Blonde Bassman build suggestions...

[dehughes]

Hey David, another idea would be to talk with TV the Wired Turtle and tell him what you're wanting to build. He's a 6G6-B nut; His current amp, I believe is a real 1963 6G6-B that was slightly modified by Brian Gerhart.

I spoke to TV back in April of '07 about this same thing, and he said that with a Gretsch or a Gibson one wants the Normal Channel through a 2x12 of Vintage 30s. He said the Bass Channel is great with a solidbody, though. I'll have to e-mail him again and see if his opinion has changed.

[dehughes]

Cool. So then, the treble pot is an essential part of the 6G6-B, huh?

What value mid pot? 10k? 25k?

If trying for Brownface 6G6-B clean channel tone then the 350k/70k treble pot is needed-----i've also built Brownface Tremolux and Bandmaster circuits using this pot---- but if building the 6G6-B Bass channel this 350k/70k pot isn't needed----it just depends on what you want to build.
For the 6G6-B/Plexi head i was interested in seeing what kind of tone quality i could get out of the single preamp 12ax7 + PI (6G6-B clean channel)------ i already knew i could get impressive tone out of a 5F6-A/early Marshall-type preamp configuration, with two preamp tubes before the PI-----maybe i'll look into building the 6G6-B bass channel in a later build.
I used a 10K Mid pot.........................gldtp99

Interesting. Could you explain to me exactly what is happening with that 350k tapped treble pot on the normal channel? Is it acting like a tone pot, of sorts?

[jjman]

A faithful build would require 4 nine-pin sockets.

If it were my build I would sacrifice the normal channel and add bias tremolo. The normal channel looks pretty basic with 2 stages and is very similar to the normal channel on most BF/SF models. But the bass channel has 4 stages with mucho gusto potential.

But I am a Trem whore…….

[dehughes]

A faithful build would require 4 nine-pin sockets.

If it were my build I would sacrifice the normal channel and add bias tremolo. The normal channel looks pretty basic with 2 stages and is very similar to the normal channel on most BF/SF models. But the bass channel has 4 stages with mucho gusto potential.

But I am a Trem whore…….

Trem would be cool...and essentially out of the signal path, right? If you're a trem whore, I'm a "less is more" whore. I guess I'm looking for a one-trick pony that does what it does supremely well...

[Firestorm]

I only have 5 holes in the front panel, so my pot selection is going to be a bit, well, limited.

You can get replacement concentric pots for the Fender '62 American Vintage Jazz Bass. These are made by CTS, so can take them apart and replace the resistance tracks with any values you need. So, in effect, you can have 10 pots in your 5 chassis holes. You can get knobs for these from Warmouth (and others).

[jjman]

A faithful build would require 4 nine-pin sockets.

If it were my build I would sacrifice the normal channel and add bias tremolo. The normal channel looks pretty basic with 2 stages and is very similar to the normal channel on most BF/SF models. But the bass channel has 4 stages with mucho gusto potential.

But I am a Trem whore…….

Trem would be cool...and essentially out of the signal path, right? If you're a trem whore, I'm a "less is more" whore. I guess I'm looking for a one-trick pony that does what it does supremely well...

I used the Blonde Tremolux approach for my the trem section of my homebrew head. That type modulates the bias of the output tubes up and down, as apposed to the “roach” type that grounds out some of the preamp signal.

http://www.schematicheaven.com/fenderam ... _schem.pdf

I just replaced the oscillator triode's cathode resistor/cap with an LED that blinks on the front panel with the trem speed. Got the idea from valvewizard's site.

http://www.freewebs.com/valvewizard1/trem1.html

Works nice and also confirms that the DC power is on (not in standby mode.)

But it won’t be a “Bassman” if it has trem.

[dehughes]

Very cool idea. Eric has a good idea as well... I'll have to think these over.

I did, however, solve my front panel problem, by making some pots switches, and moving some pots to the back panel. I'm trying to think this through as much as possible beforehand, as I know I'll have to re-engineer things enough as is. Always do.

[dehughes]

One question, though: How essential to the Brown Bassman thing is that quirky, special-tapped treble pot? That is, I'd like to get my amp to cover the Brown Bassman thing, as well as touch upon some of the Blackface and possibly even Tweed Bassman (JTM-45) tonalities, but am not sure if that Treble pot is the deal-breaker.

[BTF]

I actually used the standard non-tapped 250K pot for my tone stack in my re-worked 864. At that time (the early 80's) I couldn't conveniently find a tapped 350K. I decided to use a preamp from Ken Fischer in the Bass Channel and kept the stock setup in the Normal Channel with the power amp the 6G6-B. Although it no longer resembles the AA864, I dearly love the amp.

As to the slope pot, I installed one in a custom-build rack preamp in the late 80's. There was a Treble pot, Slope, Mid and Bass. The added Slope had its pros and cons, as you could change the slope, then change each of the tone controls. It was almost too much to twiddle with! It did come in handy when lower gain settings were used with the preamp.

Whether you need the mid pot I can't actually say. As you turn the Slope up, the amp gets boxier, boomier and louder. Turned down, the mids become slightly more attenuated and the sound more "refined". Of course, this also depends on which tone stack you use. You could use the Blackface, Tweed or Brown/Blonde.

Hope this helps. Good Luck, BTF.

[6G6]

I think the 350K pot is part of the brownface sound.
I's go 25K on the midpot.
The normal channel alone will get you a brownface sound,
that is between the blackface and the tweed/Marshall sound.
I like the stacked pot idea for maximizing the limited real estate.

[dehughes]

Cool guys. Thanks so much!