[jb welder]

The idea that 6L6 and 6V6 are drop in replacements for each other can get you in trouble.
A 6L6 amp may have plate voltages that are too high for 6V6's.
A 6V6 amp's power transformer may not be able to handle the extra heater current required for 6L6's.

 

[Granny Gremlin]

What I've meant is I've seen amp schematics in Gar's book using the same transformer numbers for both 6V6 and 6L6 amps in the 45 & 90 series.
My rebel PA is a wedge chassis with the old style knobs, but unfortunately the tube sockets were not marked like they are in most (?) Garnets. No reverb either. Checking the bias is what lead me to believe this amp was originally 6V6 equipped. It also has a 6SN7 PI, which I think means it was an early model.

I think Gar drew up a schematic when he first designed each model of amp, and as you said was constantly making changes but never bothered to update the drawings. As long as they were close enough a competent tech could figure it out, he was probably happy. "As built" could vary.

There were occasional updates to the documentation, the changes were either transitional (documented later, like the phase inverter change you mentioned ) or relatively minor. For some long lived/flagship models we have 3 distinct eras not including cosemetics. There is, however, a huge info gap for the later period (both the low end solid state stuff and the later tube stuff) - like I've never seen an official schem for either the Enforcer or a Sessionmaster, and that's 80s/90s. Weird because that's still before the book came out, but I suspect it was a variable spec and the bits and pieces (e.g. various OD and channel switching circuits) are sprinkled about in the relevent chapters (but no single whole unit schem). There was some custom stuff, but again mostly involved features from other amps being added on.

Yes it is earlier and I have no doubt it was 6V6 based. So cute and tiny those guys. I have a reverb unit from that period.

... so I double checked and there was a G100PAR Rebel - found a schem.... but it was (like the Pro of the same period) the console style large front panel unit (in 4 or 6 channel versions). And now that I think about it I vaguely recall seeing a Tripper like that at one point (because it was so weird... like if you want the added tone controls per channel, how much more expensive would a Rebel be? And it's PA, like take the headroom/volume). So that's why the 'regular' head version of the PAR had to remain a G90. ... but had 6L6s... because otherwise it woulda just been a Tripper.

And of course @jb welder is correct and I shoulda clarified that myself.

 

[Frenchy99]

And yes, the change to 100 including a TX change as I said earlier.

If the Rebel PA ever was 6V6, it would have been the earliest ones with the triangle chassis, which none of these are.

Just verified mine, 1971 model, triangle chassis, PA90 model, pair of 6L6 with the 3K0979 transformer for the 6L6.

The name change to PA100 happened after 71. From 6V6 to 6L6 prior...

 

[Granny Gremlin]

Just verified mine, 1971 model, triangle chassis, PA90 model, pair of 6L6 with the 3K0979 transformer for the 6L6.

The name change to PA100 happened after 71. From 6V6 to 6L6 prior...

Fuckin hell, Gar, why do you do this shit. ;p

I think the TXes changed again with the G100 designation though. ...and that actually strengthens the original hypothesis of 6V6s not likely to be stock in later non-triangle chassis Rebel PAs.

According to the chart I compiled, the Guitar version Rebel II (G100) came out in 72 (head only, combo later) so that fits with everything. We still don't know if any Rebel PA90s** were even ever made with 6V6s stock (as an offical item off the model list, I'm sure he did it at some point as a one off at least) like the guitar versions were or not; I'd very much like to be sure about that one way or the other. The fact that the PA version of 6L6 head would fit in a triangle chassis makes it possible that they were always so - yours is 4 channel - not 2 channel (4 jacks)+phono like the early Tripper? ... Also now curious if the Tripper was ever anything other than a PA amp.

** Does yours actually say that ("PA90") because mine and all the other ones I've seen, and schems, all seem to be labeled G90PA(R)s; I have seen PA as a prefix in the model name for the bigger amps though and its useful shorthand. ... interestingly the later console style 6 channel Trippers were also G90PAR like the pre-console Rebel PA heads.

 

[Frenchy99]

Fuckin hell, Gar, why do you do this shit. ;p

I know...lol

The entire Rebel series was hard to follow...

 

[Granny Gremlin]

I know...lol

The entire Rebel series was hard to follow...

I'm tryin ova here!

So while you were posting that I editted my last post above so you may have missed it:

Does your 71 PA90 have 4 channels, or 2 (maybe 2 jacks each for 4 total, but only 2 gain knobs... plus maybe an optional phono input)?

Is yours actually labelled "PA90" on the serial number sticker?

 

[Frenchy99]

Does your 71 PA90 have 4 channels, or 2 (maybe 2 jacks each for 4 total, but only 2 gain knobs... plus maybe an optional phono input)?

Yep, 4 channels !

Is yours actually labelled "PA90" on the serial number sticker?

Yep !

 

[Lincoln]

Yep, 4 channels !

View attachment 352048



Yep !

View attachment 352049

That's exactly what mine looks like! It's also a model PA90. Power Transformer #6K2952, date code? DGJ1
Output transformer #3K0979 also with a date code of DGJ1

 

[zontar]

Garnets are cool.

Enjoy!

 

[Paul Running]

That's exactly what mine looks like! It's also a model PA90. Power Transformer #6K2952, date code? DGJ1
Output transformer #3K0979 also with a date code of DGJ1

I am curious to know if anybody has the detailed specs for those power and output TFMs or has anybody characterised them?

 

[Frenchy99]

Also now curious if the Tripper was ever anything other than a PA amp.

You are on to something !

Just finished checking all my files, every Tripper was a PA or Sound Console. Never an actual guitar or bass head.

You had the Swinger head and Lil' Rock head with the same specks.

 

[Granny Gremlin]

Yep, 4 channels !

Interesting, so the Rebel PA was always 4 chan and probably always 6L6; the Tripper in the triangle period was 2 chan (sometimes + phono, which I assume was mono but may have been stereo):

I say optional phono input because it really looks like an afterthought here being outside the silkscreened box. I wonder if the choice was master volume or phono line in with these things (like the Sessionman FTR vs later; Fuzz or Master, you didn't ever get both).

[PA90] Yep !

FAK! Just when you think you have a handle on it. So current thinking is early (triangle chassis) ones were PA90, then for some stupid reason they went to G90PA for the larger shell and new knobs era, and stuck with that even into the console era. Looks like this was consistant accross the range as regards Pro and BTO vocal amps.

The rebel PA head never changed from G90PAR to G100 because that was the designation for the Rebel Sound Console. The Tripper stayed as G90PAR as well.... except when Gar noticed he done goofed and changed it to T90PAR (at least by the time of the book ) to differentiate it from the later Rebel PA head.

 

[Lincoln]

I am curious to know if anybody has the detailed specs for those power and output TFMs or has anybody characterised them?

How could a person characterize them? Does it need more stuff than a good selection of resistors and a multi-meter or two?
I lifted one of the HV leads on the PT, 707 volts open circuit, 475V rectified, no load.

 

[Granny Gremlin]

I'm assuming someone could check with Hammond - they should have records and/or know which of their current line is roughly equivalent (what Garnet used was not weird; a lot of it based off the specs for Fender iron, and even those, initially at least, weren't Fender's specs but what most NA hifi and instrument amp makers were using. Sometiems Gar used Marsland trannies though so that's a dead end.

For power trannies it's pretty easy because most Garnet schema give you the output voltages. You'd also be good enough using the closest Fender style PT/OT for the given power section (e.g. Champ iron for a Herzog or a Gnome). Where it gets difficult is the quad/sextet 6CA7 big guns, but still there are comparables to look at.

 

[Paul Running]

How could a person characterize them? Does it need more stuff than a good selection of resistors and a multi-meter or two?
I lifted one of the HV leads on the PT, 707 volts open circuit, 475V rectified, no load.

The physical size of the TFM can fool you. I prefer to do a few tests...the size of the iron determines the magnetic flux capacity. A large iron core may not have a high current capacity...I've had a few unmarked 25Hz TFMs throw me off. For the PTFM, Static check the HV secondary DCR, a low DCR typically indicates higher current capacity. Load testing is a suitable dynamic method to determine current capacity. For the filament capacity, I use a rheostat to provide extra load to the winding...when you see the voltmeter drop quickly...you are past the surge load rating, back off a bit and then calculate the AC current or if you have an AC current meter, use it.

 

[Lincoln]

The physical size of the TFM can fool you. I prefer to do a few tests...the size of the iron determines the magnetic flux capacity. A large iron core may not have a high current capacity...I've had a few unmarked 25Hz TFMs throw me off. For the PTFM, Static check the HV secondary DCR, a low DCR typically indicates higher current capacity. Load testing is a suitable dynamic method to determine current capacity. For the filament capacity, I use a rheostat to provide extra load to the winding...when you see the voltmeter drop quickly...you are past the surge load rating, back off a bit and then calculate the AC current or if you have an AC current meter, use it.

ah, a rheostat. That would work well. I was thinking of providing a load with resistors and then measuring voltage drop.

Will a DC carbon pile work on AC?

 

[Paul Running]

As long as the resistance is low enough to force up to about 10A current flow @ 6.3VAC or 5A @ 12.6VAC...old alternator carbon stacks would work too.

 

[cboutilier]

I think it is neat that the Tripper PA has a Slave Out too.

 

[Granny Gremlin]

I think it is neat that the Tripper PA has a Slave Out too.

That is neat and frankly, it could really use it due to low power internally.

My Rebel PA has a headphone out (switchable with speaker out not concurrent). I always assumed that was not stock (also it is stoopid loud, can't play guitar dirty at all with those on), but I am planning on going in there to do some things so I'll have a better look. It would be super usefull if I could pad that a bit so can listen on cans with higher gain.

 

[cboutilier]

That is neat and frankly, it could really use it due to low power internally.

My Rebel PA has a headphone out (switchable with speaker out not concurrent). I always assumed that was not stock (also it is stoopid loud, can't play guitar dirty at all with those on), but I am planning on going in there to do some things so I'll have a better look. It would be super usefull if I could pad that a bit so can listen on cans with higher gain.

I wonder where in the circuit the Slave is drawn from.