Ampeg Reverberocket GS 12

[gui_tarzan]

I had one of those in my shop last fall. What a PITA to get out! I ended up removing the mounts from the front baffle instead of from the chassis the 2nd time I R&R'd it. Much easier.

I'd try different tubes before replacing that speaker unless it's buzzing or actually defective. An acquaintance of mine bought ten of the ReverbeRockets from someone, all identical, and sold a handful of them to other musician friends of mine. The ones I've heard all sound great.

[goldenmonkeycolor]

I tried to reply a new post to this thread but it started a new thread instead. I have greatly appreciated your input so far, so lets get this amp perfect!

I'd like to get some more headroom out of this amp also. and it seems like a perfect candidate for a Electro voice type speaker. thinking about the eminence em12 (new ev copy) or the delta 12a or delta pro 12a. maybe a red white and blue? Some extra clean headroom and punch would set this amp off!

[goldenmonkeycolor]

[quote="Stevem"]All the caps in the tremolo circuit need to be checked for changed values and or shorts.

In regards to the brite reverb that's what I tend to love about these amps compared to most fender amps, but that being said you can change that.
If you look at the amps schematic you will see .47 blocking cap feeding the input to the pan and before that cap you will see a .02 going to ground.
To fatten up the reverb add another .02 across the one that's there and see where that gets ya.[/quote

So I am having trouble with my schematic. the one that was posted on the first page doesnt seem to match up quite well. I found the .47uf blocking cap but it isnt connected like shown in the schematic on the last page. there's also a .5 blocking cap that isnt connected like it is in the schematic. driving me crazy... the only .022uf cap i see is connected to a .5uf blocking cap but adding a .022uf cap in parallel didnt do anything for reverb brightness. i've included a picture of what i did.

does anyone have the correct schematic for this amp... this is killing me. i wanna replace the filter caps, but i'm scared with so much craziness in the schematic to actual layout.

the schematic also shows a .1uf cap between pin 1 of the first preamp tube and the 4M tremolo intensity pot- my amp has a .01uf cap here. will this difference affect the tone of the amp?

The reason I'm asking is because I dont feel like this amp has the bass content of other reverberockets ive heard. maybe i have a bad cap in the tone stack or something? those caps appear to match the schematic though.

Sorry for having all these problems and writing so much- just not sure where to go

[goldenmonkeycolor]

here's the picture of the reverb cap.

also i just realized! ::slaps head:: the schematic i'm looking at shows an amp with a 12ax7 and a 7199. My amp has two 12ax7's!

Sorry- now to find the correct schematic (doubt it will be easy)

[sluckey]

There are several versions of the Reverbrocket. Your schematic is probably in Hoffman's schematics library.

http://el34world.com/charts/TubeAmpSchematics.htm

Here's one schematic from that library that has two 12AX7s...

http://el34world.com/charts/Schematics/ ... t_12rt.pdf

[goldenmonkeycolor]

So I've dove back into this amp- I just replaced all of the filter caps finally- a while back i put an eminence red white and blues in it- and while it sounds great with a lot more presence and punch- this amp is just not made for a strident speaker. The reverb is SUPER bright even with increasing the .022uf cap that goes to ground-the one near the .47uf blocking cap before the reverb tank.

I also increased the .002uf cap that comes right off the reverb intensity pot (some schematics call it the dimension pot)- to .003uf and .005uf- and I may be wrong on this but it felt like it chilled out the dwell on the reverb a bit- or maybe tamed the decay. I'm not even positive of the difference there.

I feel like there is just wayyy too much treble in this amp for the speaker I have (but I know it was still way too bright with the completely muffled, dead CTS or utah or whatever was in it originally).

So now that i've got all the electrolytics replaced and am trying to keep this one going for another couple decades I'd like to at least try to modify it slightly to sound a bit more to my liking. (I'm playing a strat but I dont even have bright pickups in it- I've got high output bassy pickups (for strat single coil alnicos) So I dont think its just not the amp for me- as I can get a lot of sounds I really like out of it. and it does do a REALLY great clean sound and a REALLY great slightly broken up to moderately broken up sound- like a princeton reverb but a smoother breakup.

So does anyone out there have any more ideas on taming the reverb shrillness or the overall treble content of this amp? I dont see a bright cap I can clip anywhere.
=Things that would make this amp better- putting a pretty big high end cut on the basic amp sound maybe adding low mids and mids
- Taking a lot of treble content out of the reverb alone- the high end content in the reverb with the knob set anywhere above 20% of the way up can make the amp distort in that gross-
"this is just straight treble content disorting" way- the REVERB DECAY does that- it RINGS out
- so also being able to control the decay of the reverb would be great because the decay is huge and bright

The schematic I'm posting is close enough to mine- but there are a ton of different ones- Mine is the Gs12R with 12ax7's and a 6u10 and 7591 power tubes.

Anything even a quick guess as to what might help would be greatly appreciated!
Thanks

[goldenmonkeycolor]

heres the schematic

and check out this video
they say its the camera- and yeh maybe there is some bad digital distortion- but its just how the amp sounds- he uses single coils in the 2nd part

https://www.youtube.com/watch?v=SvYoNpiMIpE

Lets bring these guys back as a nicer lower priced alternative to the princeton with a 12" and a bigger cab!

[sluckey]

better schematic...

http://el34world.com/charts/Schematics/ ... _gs12r.pdf

[goldenmonkeycolor]

Yeh that is a nicer schematic- I saw one of those that had some wrong values though

Immediately I'm not seeing the .0001uf (100pf) coming of pin 6 of tube 3 (12ax7)

Maybe that would help with some of this reverb treble actually?

[FUCHSAUDIO]

Your tremolo is likely a bad cell. Fliptops no longer sells them (and their bugs were no great shakes anyway). I build and sell a replacement that works as well as the original, should you want to change it. Pm me if you are looking for one. Fwiw: in many Ampegs, the photo cell is in series with the tone stack, which may explain the bass pot wonkiness too.

[goldenmonkeycolor]

after replacing all the failing electrolytics I'm getting a good amount of bass.

I'm just trying to reduce this friggin treble- especially the treble in the reverb decay. Its killing me

I did just add the 100pf cap in between pin 6 of v3 and ground. I actually used 120pf i think- is that a high end snubber of sorts?

anyone have any ideas for shortening the decay of the reverb and taking out some of the super high end? I really dont mind bright reverb, but like I said this is way too bright

[Stevem]

Is the reverb pan a original silver/ gray colored pan, or Brass in color?
One thing you might try out either way is this.
Remove the pan from the amps wall and note the each of the two springs in the pan is actually made up of two shorter springs.
Take some 1/2" wide masking tape a put a rap of it around one of the springs on the input side of the tank and see how the reverb highs react.
You will drop off some reverb depth , be some highs also so you can even add more tape to get things where you want.
Just note to be careful when moving and holding the springs because they are held in at the ends near the transducer by very fine tempered wire that can snap easily.
Oh, and in regards to your first post of this string, if you still want to add a speaker output jack then the best place to do that so as to not have to drill a hole in the chassis is at the speaker terminals them selves.
You can even use a switching type jack that will cut out the internal speaker just by plugging in the 1/4' jack

[goldenmonkeycolor]

Is the reverb pan a original silver/ gray colored pan, or Brass in color?
One thing you might try out either way is this.
Remove the pan from the amps wall and note the each of the two springs in the pan is actually made up of two shorter springs.
Take some 1/2" wide masking tape a put a rap of it around one of the springs on the input side of the tank and see how the reverb highs react.
You will drop off some reverb depth , be some highs also so you can even add more tape to get things where you want.
Just note to be careful when moving and holding the springs because they are held in at the ends near the transducer by very fine tempered wire that can snap easily.
Oh, and in regards to your first post of this string, if you still want to add a speaker output jack then the best place to do that so as to not have to drill a hole in the chassis is at the speaker terminals them selves.
You can even use a switching type jack that will cut out the internal speaker just by plugging in the 1/4' jack

Thanks! Very cool idea! Yeh I’ve added a speaker jack, 3 prong, replaces all electro lyrics and got some bass back. I’m really thinking I’d like to tame out the treble of the entire amp now though. The reverb def needs a lot taken off the high end but so does the main signal.

I put an eminence red white and blues speaker in it. Which I like them in fender blackface amps but maybe it’s too strident for this Ampeg. Maybe... but I think the amp is just a little ridiculous on the treble tone stack. I’m gona try to use Duncan’s tone stack calculator today at my work computer. Thanks for the cool tip on the tank.

Got any cool tips for a tool to get into the weird hardware on these amps?

[sluckey]

You mean like the clutch head screws on the back panel? I've always just used a 1/8" (or 3/16") wide common screw driver and cussed a lot. Always said I was gonna get the right driver back when I owned a Gemini II, but never did. You can probably find the right size at an auto parts store. Or go to ebay…

https://www.ebay.com/sch/i.html?_from=R ... r&_sacat=0

[FUCHSAUDIO]

You can buy a driver online as the post says above. It's called a "clutch head" screw.

As far as brightness, some of these had a bright cap, which can be snipped. The RWB Is a pretty warm speaker, so I'm a little surprised if the amp is bright with that.
I would check through the circuit carefully. They are bright amps, but not painfully so.