Is a Super Reverb OT (MM, with 4,8,16) OK to use in a build?

[pine]

That would be a great one to use as a template.

Does adding a sag resistor 100 ohms@10watts in series to the OT center tap simulate the sag of the Super?

I guess the preamp could be duplicated, but am a little worried about what the 22 uf bypass caps are going to do to the OD tone.

I'm not sure what you meant by the PI input 1n=.001uf

Is there anything else that needs to be added into the equation?

[talbany]

A few more things
1 Axe the Skyline stack
2 Axe 220K 500pf grid Resistor V2b
3 Add parallel Spring reverb adds 1/2 stage of gain....This is a big one
4 Axe the master volume... Put a 1 meg load on the PI doesn't feel like a Fender anymore Toto...Another big one
5 V1 voltage needs to be raised to around 270...This is a big part of why these amps are so smoooth.. Another big one!!
6 1000pf PI entrance cap sounds smooth for clean channel but will make the OD sound a bit on the thin side..
7 Move away from the stock 1.5k NFB resistor to a presence control small change but I can tell
8 12 AT7 on the PI
9 Carbon Comp resistors... Another big one!!

Take any one of these throw them in the soup no big deal add em up and you have a small problem...
The only way I see to do it is to have an independent clean built w/reverb if you want to get close..Changing transformers and a Sag resistor is a brick in the Grand Canyon..


Tony VVT

[pine]

If you compromised on the reverb and used an effects loop instead you could take care of #3

I don't have a problem axing the skyline stack as I play a strat or a 335

We can't axe the Master volume or raise V1 to 270 and still have the right OD section

I'm thinking that you'd have to do what you said, and what Mesa does with their Lone Stars, have two independent channels in one chassis, sharing tubes, speakers, and transformers. probably beyond my skill set

[bluesfendermanblues]

I'm not sure what you meant by the PI input 1n=.001uf

The 1n input cap on a blackface super/deluxe/twin is an important aspect of the blackface sound.

[pine]

The 1n input cap on a blackface super/deluxe/twin is an important aspect of the blackface sound.

I see, sorry, I'm a little foggy today, not enough coffee

[Structo]

I think that was Bob that drew that up.

Don't know if it was ever built though.

[BobW]

I think that was Bob that drew that up.

Don't know if it was ever built though.

I believe you're right. That layout may have been the peavey chassis that Bob-I gutted a few years ago.

[dogears]

All manner of deleted posts and references deleted.....

Kumbaya gentleman. Carry on.....

[Bob-I]

I think that was Bob that drew that up.

Don't know if it was ever built though.

I believe you're right. That layout may have been the peavey chassis that Bob-I gutted a few years ago.

Not exactly. I built that one in an Allen Old Flame head cab. Honestly the Super Reverb channel sound nothing like a Super Reverb, more like the Dumble clean, I suspect because of the PI and the reverb. I like the amp, it's just not what I was shooting for.

[pine]

Ok, (and feel free to mock the noob), but with regards to the attempt to incorporate a Super Reverb clean channel with a Dumble overdrive, if I understand you correctly, the PI section is so different between the two that unless you are switching somehow between 2 different PIs when you change channels, you can never preserve the cleans of a Super and still have a Dumble OD.

I'm not sure you could even switch something like that on the fly, but the only thing I can think of is two switched PI "modules" like Randall Amplification does with their preamp modules, unless there is some tube out there that can do the job of two PIs. Is this possible or am I terribly ignorant of some other mitigating factor?

[Bob-I]

Ok, (and feel free to mock the noob), but with regards to the attempt to incorporate a Super Reverb clean channel with a Dumble overdrive, if I understand you correctly, the PI section is so different between the two that unless you are switching somehow between 2 different PIs when you change channels, you can never preserve the cleans of a Super and still have a Dumble OD.

I'm not sure you could even switch something like that on the fly, but the only thing I can think of is two switched PI "modules" like Randall Amplification does with their preamp modules, unless there is some tube out there that can do the job of two PIs. Is this possible or am I terribly ignorant of some other mitigating factor?

This thread has me thinking... sometimes not a good thing..

The key differences here are the voltage divide Fender uses after the reverb, made up of 3.3M and the reverb return circuit. This lowers the gain of the reverb return to ~0, and the PI entrance cap. I wonder if I add a cap after the Fender channel to limit the bandwidth going into the PI, and use a voltage divider, if I'd get more of a Fender type tone on that channel.

[PaisleyTube]

With stock bf/sf or MM iron the stack-size is the same for the Bassman and SuperReverb OTs but the style of interleaving does differ.

A client did use a custom MM OT and choke in his CT-D-clone (besides some other mods) and it did improve the sound largely.

The are small differences between a SR OT (just 2 ohms) and a SR with other/more taps.

Anyway: lots of companies do offer "general" Bassman/SuperReverb OTs but a '59 Bassman OT differs from a blackface SR OT....

[talbany]

This thread has me thinking... sometimes not a good thing..

The key differences here are the voltage divide Fender uses after the reverb, made up of 3.3M and the reverb return circuit. This lowers the gain of the reverb return to ~0, and the PI entrance cap. I wonder if I add a cap after the Fender channel to limit the bandwidth going into the PI, and use a voltage divider, if I'd get more of a Fender type tone on that channel. Idea

Maybe something like this/ input on the Super side would be 00010939 uf



Tony VVT

[Bob-I]

Maybe something like this/ input on the Super side would be 00010939 uf



Tony VVT

Thx Tony, looks great only I'll have to figure the reverb entrance. Right now I have it just before the PI with a 150K resistor. Hmm....

I also have a D-lator loop. So much to think about.

[talbany]

Thx Tony, looks great only I'll have to figure the reverb entrance. Right now I have it just before the PI with a 150K resistor. Hmm....

I also have a D-lator loop. So much to think about

Bob-I
Thought I'd mention.. If you set up the output section like this and run both channels through a dual 1 meg pot as a master for both channels..I've tried this on several amps and it works great.. If you do it like this which ever channel you have the reverb on you can crank the clean channel turn down the master and just hear the reverb... This makes it much easier to choose which value mixing resistor to use to get enough reverb in the mix and not so much that it doesn't distort on you...Most of the ones I've set up like this I use 120/150k so your all over it.. Anyway thought I would just mention it's a cool mod!!... Good Luck!!!
I'll shut up now!!


Tony VVT