Question about 6V6 Bassman build.

[bigguy12321]

I am thinking about a future build idea and was wondering if any of ya'll might have some input. I am thinking about building a 6v6 powered Bassman style amp. In other words, same architecture but lowered voltage for 6V6.

Has this been done before? Probably, but I can't find it. Any opinions about how it might sound? I like the idea of the Bassman but I don't EVER need 50 watts. Is there anything else close?

All thoughts, ideas, suggestions are welcome.

Thanks!

a

 

[Phrygian77]

I am thinking about a future build idea and was wondering if any of ya'll might have some input. I am thinking about building a 6v6 powered Bassman style amp. In other words, same architecture but lowered voltage for 6V6.

Has this been done before? Probably, but I can't find it. Any opinions about how it might sound? I like the idea of the Bassman but I don't EVER need 50 watts. Is there anything else close?

All thoughts, ideas, suggestions are welcome.

Thanks!

a

Which Bassman? You could probably use the Classictone PT with the 610V secondary, in a bassman chassis. SS rectified with a pair of JJ 6V6s tubes, for blackface, or with a GZ34 for tweed.

 

[bblumentritt]

Check out Doug Hoffman's Plexi 6V6 amp.

https://el34world.com/schematics.htm#Hoffman_Plexi_6V6_

 

[bigguy12321]

Check out Doug Hoffman's Plexi 6V6 amp.

https://el34world.com/schematics.htm#Hoffman_Plexi_6V6_

DING DING DING!!! We have a winner!!! Thank you @bblumentritt . That is what I was looking for. And it even has a master volume. I'll look at it closer later for specifics, but as always... " This site rocks"

With a few tweeks from @robrob , I'll make it my own.

a

 

[Phrygian77]

DING DING DING!!! We have a winner!!! Thank you @bblumentritt . That is what I was looking for. And it even has a master volume. I'll look at it closer later for specifics, but as always... " This site rocks"

With a few tweeks from @robrob , I'll make it my own.

a

I'm assuming you don't care if it's not in a Bassman chassis then. Doug's build uses an 18 watt PT and OT. That layout is also designed for his Stout chassis which has the tube sockets up front. I wouldn't try to use his board in any other chassis.

The PT I was talking about fits in any Bassman chassis, and you could use the original layout.

 

[Alamo]

The Yellow Jackets tube converters might tick all your boxes.
https://www.yellowjacketstc.com/
keep the sound of the tradional build but lower the output. a lot.
and...you can get the original sound back by just changing the tubes.

 

[schmee]

You mean BF or tweed?
In BF I guess it's pretty much a non verb Deluxe
In Tweed maybe a 5F11 Vibrolux?
I dont think in the end you will be breaking any new ground...

 

[Phrygian77]

You mean BF or tweed?
In BF I guess it's pretty much a non verb Deluxe
In Tweed maybe a 5F11 Vibrolux?
I dont think in the end you will be breaking any new ground...

I wouldn't quite call it a non-reverb Deluxe. The blackface Bassman is SS rectified, the preamp voltages are higher, there's no tremolo circuit dragging down the output of a gain stage, and there are no coupling caps preceding the mix going into the PI. Not to mention the Bassman has a switched 120pF bright cap, and deluxe has a fixed, but subtle, 47pF bright cap.

A 5F6A Bassman is nothing at all like a 5F11 Vibrolux. The 5F6A and 5F8A are based on the Western Electric circuit, and they're completely unique out of all the vintage Fender amps. The have a TMB tone stack feed by a cathode follower, and an LTP PI. The 5F11 has a simple tone control (more midrange) and a cathodyne PI. The 5F11 has more in common with the 6G2 Princeton.

 

[Wyatt]

Sara Ritcher built 6V6 versions if the 5F6a.

The only real trick would be to get the power tube plate voltage down while maintaining the PI and preamp plate voltages.

 

[bigguy12321]

Ya. I just got a better look and the 6V6 Plexi isn't exactly what I was looking for. Close though. It shows me that it's possible but I guess i was picturing a lower volume Tweed 5F6-A so that is where it'll probably end up. There is no one perfect amp but there may be a perfect one for me. I've got the power trans already. It's 305-0-305 110ma. I'm looking at using solid state with switchable tube rectifier. Also switchable fixed and cathode bias. Switchable pre-gain stages for different flavors of distortion. I'm going to try to build one amp for me for all my uses. Mostly playing around the house but some recording and light gigs. I'm wanting a head unit with a small speaker ala RobRob's Bassman mod page. Plus if I go with the Bassman topology I get the benefit of a bunch of modification ideas to try.

I wasn't thinking I just uncovered the ultimate amp but was wondering if there might be sound clips of something similar. After some more careful searching I found several more close ideas to chose from. The 5E4-a Super-Amp is close, as is the Blackface Deluxe no reverb or trem. Also the Brown Deluxe no trem would get me close. As usual I have to "Better go on home, son, and make up your mind."

Thanks for all who played. I am still open to ideas or suggestions.

Just FYI I am not really concerned with copying any one amp exactly. I'm more interested in flexibility. Kind of like if we all stuck with tradition we'd still be knocking our women over the head and dragging them back into the cave. And I don't think I'd like living in a cave...

...that was a joke...

a

 

[Wyatt]

Why not just build a stock 5F6a, use JJ 6V6S and a Deluxe Reverb OT? The JJ's will handle the 430V on the plate. You can still use a less efficient rectifier (like a 5R4) and fixed-/cathode-bias switching.

The issue with swiss-army amps is usually we find one preference and never change it again.

 

[Wally]

Take a look at the Fender Pro Sonic schematic. It does all of the things you say you want. In fact, just buy a Pro Sonic combo and a good attenuator...forget about the 6V6’s.

 

[Uncle Daddy]

What about the 6V6 5e4-a Super? About 20 watts, I'm guessing. I'd love to try one of these alongside my 6L6 version.

 

[Uncle Daddy]

What about the 6V6 5e4-a Super? About 20 watts, I'm guessing. I'd love to try one of these alongside my 6L6 version.

View attachment 543626

Edit- I just read your post mentioning this version. Mine is a 6L6 version, biased for 5881s. I love it; it makes a Deluxe sound like a boxy toy. Possibly a bit overkill for home use, but it sounds glorious!

 

[Snfoilhat]

After some more careful searching I found several more close ideas to chose from. The 5E4-a Super-Amp is close, as is the Blackface Deluxe no reverb or trem. Also the Brown Deluxe no trem would get me close.

Between the 5F6-a and variants, the 6G3, the AB763 non-reverb amps, to say nothing of designs that are topologically similar but with different brands/pedigrees and power tubes (Vox, Dr. Z, Matchless), you seem to have seen that you can do whatever you want. An input stage, a cathode follower, a tone stack, a long-tailed pair phase inverter, a pair of 6V6GTAs. It will all fit together fine.

The rest of your work is going to be more concerned with figuring out what you actually want, and how to describe it. Some folks will hear '5F6-a' and think anything vaguely plexi-like will fit. Some folks will say if the B+3 and B+4 voltage supplies aren't within ±20% of the Bassman schematic, your amp isn't really anything like a Bassman. Or if it doesn't run 5881 tubes in the first place. I say this without judgment; it's a communication thing, and concerned with a difficult subject matter.

Lots of different factors contribute to what an amp sounds like, and they can't all be dissected and rearranged in perfectly clear predictable ways.

My favorite little snippet of online culture I picked up from EL34 world is this: someone inevitably posts something like 'hey, I want to build an XYZ with ABC and 123, what will it sound like?'

And the comeback I saw one of the mods use was: 'Build it and tell us.'

I built this this summer. It's rad. My most Bassman-like amp so far. (It's not a flexible as you say you want, but I share it to give an example of how the known circuit blocks can be arranged and tweaked to good effect by an amateur). Good luck!

 

[Silverface]

I like the idea of the Bassman but I don't EVER need 50 watts. Is there anything else close?

You may have a wrong interpretation of the meaning of power.

Not needing "50 watts" doesn't really mean anything. Power is a poor indicator of loudness (as Sound Pressure Level), if that's your concern. It's not difficult to build a 50 watt amp and 20 watt amp that's louder. To cut the loudness in half takes a 4x to 10x reduction in output power, all else being equal.

Switching power tubes to 6V6's - even if everything else is equal - will only result in a slight reduction of loudness and headroom (I prefer that term to "volume" as volume can be confused with the control on the amp and ho it operates). Speaker sensitivity and total cone square inches, cabinet type and construction and overall amp design mean far more in regards to loudness that output power.

There are some pieces of information missing in order to make qualified recommendations -

What style of music do you play; do you only play at home, jam with friends or play gigs (and if the latter in what types of places - small clubs, halls, churches, places with or without stages, ceiling heights and type, are the amps mic'd) and in any band/jam situation how many other players and - if possible - what are they using? Do you play clean, and f you use distortion do you prefer a smooth transition into output stage saturation or an instantaneous pedal-type change?

Seriously, all this stuff makes a difference - in my case I've played a variety of styles and places, so I have several gig amps. I use whichever one can be run close to the limit of its headroom with guitar controls rolled back a bit. Then I have some guitar control over the level for solos and a bit more to push the amp into mild saturation. Most gigging players I know use a similar "array" or gear. That way they have the best chance of optimizing their tone in just about any situation.

Hope that helps - if nothing else it'll give you some things to think about and possible future goals.

 

[Mike Simpson]

I have been planning to build the same basic amp.
The Richter RS22 (no longer made) was a bassman with 6v6 output (and some other changes no doubt). As far as I can tell Sara stopped building amps and the website is gone.

Here are some internet pics of the Richter RS22

 

[Mike Simpson]

 

[King Fan]

Here are some internet pics of the Richter RS22

Your RS22 idea continues to fascinate me, Mike, and those pics could probably recreate the layout.

So what do we think the cap values are on all those ODs and the several Spragues we can't read?

What else do we need to know to draw the RS22?

 

[Wyatt]

Your RS22 idea continues to fascinate me, Mike, and those pics could probably recreate the layout.

So what do we think the cap values are on all those ODs and the several Spragues we can't read?

What else do we need to know to draw the RS22?

I see no reason for any deviation from the 5F6a schematic as far as the caps, resistors, and layout are concerned. Preamp, tone stack, PI could remain unchanged.

All the changes would be in the power supply and output...

• PT swap for lower power tube plate voltage
  
• Dropping resistor changed to offset the lower B+ voltage to maintain the correct PI and preamp plate voltages
• 25-watt OT with a 6.6K-8K primary and the desired secondary
• Change the NFB loop values to compensate for new OT secondary

That's all it would take. DR iron may be ideal.