1-tube reverb problem

[firemedic]

So I put in the 1-tube reverb circuit today & it does not work.
The tank does make (amplified) noise when shaken. So it seems like the problem must be reverb input gain.
I disconnected the 100k dry signal bypass to see if I had ANY reverb from the input, and I do. But very low volume. It can't compete w/ the dry signal.
I've quadruple checked all my connections & tried all the alternate component values to maximize gain, still nothing.
It's a brand new fender reverb transformer & accutronics short reverb tank.
Red to OT B+, blue to the plate, P1 356V. P3 cathode has 5V(?) I have 1k/25mfd there. Black to ground, green to tank input. P6 186V, P8 cathode 2.3V. 12AX7 EH tube. I even replaced the used pots with no change. Changed the dry signal resistor to 220k, nothing. You guys make it sound so easy.
Any ideas?
 

[tubesornothing]

It is easy.  Can you post up a schematic?  Tube voltages would be good too.

Sounds like its just not getting signal to the input. (very carfully) You can use a grounded screw driver to tap the input tube grid and it should produce a click sound.  Only do this if you are really comfortable with which pin is which.

[StevieRayVehkakoski]

If your reverb-tank is 8 ohms, you can replace that with a speaker and test the driver-side of the reverb. The recovery-side is obviously ok if it amplifies the tank. Also check carefully the RCA-connectors and cables + which side is grounded on the tank.

[tubenit]

I also would like to see a schematic of the entire amp with reverb and perhaps a photo of the reverb section in the chassis build. If you are using shielded cables to the dwell or reverb pot ....... make sure that they are not shorted.

With respect, Tubenit

[tubenit]

Is this the schematic you are using?:

http://www.schematicheaven.com/fenderamps/tremolux_5e9a_schem.pdf

Because if it is, I think you may have a tough time making a one tube reverb work in that amp?

Where did you insert it?  There may not be enough gain after the insertion points to get you enough reverb?

With respect, Tubenit

[firemedic]

I initially used the 5E9 circuit but that went away real fast. The only thing left intact from that is the driver/tremolo. The power section is set up for 6L6s.
The preamp is basically a AB763 2-input normal channel only, 2 gain stages, separated cathodes, w/ tone stack in between them. I am still using a 12AY7 for the 2 gain stages. I will try a 12AX7 there.
The reverb is inserted between preamp & driver. It is your (tubenit's) 1-tube reverb.

V1- 12AY7 EH. V2 (driver)-JAN 5751. V3- reverb- 12AX7 EH. V4- tremolo- ECC83.
I haven't drawn up a schematic yet, that was pending completion of this project. And it is a rat's nest of random wires at this point, until I have the tone & reverb dialed in. This is my 1st build so I think I've done pretty good. It looks like hell though.  Suffice it to say that it works fine w/ low/moderate hum, even with the reverb in there & guts all over... Plenty loud, pretty good tone.
I tried jumpering past all my shielded wires (dwell pot connections, output to driver are long runs), no change.

The reverb does work, it just is too anemic to be heard over the dry signal.

[firemedic]

BTW, I do get a faint pop when touching pins 1 & 2. I just thought of something, what is the rule for the shield ground connections on the RCA cables?
also, I get less than 1 ohm on the tank input, 215 ohm on the output, using a VOM. Something shorted in the tank mebbe. The saga continues.....

[sluckey]

The reverb is inserted between preamp & driver.

Can you show or tell us exactly how it is inserted?

I get less than 1 ohm on the tank input, 215 ohm on the output, using a VOM.

That's correct for an 8-10 ohm input and a 2000 ohm output.

[tubenit]

Firemedic,

The one tube reverb I have used has worked on every amp I have installed it into without exception.

It sure would be easier to help you if you showed us an actual accurate schematic to look at.  Since you have not done that, I will provide one as a starting place example for communication and diagnosing this.

Forget the values ............... does the overall topology look like what you have?
In other words,  gain stage  then  tone stack  gain stage  into LTPI?  With the reverb insertion point similar to what I have shown?

Do you have a master volume anywhere?  If so, where?
What type of phase invertor does this have? 

PLEASE provide more current information and/or a schematic. It is not uncommon on this forum to miscommunicate without having an actual schematic to look at. Sometimes a schematic gives someone a quick solution or diagnosis to the problem.  Sluckey in particular has rescued some of my initial  build glitches by glancing at my schematics and pointing out the problem.

Are you inserting the reverb similar to what I have drawn?

With respect, Tubenit

[firemedic]

Sorry for testing your patience. I do not have a schematic, not yet. It will be hand-drawn.
The insertion is just like Jeff's CBS except I may keep the 220k divider there. 
At any rate, the reverb works now, very well. I had used the board terminals for a buffered effects loop which I scrapped & thought I had accounted for all the connections under the board. Except the one the input connected to, which had a hard connection to ground.
For what it's worth I never doubted that it is a good reverb design, I was just looking for common mistakes inexperienced builders make that you fellas could clue me in to..... Like hooking the input to ground. OOPS. Once I cut the ground everything was fine.
I can see the end of this thing, should have tone the rest of the way dialed in soon. I had a hell of a time before since the 500pF cap to the dwell pot was sucking out all my highs without my knowing. Will post a schematic as soon as I have it drawn.
Sorry to have wasted you guys' time, I am not the sharpest knife in the drawer as my wife will attest.

[tubenit]

Very glad you got it fixed and working OK!  Thanks for letting us know your resolution.

There are lots of editable schematics you can use (edit) to draw yours up from the SCH library of schematics.

With respect, Tubenit