Normal Channel Only BF Super Reverb Build?

[JoeTele]

Hi,

I've got a successful Tweed Princeton build under my belt and am looking to add 6L6 Blackface to my stable. Thing is, I love the simplicity of both Tweed circuits and many Dr. Z's, and prefer that effects come from pedals. I thus would like to build an amp consisting of only the normal channel of a BF Super Reverb, though I would like to replace the stock tone stack with a Vibrato Channel's to get treble, middle, and bass controls, as well as use a single 12-inch speaker (which I understand would require a non-stock OT for correct impedance). I've studied the layout of the Super closely and am just wondering if removing the parts that work only with the vibrato channel can be done without significant re-engineering to get the normal channel to work on it's own. My hope is that this would be a 5-tube amp when I was done (1 preamp, PI, Rectifier, 6L6's). Also, would the right OT for the 12" speaker be an easy substitution?

I've some questions about a few details and possible (but non-essential) mods but want to make sure that the basic mission is doable first.

Thanks!

Joe

[martin manning]

This has been posted here before, but this is one way to go about it.

[JoeTele]

Great! That is perfect. I would like to build this using a Princeton Reverb Chassis. Does anyone know if it would be possible/worth the effort to re-arrange the fiber board layout (possibly adding some extra eyelets) to mount the filter caps directly to it, or should those stay in the separate box? They'd be the newer, smaller style filter caps.

Are there other potential problems that would arise from using the PR chassis (other than having to potentially enlarge, punch some holes)?

Thanks again!

Joe

[martin manning]

Maybe someone has done it before, but I would just start laying out a scale drawing and see if there is enough room to either extend the preamp board and mount the filters to it, or perhaps mount a second board. I'd say it's worth a good look, as you'll probably be able to simplify the power supply layout some.

[M Fowler]

You don't want tremolo or reverb right?

[JoeTele]

That's correct.

Joe

[Firestorm]

Great! That is perfect. I would like to build this using a Princeton Reverb Chassis. Does anyone know if it would be possible/worth the effort to re-arrange the fiber board layout (possibly adding some extra eyelets) to mount the filter caps directly to it, or should those stay in the separate box? They'd be the newer, smaller style filter caps.

Are there other potential problems that would arise from using the PR chassis (other than having to potentially enlarge, punch some holes)?

Thanks again!

Joe

The PT will be bigger. If you don't want the doghouse, caps on board might be a shoehorn (but heck, Mesa crammed a lot of stuff in there). There's can caps, too, but you want to think through the grounding.

[JoeTele]

Thanks, M Fowler! That's awesome. Question, though. Is there any reason I can't just use the treble, middle, and bass controls as in the normal channel? I'd really like to be able to control the mids with more precision than a boost, and I wouldn't mind keeping the bright boost with the volume pot/switch. Also, can I just use a toggle switch for the bright boost? What type of switch would it be?

Thanks again!

Joe

[JoeTele]

1 other question. Will those filter cap values work with the GZ34?

Joe

[Firestorm]

Thanks, M Fowler! That's awesome. Question, though. Is there any reason I can't just use the treble, middle, and bass controls as in the normal channel? I'd really like to be able to control the mids with more precision than a boost, and I wouldn't mind keeping the bright boost with the volume pot/switch. Also, can I just use a toggle switch for the bright boost? What type of switch would it be?

Thanks again!

Joe

Mid control doesn't do as much as you wish. For that, you have to go James.

[Firestorm]

1 other question. Will those filter cap values work with the GZ34?

Joe

Super was designed for GZ34. Get a good one.

[M Fowler]

First of all make sure you listen to Firestorm's suggestions he knows his amps.

You could use 47uf/22uf/22uf/22uf instead of the 10uf as shown if you like.
You can drop off the 4 1n4007 diodes on the tone board and use GZ34.

I don't use mid much but you could just follow the SR layout and adjust as needed. The bright switch is SPST mini toggle switch or you can use a pot that has a switch on back of the pot. For pot switches you may have to use DPDT.

Mark

[M Fowler]

Superreverb's OT was 2 ohm so use a bassman OT, if you buy magnetic components brand you can get any value you want 4k primary with many different secondary values. I usually just get 4/8/16 even when building combos in case the owner wants to run other speaker cabs. Lots of choices available.

Mark

[JoeTele]

I don't know enough about filter caps to have any preference of sorts. I've just been studying the original and the Weber layout (which is where I'll get a fair number of parts) and I see that the filter cap values used with the diodes (and the resistors between them) differ from those. Is there any reason I shouldn't just use the stock filter cap/resistor values (with the GZ34 of course)?

Many thanks!

Joe

[Firestorm]

The Super tone stack was a little bassy to make up for the 10"s. If you're going 1x12", follow the Twin. The first Super Reverb had 40uF as the main filter. Close. The next model went to 30uF. Not enough. Go 50 or 60 (same configuration). If you have $150-$200, get a Mullard GZ34.This is an amp it makes a difference in. Less costly, NOS GE, or something Japanese from the 60s. Otherwise Chinese, or Russian. Have nothing good to report on the Slovakia ones. Seriously, a Mullard will last as long as the amp.

Going big on the first filter kills strangeness at high volume, but boosts the amps ability to pass bass, so don't go much past. 001-.002 for the coupling cap to the PI.