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Super Reverb head, watts & ohms questions

jaz761

Silver Supporting Member
Messages
260
Hi-

I've got a blackfaced 76 Super Reverb and a 73 SF Princeton Reverb. I love them both. Unfortunately, the PR is not really loud enough to go unmiked at the few gigs we play and the Super is a monster and much louder than I need. So, I want to use my 76 Super Reverb as a head and use a Mojotone 1-12" cabinet I have around. The speaker I have in there is a Celestion G12H-30 8ohm. My goal here is to not have to lug my Super around to gigs where it's way too loud anyway. Also I am starting to prefer the sound of the 1-12".

I know the Super is about 40 watts...the Celestion is an 8ohm, 30W speaker. I'm wondering if I run the risk of damaging anything by using my Super as a head into this single 1-12 cabinet. The SR is modded so I leave the master volume all the way up and use the channel volume to control output. I never go above 4...and usually not even that....on the volume.

Thanks in advance for any advice.
 

DRS

Member
Messages
12,374
Correct me if I'm wrong but the Super OT is set at 2 ohms for the 4 speakers it drives. An 8 ohm speaker is way to much of a load mismatch. On the power thing, up to 4 your probably OK.
 

soldersucker

Member
Messages
2,716
A 76 Super is rated at 70 watts not 40 it's usually printed under the speaker input.
DSR is right big mismatch but you shouldn't blow anything up.
Have you tried it?
 

jaz761

Silver Supporting Member
Messages
260
I've tried it and it sounds great to me...my Super actually says 45 watts on the back. Maybe it's not a 76...I never was clear on that.
 

smolder

Platinum Supporting Member
Messages
14,511
No, not all MV supers are 70 watts... I believe you're thinking of the ultralinears that came out 77/78. I haven't seen a schematic that shows any circuit changes after 1970 other than the MV and then the pull boost, so I'm not sure how they would increase wattage from 45 to 70 (in spite of what is on the ampwares site). Please correct me if you know differently.

My understanding is that the wattage printed on the back of fender amps is aspirational (marketing).

Many different opinions on the transformer/speaker mismatch... that probably more than I'd be comfortable stretching. My '73 Super Reverb head has a replacement transformer from Allen amps and I run a single 12 or single 15 a lot. You could go slightly under, over or match what is in there and have dual 4/8 ohm taps. Drop in replacement bolt patterns make it just a few solder joints to install. Or a good tech could do it very quickly.
 

Bluzeboy

Senior Member
Messages
7,850
I'm not sure how they would increase wattage from 45 to 70 (in spite of what is on the ampwares site). Please correct me if you know differently.
100% sure? nope.. I've read it on Ampwares and in the "Fender Amps the first 50 years"

That was the source for my statement which doesn't make it gospel by any stretch.
 

jaz761

Silver Supporting Member
Messages
260
I wish I could get a handle on understanding impedance and speaker/trans matches etc.

My Super Reverb definitely says 45 watts on the rear panel.
 

jaz761

Silver Supporting Member
Messages
260
Actually, smolder, your suggestion sounds good. Would you be able to recommend a transformer for me? Ideally, I'd like to be able to plug this Super chassis into the original 4-10s in the combo cab and also be able to use it with the aforementioned 1-12. Or maybe even the 2-12 cab (2 4ohm 12s, I think) that lives at the rehearsal space we use. Could this all be possible with a different OT?
 

kimock

Member
Messages
12,520
Hi-

I've got a blackfaced 76 Super Reverb and a 73 SF Princeton Reverb. I love them both. Unfortunately, the PR is not really loud enough to go unmiked at the few gigs we play and the Super is a monster and much louder than I need. So, I want to use my 76 Super Reverb as a head and use a Mojotone 1-12" cabinet I have around. The speaker I have in there is a Celestion G12H-30 8ohm. My goal here is to not have to lug my Super around to gigs where it's way too loud anyway. Also I am starting to prefer the sound of the 1-12".

I know the Super is about 40 watts...the Celestion is an 8ohm, 30W speaker. I'm wondering if I run the risk of damaging anything by using my Super as a head into this single 1-12 cabinet. The SR is modded so I leave the master volume all the way up and use the channel volume to control output. I never go above 4...and usually not even that....on the volume.

Thanks in advance for any advice.
Put the Super in a head cab and use the Mojo cab 8 ohm and the speaker in the Princeton for a total of 4 ohms.
The Super will handle that with no problem.

You've got two 8 ohm speakers. Use 'em both.
 

smolder

Platinum Supporting Member
Messages
14,511
Actually, smolder, your suggestion sounds good. Would you be able to recommend a transformer for me? Ideally, I'd like to be able to plug this Super chassis into the original 4-10s in the combo cab and also be able to use it with the aforementioned 1-12. Or maybe even the 2-12 cab (2 4ohm 12s, I think) that lives at the rehearsal space we use. Could this all be possible with a different OT?

ie: Kimock... I actually thought about getting head cabs for a couple of supe'd up princeton NR and Princeton Reverbs... then came to my senses and put the amp on top of a 1x12 or 1x15 cab if I need them louder.

I have the TO40MT in mind, which I think is about the same as whats in the bassman or super... if you want something slightly less 'big' there is a 35. Call David (Allen) - he's super nice and very knowledgable.

My Super (and a twin as well) are in head cabs because I have a bunch of speakers and like trying to figure out the combinations. Since I don't have a gillion years of road experience (like Kimock :) I don't know 'the one' speaker I'd want in a combo.

btw - there are a lot of different theories on the impedance match mismatch issue... this is a pretty interesting and spirited discussion amongst some folks with experience:

https://www.thegearpage.net/board/index.php?threads/1135306
 

kimock

Member
Messages
12,520
btw - there are a lot of different theories on the impedance match mismatch issue... this is a pretty interesting and spirited discussion amongst some folks with experience:

https://www.thegearpage.net/board/index.php?threads/1135306
The impedance mismatch issue regarding Fender 6L6 amps is 100% completely settled.
Here's all you need to know:
One step in either direction, no problem.
So, an 8 ohm load on a 4 ohm tranny, fine.
You can use a 2 ohm load, and the amp will run fine, but it'll sound a little funny because you're no longer in that 6L6's linear operating range.

Twice the impedance, 8 ohm load on the 4 ohm OT, or on the OP's case, a 4 ohm load on the Super's 2 ohm output is safe, and the output tubes are happy too.

Anybody tells you different, they're full of ****.
There is zero evidence to the contrary.
 

GearHeadFred

Member
Messages
1,643
I have repaired (blown screen resistor, bad output tubes) a SR that was placed in a head cab and used with an 8 ohm speaker cab.

SR into 8 ohms = bad ju ju!

You can use a Z-matcher, or replace the OT.
 

kimock

Member
Messages
12,520
I have repaired (blown screen resistor, bad output tubes) a SR that was placed in a head cab and used with an 8 ohm speaker cab.

SR into 8 ohms = bad ju ju!

You can use a Z-matcher, or replace the OT.
A bad tube can take a screen resistor at any impedance.
The mismatch wasn't the cause of the tube failure.

Or, however you want to say it.
Four ohms is fine.
I've run a Super Reverb at 16 ohms, dimed, for weeks at time just to push the point and couldn't get it to screw up.

Four ohms, fine.
 

jaz761

Silver Supporting Member
Messages
260
So my 2ohm OT is no good into my Celestion 8ohm. I don't want any problems...looking to simplify. Would the ideal speaker for my SR in it's current state (original OT) be a 2ohm speaker?
 

kimock

Member
Messages
12,520
So my 2ohm OT is no good into my Celestion 8ohm. I don't want any problems...looking to simplify. Would the ideal speaker for my SR in it's current state (original OT) be a 2ohm speaker?
Might be hard to find a two ohm speaker.
If you really feel compelled to run a two ohm load, a pair of 4 ohm speakers in parallel wouldn't be hard to find or lift.
Try a single 4 ohm of any size first tho, I'll bet you'll like it just fine.
 

SurfGreenTele

Member
Messages
2,306
100% sure? nope.. I've read it on Ampwares and in the "Fender Amps the first 50 years"

That was the source for my statement which doesn't make it gospel by any stretch.
Yup, that's true - it was only the '77~80 UL/CSA models w/solid state rectifiers that were 70w. The MV Supers up to around '77 were still tube rectified and 45w. The problem is that a lot of people date their silverfaces by the chassis serial # rather than the transformer, and they're way off. My '78 Super's chassis dates to '74-75, yet the transformer is late 1977.
 






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