Bass amp Preamp Question

[FrankJohnson]

I have a Peavey T-Max - which is a great bass head. It generates great power, has been reliable and after some repairs due to neglect prior to my buying it, has been great.

I have tried 2-3 different 12ax7 preamp tubes in it.

The thing has two channels, and the Tube pre is on one, solid state on the other. Both are SS poweramped.

I would like to have warmer sound from the tube side, and don't get me wrong - it sounds, good - but what might be a good tube to enhance that warmth? I actually tried a Gold Pin long plate thinking the extra clean head room would be nice. it was ok, bot not what I am after.

Do I want a hotter tube, or maybe a darker one?
Not sure. Hot with dark warmth, like glowing plate warmth......that would be cool I think. I can EQ the rest in I think, if I can get the front end drive.

Ideas?

Thanks -

[stevem]

This may sound like Bill Clinton, But it depends what your definition of warmth is, do you mean more mids in a tight frequency range and a little less highs?as this is what I always find hard to get out of my solid state bass heads.
You could try a NOS RFT brand as these are known to have less highs for guitar, weather that extends enough into the bass guitar frequency range I can not say.
Your other option is to just taylor the circuit a bit to your liking as we are talking less than 5 dollars in parts that could make you love the head all the way.
I do have a 1968 Ampeg B15n, this head uses the old type octal preamp tubes and is the most loved example of what warmth is in a bass amp! Just go anf listen to all the soul and motown, and most of the top pop recordings from the 60s and the B15 is the amp you hear.
It would not be too big of a mod to change over to a octal style preamp tube, atleast for the first two gain stages if you have the room.

[Gravity Jim]

Just go and listen to all the soul and motown, and most of the top pop recordings from the 60s and the B15 is the amp you hear....

Through a 60's mic, a 60's tube preamp, a hand-assembled 60's mixing console, mastered to lacquer on a lathe, that is.

Have you tried a 12AT7?

[JAM]

Try a 5751

[FrankJohnson]

Have not tried a AT7 or 5751 yet/back at you -

i can read bout them, but what are they going to push from a sond perspective?

[JAM]

I feel the 5751 is a bit darker sounding than a 12AX7, and they have less gain.

[stevem]

Yes, I agree Jim, it was kinda the whole process.But my B15 thru its original CTS driver is the ticket.I have had a Altec 421 and a JBL d140 in it and they gave more punch(and the Altec a bunch more highs), but that relitively cheap CTS driver does it for me in terms of warmth.
Frank you might also want to play with raising the value of that last power supply resistor that feeds that first tube.
If you have around 225 to 250 volts or more at the input to the plate resistors on that first tube, going down to 185 to 190 will warm things up, and may be add a little bit of grit to the mix.
Just step up to a 1 watt larger resistor when you do this to be safe from burn out.

[stevem]

Oh! You wil also have a bit less gain from dropping the plate voltage.
Not that it will help with warmth, but have you ever tryed a compressor pedal in front of your bass? You might like it!

[FrankJohnson]

I appreciate the help guy -

I am not going to mod this amp. It sounds good as is - I just want to make it suit me a little more.

i will probably try the tubes mentioned, as I can.

I am runnign it through a SVT 410-hlf and/or a Avatar 1-12. it really sounds fine. Like I said, I want to Me-a-fy it. Mods and me have always ended up having issues.

I use a BBE with it and it helps shape the sound. Thats about as much effect as i am looking for. All of my basses are deep and either mellow or punchy, depending on teh adjustments. I just want a little PLate type character/shimmer glow, whatever is the right term.