Rocket w/ Reverb

[Normster]

I used an Accutronics 8AB2A1B (short tank, medium delay) but you could also use a 9AB2A1B (long tank). I tend to stay away from the 9AB3A1B (long delay) but you may prefer it.

[angelodp]

Ok, its been quite a while, but I finally got to the reverb add-on to my RJ-Rocket build. I followed RJ's original prototype and was quite happy with the amp. I did notice after quite a while that I had not implemented the 1/2 power set-up correctly and did put in the jumpers at the 100k/120uf pairs. This eliminated a little more hum and really had the amp at its best, chime, great tone and low noise level. After much PM consultation with RJ, MFowler, Structo,Colossal, Rawnster and Normster I proceeded to shoe-horn the reverb circuit into my existing build. I decided to try something close to Normsters version, even though I would have to re-arrange the topography a bit to accommodate the components in my existing build. Thanks for putting up with my barrage of question guys. Here is where I am at. The amp sounds damn good, albeit a little hum/hiss ( B flat ) on the the reverb circuit. When I dial out the reverb pot its dead quiet. I am open to suggestions on how to lower the noise level given my particular topography. BTW, I do have the boost switch w/ additional cap ( 22uf ) feeding 1k5, which is a nice added gain. Also have Normsters reverb tamer switch for higher volume levels. VVR & 1/2 power as well.

[IMG1084]http://i260.photobucket.com/albums/ii9/angelodp1/72.jpg[/img]

[IMG1275]http://i260.photobucket.com/albums/ii9/ ... G_7789.jpg[/img]

[M Fowler]

I normal only shield the V2 pin 2 to RCA + and that ends any residual hum I get. You have the 220k from V2 pin 2 to ground tab right?

I see that you already used shielded wire for the the leads to the reverb pot.
What kind of shielded wire is that I have never seen that type before?

[angelodp]

I normal only shield the V2 pin 2 to RCA + and that ends any residual hum I get. You have the 220k from V2 pin 2 to ground tab right?

Yes I believe that the 220k is correct, it grounds to the RCA ground tab. That V2 pin 2 to RCS run is so short .... 1 1/4" do you think shielding it will make difference. Would you ground one end of that.

I see that you already used shielded wire for the the leads to the reverb pot.
What kind of shielded wire is that I have never seen that type before?

Yes I did run shielding to the reverb pots, its from Apex. Honestly I think that the shielded runs there did not help and perhaps hurt slightly.

Also B+1 300 B+2 280 B+3 206 B+4 178 B+5 170

[RJ Guitars]

Hey Angelo - glad you got this together.

Somebody help me out if I am wrong but I think the power scheme is good. I wouldn't expect any power supply hum unless I am not seeing things clearly.

There was some talk about guys getting hum based upon the location of the reverb tank. If that is the case then you might try pulling the reverb tank and setting it on the bench away from the amp and running the leads to it remotely. If that works then you'll have to play with the location of your tank inside the cabinet.

Keep tinkering with it, that should ultimately give you a quiet circuit.

rj

[M Fowler]

Try a lower powered tube for the reverb 12AT7 instead of 12AX7.

Other than going through your work carefully looking for amy missed solders, component value incorrect, not wired correctly, a wire grounding out some where, reverb tank too close to the transformers, it would be merely speculative, on my part to assume that the short green wire is the problem area.

Sorry not a very helpful answer but I am trying to figure it out!

Mark

[angelodp]

There was some talk about guys getting hum based upon the location of the reverb tank. If that is the case then you might try pulling the reverb tank and setting it on the bench away from the amp and running the leads to it remotely. If that works then you'll have to play with the location of your tank inside the cabinet.

Hey rj, tried that with the tank off to one side and long cable.


Try a lower powered tube for the reverb 12AT7 instead of 12AX7.

Yup, have a 12AY7 in there.

What about the RCA output/input jacks and their grounding. They are chassis grounded. Its the only point that is not on the star/buss. Would isolating the jacks and running a grounds under the preamp board to the buss be logical.

thanks ange

[ChrisM]

Yes definitely isolate those RCA jacks. I do this in all my builds with verb. Works out quite well.

[angelodp]

Thanks for that insight Chris. Now once they are isolated, will bringing the ground out to the bus bar make sense?

a

[angelodp]

Thanks ChrisM for that suggestion.
Ok its quiet now. I did isolate the two RCA jacks from the chassis and tied the two grounds on the jacks together with a lead wire under the pre-amp board to the bus ( star-route ) ground. That took 95% of the hiss/hum right out. I can say that this amp now has such a minimal hiss/hum level that it is perfectly playable at home or in a venue. Wonderful tone ( to my ears ). I really need to do some sound clips.

briane wrote:
it really is a journey, and you just can't farm out the battle wounds.

But it sure does help getting forum friends to help along the way.

Here is the amended layout showing the isolated jack and new ground run.

And a pic of the VVR circuit around V1 to handle the DC on volume pot.



Just waiting for right angel RCA's and then get a new faceplate going.

[IMG1084]http://i260.photobucket.com/albums/ii9/angelodp1/72.jpg[/img]

[IMG914]http://i260.photobucket.com/albums/ii9/ ... tfinal.jpg[/img]
[IMG:720:582]http://i260.photobucket.com/albums/ii9/ ... RR-VVR.jpg[/img]

[amplifiednation]

Hey Guys,
I've been studying the layout and the schematic on Normsters Rocket Reverb as I wait for all of my parts. I'm still sourcing a few things that weren't available.

Questions

1. Is there a resistor used in the ground section of the filter caps? I don't see it on the original layout? I see an outline of something under the board on the reverb layout??

2. Does B5 come through the board and meet with the 100k resistor that is attached to the .005uf cap coming from the plate of V2?


3. THere are four wires coming out of the reverb driver. The black wire coming out at 10 o'clock is what? Ground?

4. I have a set of RJ trannies. Does the CT get used at all? For the 250 lines, I just cut them and isolate them?

5. The filter caps I have are already stuck together in a stack. Should I bother pulling them apart and putting them on a board?

Any help would be great!! Thanks so much.

[angelodp]

Hey Guys,
I've been studying the layout and the schematic on Normsters Rocket Reverb as I wait for all of my parts. I'm still sourcing a few things that weren't available.

Questions

1. Is there a resistor used in the ground section of the filter caps? I don't see it on the original layout? I see an outline of something under the board on the reverb layout??

Yes there is a 220k coming off of pin 2 that goes to the ground tab on the
input RCA jack. I linked the two RCA jack grounds and ran them back to the pre-amp ground bar near R7 ( you can see the light grey line )

2. Does B5 come through the board and meet with the 100k resistor that is attached to the .005uf cap coming from the plate of V2?

B5 normally terminates at R4, but I had to shift some of the reverb components into that area and used a jumper to feed that 100k/.005uf/220k network. Normster does it a little differently but I believe its equivalent.


3. THere are four wires coming out of the reverb driver. The black wire coming out at 10 o'clock is what? Ground?

Yes

4. I have a set of RJ trannies. Does the CT get used at all? For the 250 lines, I just cut them and isolate them?

5. The filter caps I have are already stuck together in a stack. Should I bother pulling them apart and putting them on a board?

Any help would be great!! Thanks so much.[/quote]

Hope that helps.

Ange

[amplifiednation]

Cool, Normster has the B5 jumpered from the bottom of the board from the reverb section to R4 from what I can tell, looking from your pictures electrically it seems exactly the same.

The capacitor I was referring to appears to be on the ground of the filter caps?? Ange, it's not in your build so I'm thinking maybe it's a error? Or maybe I'm just seeing things.

[amplifiednation]

I can't find the MOV/Varistor 150A/50V or power section cathode resistor 25W/50R. Do I need the MOV? It's not on the normster layout. If anyone has these parts or a mode pilot light let me know I will buy them!

[angelodp]

Are you referring to the opaque component that appears to be under the board? I believe that is a bleeder resistor.