Rickenbacker TR 25 Guitar Amp.

[paologregorio]

Anyone out there, other than Graham, have a TR 25? I wbought one two years ago on Graham's recommendation. Fantastic 25-watt amp. Solid sate, and sounds as warm as a tube amp. Nice vibrato and reverb.

Does anyone have one of these, and if so, do you have the original footswitch? I'm using a Fender Twin footswitch for mine.

[jdogric12]

Interesting. I'd love to hear what its 12" can do. I have 4 TR7's and love 'em (obviously, if I have four). One of them is a "Gem" though, not a Rick, but aside from the name is exactly the same as far as I can tell. I've been running a new pedalboard I wired up with 3 channels - via a Morley ABC, 1 channel is "guitar" through regular guitar pedals, 2 is "keyboard" which runs through things like a rotary speaker emulator, filter modeler, and synth sounds, and 3 is an octave pedal to a bass amp. The "keyboard" channel runs stereo to a pair of TR7's!

[paologregorio]

Interesting!

The only things I have to record video are my laptop and my IPhone; I doubt either is ideal for a sound sample. The TR25 is an excelent 25-watt amp; as warm to my ear as a tube amp. It's my main small rehearsal amp. I used it for practices when I was in OCBI with Joey Vasco and Mark Pytko.

[paologregorio]

Bump?

[chuck_king]

I have one. Nice and portable. The only thing holding them back is anti-solid-state snobbery, I think.

[Ontario_RIC_fan]

I own one too.

I used it in a stage play last year, with my 1977 JG 620. It nails the classic RIC tone.

Brian

[prowla]

I acquired one last weekend.

I've not tried it out yet; it was being used for demos on a seller's stand at a guitar show.

[cas]

I have one...was my first guitar amp--bought it in the late 70's. Unfortunately mine just went on the fritz and i need to fix it--it sounds great for bass but it think I over did it and rattled something loose inside after 40+ years

[paologregorio]

I just turned my TR25 amp upside down, and discovered the amp has an extension speaker jack, additional to the footswitch jack, which I knew about.

Does anyone know what ohm speaker is correct to connect to the amp?

[scott_s]

I just turned my TR25 amp upside down, and discovered the amp has an extension speaker jack, additional to the footswitch jack, which I knew about.

Does anyone know what ohm speaker is correct to connect to the amp?

The schematic is a little blurry, but appears to say 16 ohms when I zoom way in: http://www.rickenbacker.com/pdfs/19341.pdf

[paologregorio]

I just turned my TR25 amp upside down, and discovered the amp has an extension speaker jack, additional to the footswitch jack, which I knew about.

Does anyone know what ohm speaker is correct to connect to the amp?

The schematic is a little blurry, but appears to say 16 ohms when I zoom way in: http://www.rickenbacker.com/pdfs/19341.pdf

Thanks, Scott! Much appreciated. Interesting; I could replae the speaker with another I have on hand.

I wonder if the extension cabinet speaker would be 16 ohms as well?

Does anyone here own a Rickenbacker extension speaker cabinet? I've only seen the older type speaker cabinets, with the blue-silvery-gray tolex at RIC, I think.

Rick amps are quirky; there's a footswitch jack for the reverb/tremolo, but no one I've asked who has the same or similar Rick amps has a foot switch. When I asked, John Hall confirmed a Fender two-button reverb/tremolo footswitch would work, so I use one of those ... the same footswitch also works on my Ampeg Reverbojet.

[casinoman]

I have one, too. Bought it back in the late nineties in Switzerland. Whenever I record a Rickenbacker 12-string, I use this amp. It seems that the solid state technology suits the 12-string sound a lot, just as the Roland JC-120 does...

[espidog]

I wonder if the extension cabinet speaker would be 16 ohms as well?

Yes. Any extension speaker will be connected in parallel with the internal one. If the internal speaker is 16 ohm, using a 16 ohm extension will ensure equal power distribution to both speakers. With both speakers in use, the impedance seen by the amp's output stage will be 8 ohms, which will most likely be the lowest impedance the amp can be safely worked into.

Don't be tempted to connect an 8 ohm extension cab. This will result in two things:

1. Two thirds of the amp's power will go to the extension cab; one third to the internal speaker

2. The amp will be working into a load of 5.3 ohms, which may be lower than it's designed for. Working a solid state amp into too low a load can overstress the output stage and cause overheating/failure.

[4000]

Nice thread!

Bought a TR25 today, the version with black grill cloth with logo. I remain amazed by the contrast in prices of Rickenbacker guitars & basses vs their amps.

Allow me some rambling & questions, thanks! In case anyone feels like responding, for convenience I've added some numbers.

#1
Needs some work, on times there's a background-buzz as if the distortion was engaged, and currently the tremolo does not work.
Should all be fixable. Perhaps some adjustments will fix it already (power-stage bias, in case the background-buzz is due to too low biasing),
I saw there's also a tremolo-trimmer.

#2
Wondering about the serial number decoder on the Rick-website - I read somewhere it also works for amps, but not for the serial I entered.
[edit: just read elsewhere the leading zeroes should be removed, OK, thanks Ontario_RIC_fan!] result --> 1980

#3
Also read there are several reverb tank types mentioned for the TR25. My TR25 has the OC type 56.

#4
Speaker seems original (square magnet), codes SP122O16G and 12VPGI16A 67.7631
No idea about how to decode.... I figure '16' will refer to the 16 Ohm speaker-impedance, ... 7631 possibly to 31st week of 1976? (No idea which period the TR25 was produced).

#5
Power-switch has been replaced by another type (red pushbutton) - I'd like to re-install the original ON-OFF-ON type again, anyone has a closeup, or type-number of the original black switch ?

#6
Amp has a 10nF 'Death Cap', as also shown on the schematic. Will be disconnected/removed (see https://robrobinette.com/Death_Cap_and_ ... Switch.htm ).

#7
All pots PCB mounted, so was a bit surprised to see the absence of nuts, to avoid external force to the knobs potentially damaging the PCB. OK, all seems sturdy so far - perhaps my amp happens to be missing those nuts, but other TR25s do have them? Only the DISTORT-pot has a nut, all others have felt washers.

OK, enough for now, any response welcomed.

Bye

[4000]

FWIW, note that the TR25 schematic likely has a small drawing error in the tremolo-LFO section. (LowFreqOscillator)

Unlike the 'more usual' phase shift oscillator (topology with 3 cascading RC-sections), Rickenbacker uses a Twin-T oscillator.
As drawn in the TR25 schematic it won't work, the midpoints of the T's are joined, but shouldn't.

The horizontal line between "the two stacked 0.1uF caps" on the right, and "the 0.1uF cap that connects to the two stacked 1M resistors" should be removed.

The schematic of for instance the TR7 shows the topology that will have been intended. And is drawn in a fashion that more clearly illustrates the Twin-T nature of the oscillator.

Just sharing...