Premier 100R.. anyone have any info?

[Indyryder02]

Restoring an old premier 100r… haven’t found any type of schematics etc.
I’ve managed to get it mostly working.

problem I have now besides a bit more hum still that I’d really like..
is hardly any volume when the reverb is switched off.

strange circuit that’s running high voltage through the pedal from one of the filter caps.

never encountered a design similar so not sure what to check for.
especially without any type of schematic for an idea of how it’s working.

I’ll do more testing in that area tomorrow to hopefully find something. Nothing so far. And not sure which direction to go.

This is definitely a wild amp. 10 tubes total.

[The Dude]

I don't have a schematic, but it's a 60 year old amp, so there's a good chance you have electrolytic caps that are shot. Have you checked, substituted, or replaced any of them?

[Indyryder02]

Yes. All the electrolytic were way out… replaced both main multi can filter caps as well as the couple of the smaller ones inside the chassis. The rest (non electro) seem to test pretty close.

so for reference. The amp has 2 channels.
channel one has two inputs. And has the reverb and tremolo.
ch2 has no effects and only one input.

ch2 seems fine.. ch1 seems to match ch2 in volume etc when the reverb is engaged. But when the reverb is switched off via the pedal. The volume fades away with the effect.
maybe that’s a clue, usually reverb switches on or off not fades away.. but not used to this setup with the high voltage about 100ish. Running through the pedal. It jumps to about 60v and back when switched.

new one for me for sure.

[DrGonz78]

Perhaps there is 6AQ5 as the reverb driver? The model 90 is a reverb amp and I am pretty certain that is the reverb section that is in the 100r. Take a look?

[Jon Snell]

Could it be similar to this one?
Hand drawn a number of years ago, not sure of the serial number it was reverse engineered from.
premier_120r_sch.pdf

[mozz]

The 120 or was it the 160 has 3 or 4 different schematics, so I would expect most models from Premier are likewise.

[Indyryder02]

Perhaps there is 6AQ5 as the reverb driver? The model 90 is a reverb amp and I am pretty certain that is the reverb section that is in the 100r. Take a look?

Yes! That appears the same as what I have, 6EU7 and 6AQ5
i did have to replace the one with a 6AQ5A. Which from what I gathered from the manual has a different heater setup but was the replacement for the 6AQ5

this should help a lot. I almost thought of looking at the reverb amp but assumed it’d be different. Derp!

[Indyryder02]

Could it be similar to this one?
Hand drawn a number of years ago, not sure of the serial number it was reverse engineered from.
[ATTACH]n975729[/ATTACH]

I’d looked at one of the hand drawn ones of the 120 but it seemed way off. This is much more similar. Thanks

[g1]

Does the tremolo work? The trem footswitch?
If there is going to be any DC at the footswitch I would think it more likely for the trem than the reverb.

[Indyryder02]

I got it. Found a resistor that was completely mixing. Someone was obviously trying to fiddle with the reverb circuit before, the guy mentioned his son was trying to fix it at once. Thanks for the schematics, really helped point me in the right direction.
you guys are the best as always!!

[Indyryder02]

Does the tremolo work? The trem footswitch?
If there is going to be any DC at the footswitch I would think it more likely for the trem than the reverb.

Yes. Everything works now as it should. Nice and quiet too.
thanks again!

[Indyryder02]

Ok.. thought I had it…

it sounds absolutely amazing…. Beautiful reverb and tremolo.

but…. Something I’ve never encountered before… after several minutes of playing. It cuts out.
cycling the reverb switch brings it back… every time.

so does trying to probe anywhere I’ve tried so far..
so not making it easy!! Haha

i haven’t found what voltage where etc is cutting out yet (I assume that’s the case and will lead me to the issue)

I have no clue what could be causing this yet. Have any of you encountered this type of issue before? Bad capacitor? Some sort of weird static buildup and discharge? Not likely. Wth?

[Indyryder02]

Any clues? Pulling my hair out… listening to a podcast through the amp.. it cuts out at random times….
I’ve so far figured out, when the signal cuts out… I can probe plate voltages on all tubes except the two in the reverb section it seems, without bringing the amp back to life… as soon as you touch a probe anywhere in that area the signal comes back. And of course then you can see what it’s losing etc. Never seen anything like it. What could that possibly be? I just know it’ll be something dumb in front of my face no doubt when I do figure it out. ♂️

[g1]

Maybe oscillation overwhelming the main signal?
The 90 schematic mentions the input to the tank does not have the sleeve grounded, is yours like that?

[Indyryder02]

Maybe oscillation overwhelming the main signal?
The 90 schematic mentions the input to the tank does not have the sleeve grounded, is yours like that?

I’d read that as well. It is connected at the chassis to a grounding terminal.

I also discovered the ground was broke inside the output rca Jack at the pan.

Repaired the ground connection at the output rca Jack and disconnected the input sleeve from ground.

no immediate changes, however it hasn’t cut out in a while now before this change so really not sure.

will have to run it more to see if there’s any changes.