Bassman one wire "hot wired" mod?

[Lefty Lou]

No response is worse than a response, and from the silent treatment I take it the replies wouldn't be at all good. Thanks for indirectly answering my question everyone. I felt it, but I didn't want to make a judgement until the fat lady sang, and right now she's a squeelin'.

[Sparky4444]

No response is worse than a response, and from the silent treatment I take it the replies wouldn't be at all good. Thanks for indirectly answering my question everyone. I felt it, but I didn't want to make a judgement until the fat lady sang, and right now she's a squeelin'.

That guy went silent...He ain't talking because he is selling his mod...he won't give it away...I guess if the mod isn't that expensive then a guy could get it done by him and then dish on what he did...

Chief sent me that book mightymike was talking about...I haven't got it yet but when I do I'll check it out and see what comes from it

[Lefty Lou]

No response is worse than a response, and from the silent treatment I take it the replies wouldn't be at all good. Thanks for indirectly answering my question everyone. I felt it, but I didn't want to make a judgement until the fat lady sang, and right now she's a squeelin'.

That guy went silent...He ain't talking because he is selling his mod...he won't give it away...I guess if the mod isn't that expensive then a guy could get it done by him and then dish on what he did...

Chief sent me that book mightymike was talking about...I haven't got it yet but when I do I'll check it out and see what comes from it

Fortunately the issue wasn't over him doing any work for me. I got a heads up from another member in the form of thread(s) that "Surreal" had posted on HC and RT, "BOY" what an eye opener.

When you get the book let me know what you think.

[Flames1950]

Was talking to MightyMike on the phone today, and he was asking me about this thread........

From what Chieffo is saying about both channels being hot -- I think you're overlooking something about the most common of the blackface Bassman heads, the AB165 -- BOTH channels got the extra 1/2 of a 12AX7 in these, there was no longer any gain advantage to trying to use the muddy Bass channel.

So if you take the unused other half of that 12AX7 to make an extra gain stage it would likely be wired up for both channels since they were already being joined together before that point in the amp. Tune it for a relatively flat response and set the voltage dividers up on the way into the stage to keep things under control and the basic sound of each channel stays the same, just hotter........barely even devalues the insides of a BF Bassman with components mounted to the tube socket carefully.

You can blackface the power amp section or not as you choose, I don't think the AB165 is too bad as is when coupled to the right speakers, not like the nasty AC568 amps that take a lot more work to get the goods out of.

I have a stock AB165 here, but I'm prolly going to sell it this spring so I ain't trying any of this, mind you........

[NY Chief]

Hey, Andy!!!

I might be interested in that Bassman and maybe even with the mod to see if that's what we've been talking about it. Shoot me a PM on it. ( Like I NEED ANOTHER amp... )

[NY Chief]

[
Chief sent me that book mightymike was talking about...I haven't got it yet but when I do I'll check it out and see what comes from it

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Mon 11/25/2013 4:33 am
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[Flames1950]

Problem is Chief.......the matching skinny tall 2x12 cab has to go with it........no one wants to deal with shipping one of those!!! Have a very early '67 AB763 silver face Bandmaster and big 2x12 in the same boat, so it's probably Craigslist for both.

[NY Chief]

OK, but IF i happen to come by that way...

[NY Chief]

OK, but IF i happen to come by that way...

[Flames1950]

Hey, if you show up this far from home with a vehicle big enough I'll deal......

[Flames1950]

Back to the mod idea though, assuming you start with the most-common AB165 amp.......the extra gain stage that both channels share is actually pretty "watered down" and can easily provide lots more gain by changing resistor values. It even has its own little feedback resistor (a 220K) and changing that alone will help bump up the burn. So you may get the desired sound without even adding the unused half of that 12AX7/7025.

[NY Chief]

hmmm, will a 2-12 fit on the tour pak....

Andy any chance of pic or diagram of that? I'm a visual guy...

[mightymike]

Changing that 220k up?

[Flames1950]

I would try 470K to start and only work up from there.....I'm pretty sure I tried just removing it on a different Bass man and the noise floor got pretty obnoxious with no local feedback at all in that stage.

[mightymike]

I downloaded a layout, but it's blury.. Damn it. I want to find that 220k, and the unused half of the tube so I can see what your saying, and the figure out how exactly to hot wire that extra half of the tube.

I have a schematic of the Bandmaster from earlier in the thread.

http://satamax.free.fr/bandmastermod.jpg" onclick="window.open(this.href);return false;

On the normal channel there's a 100k plate, then a .047uf ( coupler I'm assuming) then a 220k. Is that it? Is that tube v1? Or is it the one on the vibrato channel where the red wire is drawn to another 220k v1? That's where a clear layout would help.

Also, wouldn't upping the a side of either of those 100k plate resister to 220k or 330k increase gain as well? Kind of like doing a Jose. Figured I'd throw that in since we're talking one wire mods and all.