thanks for responding. The voltages at T8 are:
pin 1 - 5.86
pin 2 - 1.49
pin 3 - 0
After adding the jumper as described above, I have good signal on the recovery side all the way to output. When I trace the signal from the guitar input jack, I have signal all the way through to both reverb outputs. The signal seems really weak though. I am not sure how much the signal should be amplified, but I’m getting roughly the same signal voltage at the transformer output that I am putting in from the signal generator. This is with the dwell control at max and the mini pot at minimum, which gave me the most signal. On the scope, the signal looks very distorted at these settings.
is it possible that I have a bad pcb? If there was that open connection on the recovery side, I’m wondering if there is something printed incorrectly in other spots as well.
That trimmer seems to work to increase the make up gain after the reverb effect. My problem is that I have a very small signal driving the reverb before the transformer. If I input a signal from a generator at 100mv 400hz, at the transformer output I get 70mv at max drive settings. Do I possibly have a bad transformer? The signal is very strong at the primary, but weak on the secondary side. I get a resistance of 1.5ohms between the secondary and ground. I think that seems ok or an 8ohm transformer, but I’m not sure.
thanks for the reply. I’m lost then. I seem to be meeting all the right conditions to have this thing working. I have signal on the input side all the way through the transformer out. I have lots of signal voltage at the transformer primary as you described. I have tried an 8ohm tank, a 10 ohm tank, an 800ohm tank at the capacitor output, and I’ve tried multiple sets of cables. I can’t seem to drive any tank enough to get signal back into the recovery side. If I plug a signal generator directly into the recovery side, I get signal all the way to the output, just as I would expect. Is there any suggestion that I may not be looking at? Grounding issue with the tank or cables?
Sorry to keep bothering with this. Everything seems just fine and I’ve troubleshooted everything I can think of.
here’s what I have at those transistors:
E - 1.007v
B - 1.603v
C - 3.810v
E - 3.2
B - 3.81
C - 5.47
The tanks are good. I’ve tested them with current amps and did so again before I replied to this. With a 25mv signal directly to the recovery input, I only get distortion with the trim pot all the way up. I can clean it up by turning it back 10% of the way.
thanks again for spending time on this with me.
Well, I finally got frustrated and tore the whole thing apart again...and found a little sliver of wire bridging the connection from the power inlet ground and the pad that connects to A+. I’m sure you figured it was something stupid like that, but humored me anyways. Now I have plenty of power to push the tank. It’s really great. I actually housed it in a box big enough to fit a short tank internally, then I put a switch in place to move the signal to the jacks and it works great. So now I can use it for a nice splashy ambience with the internal tank, or I can hook up a long tank for some serious drip.
Thanks again for the great support. Sorry it was something so simple.
Happy to hear it's up and running. If you can still access the board would you mind posting the voltages at T1, T2, T6, T7 & T8? I'd like to compare them to my build once it's complete. And I'll post my voltages as well for future reference. Thanks.
I'm very close to moving forward with this reverb but haven't been able to find any demo/comparison of this circuit. Is it similar to a stand alone reverb unit, an amp reverb circuit, or is it's own thing entirely? Thanks for any help describing what this would sound like.
I recently finished to build the Analog reverb kit (including the blue tank) and I notice some bad distortion when setting dwell 1 fully clockwise and the other two : dwell 2 and mix anticlockwise at minimum.
Is it something to be expected? The amount of distortion remains the same regardless i'of the trimmer settings.
Thank you in advance for your help,
@bjf hello Björn,
I am currently building a reverb tank using your universal reverb driver kit and I would love to clear something up.
I really want to add an EQ section to this circuit and get crazy with it. My idea was to build your wonderful Sea Blue EQ circuit and place a HPF in front of it and a LPF after it, to reduce noise when the highs are boosted. Creating a little 4 knob eq section (fixing the volume on the SBEQ)
My question, as a noob, is this: where can I connect this circuit in with the Reverb Circuit, so that the EQ section only affects the wet reverb signal before it is mixed together.
Also, maybe related: what are the “tone” and “aone”(?) pads on the universal reverb pcb? I don’t see anything in my build guide about those pads.
Thank you so much!
Oh tone control for reverb is definitely possible by just adding desired filter outboard inserted at Reverb level control.
I'll have a talk with Albin about making a tone control modification kit and getting schematics up for those that have parts lying about.
Worth mentioning is that the reverb effect from a typical tank has a fairly narrow bandwidth and low frequency reflections have tendency of causing mud whereas high frequency reflections a tendency of causing shimmer: therefore most effective would a treble control be and also limiting low frequency response to make effect appear more as shimmer
A difference between tanks is also how high up in frequency they go so it can be useful to have control for brightness.
Slight caution is again that tanks have limited bandwidth so boosting treble a lot after recovery can be just amplifying noise therefore
making a sort of bandpass boost can allow boosting the relatively important part of response i.e. highlighting where there is energy but not heating for the crows.
At your service
Wow thank you for taking the time to given me these suggestions. I think I am gunna try both before the reverb driver and after to see what gets the best result.
I already have a wonderful SBEQ up and running on tag board, and thought I’d try and make this reverb really crazy.
thanks so much, 🙏🏼🙏🏼🙏🏼