silvertone Jockey]

The 12BZ7 has the same gain as the 12AX7. So, more than other 12**7 types but NOT more than 12AX7. I've never been able to take advantage of their gain because they tend to be microphonic. I expect this is a result of the longer plate and slighter construction combined with their higher gain. So I can't comment on any perceived compression characteristics with clipping. IMHE it's tough (or impossible) to find non microphonic examples and it's not a good guitar amp tube. Especially for combo type amps.

The data sheet may say gain is the same on both tubes but plugging one in at V1 will result in the amp breaking up at a lower volume than normal. Also the tone is beefier with more timbre to my ears. All I can say is the 12BZ7 is my favorite preamp tube in my combo guitar amps, and I have had none of the microphonic problems thus far. The tubes I'm using are NOS 1950's Tung Sol and Westinghouse black plates.

One drawback is they do raise the noise floor very slightly, but I haven't found it to be annoying in any way. As always YMMV and probably will

[J M Fahey]

Maybe you don´t have an electronic problem but you simply don´t like that amp ... same as you didn´t like the Super reverb

Besides that, you mention 3 kinds of speakers but not any difference of sound depending on which one you use, which I find strange.
Those Jenses are jangly and can be ice picky ; the Celestion is middier although still has highs, just a tad lower frequency and the Carvins are duller , relative to the other two.

[Pedro Vecino]

Amp has diode rectifiers. New JJ 6L6GC output tubes. Biased at around 35 mA. B+ around 470V. Decent old stock preamp tubes.

With rectifier diodes and 470V, complicated. In the reissues with GZ34 and 450V the first thing I do is putting one 5U4 to reduce it to 420/425V. That's the starting point for me.
Other details (smaller but effective) are using polyester film foil capacitors instead of plain metallized polypropylene (if applicable), a good 12AY7 or 5751GE in the first socket and in the case of alnico Jensen 10 " speakers, make an initial break to soften if they are new.

[Tone Meister]

The 12BZ7 has the same gain as the 12AX7. So, more than other 12**7 types but NOT more than 12AX7. I've never been able to take advantage of their gain because they tend to be microphonic. I expect this is a result of the longer plate and slighter construction combined with their higher gain. So I can't comment on any perceived compression characteristics with clipping. IMHE it's tough (or impossible) to find non microphonic examples and it's not a good guitar amp tube. Especially for combo type amps.

I've found that the 12BZ7 is an excellent replacement for a 12AT7 in the phase inverter when one wants to drive the power tubes harder. Microphonics would not be an issue. I was going to suggest the OP try one in the PI of his Bassman if lowering the preamp voltage didn't have the desired effect.

[stormbringer]

Makes sense, but won't all audio frequencies would be compressed the same amount ? It's just the top end I'm concerned with. Also, you'd have to drive the preamp stage close to the power rail limits to take advantage of power supply compression... not something that would be available at any volume setting.

As far as I understand, it would affect the sharp peaks (e.g., leading attack) first and thus affect higher frequencies before lower frequencies. If bass gets mushy, you could always tighten that with a smaller coupling cap or bypass cap.

[Silvertone Jockey]

Hook up some peavey scorpion speakers that'l soften the attack

[stevehoover]

Are you using the stock values in the power supply filter caps?
I have seen "bumped up" power supply's exhibit a kind of brashness to the top end as well as a more solid bottom.
One of those more is not better situations.....

[J M Fahey]

Guitar... yeah, I guess that's an option. But I have run across other vintage Fender guitar amps with the same issue... like a Pro Reverb for example. Never found out what the deal was with that amp, either.

Ok, clear enough now.

You simply don't like Fender sound, period.

No tweaking will change that, even less replacing tubes or changing bias.

Try other amps you might like better.

[stokes]

Had a harp player using a '59 Bassman re-issue with a bullet mic.He wanted to take some top end off it,using it with the treble on zero didnt let him turn the volume past 2 1/2 without screaming feedback.I know its a different situation,but it might be similar enough to work for you.I replaced the SS rect with a 5R4 tube.Also a 12AY7 in V1 and a 12AT7 in the PI.I also put an adjustable bias pot and lowered the current draw to 25ma's,plate voltage was about 405v's.We were able to get the volume to 5-6 before feedback with the treble at 5.I'm thinking in your case the AY7 in V1 and the AT7 in the PI might be enough to get you what you want.The rectifier switch in your amp will require adding a tube socket and likely a 5v transformer,may be more than you want to tackle.