Peavey Renown 400 Reverb problem

[Shakey 1047]

I have just brought an old Renown back to life, the only problem is the reverb is really weak. I have tried a different spring unit but makes no difference. There appears to be plenty of output so I'm assuming the driver must be very weak. I have replaced the reverb chip but that had no effect. Does anyone know if it's possible to make the driver more effective. I have the schematic from Peavey. By the way it is the "solo" series, 2x12, 160watt.
Would be grateful for any help.
Cheers Dave.

[52 Bill]

Are you sure that the tank in the amp and the one you tried it with are the correct one for the amp?

Peavey uses a mid impedance input for most of their amps, unlike the low impedance input one that Fender uses.

[Shakey 1047]

Thanks for the reply Bill, I am assuming the spring unit that is in the amp is the original as there was at least 20 years of dust on it!! It is an Accutronics
4EB 2C 1B.
Cheers Dave.

[52 Bill]

That would be the right tank.

The only other tank question would be are you sure that it's plugged in correctly? Just be sure that the output feeds the return circuit and the input comes from the drive circuit.

[Shakey 1047]

Yes I checked all the connecting cables and made sure they were connected the right way around. I'm wondering whether to try the 8 series tank which is the 3 spring with the only difference being, the input is 800Z as opposed to 600Z on the original 4 series. I thought maybe I could have altered the driver circuit in some way to give it more drive, but I wouldn't know how.
Cheers Dave.

[52 Bill]

Changing to the 8 series tank will make the reverb more complex sounding, but probably will not change the amount of reverb that you have.

I'd check into the drive circuit, maybe a bad coupling cap.
Do you have the schematic for this amp?

[Shakey 1047]

Yes I have the schematic and the layout.
Dave.

[Enzo]

Then look at that schematic, the reverb is not driven from the IC directly, there is a little push pull transistor booster stage. Check both Q3, Q4. Measure each resistor, there are seven of them. DOn;t forget R72 down there. And while we are at it, check all four diodes for shorts.

Don;t go modifying the thing, just make it work as stock. Once it is running well, THEN consider any mods.


I could be wrong, but I think Bill was hinting that he might like to see your schematic. So here:

[Shakey 1047]

Thank you ENZO for your input, though the schematic you have attached is not the one for my perticular Renown. I shall attempt to attach the schematic for mine which I got from Peavey. It seems to be a very simple reverb driver which seems to be used in other Peavey amps such as the special 130 and the Studio Pro 50. I Have heard through the Steel giutar forum that the reverb on this particular amp was never very good any way, but I had hoped there may be a way to improve it rather than have to use a digital or other outbourd unit.
Cheers Dave.
By the way sorry for the delay in replying, I've had problems getting into the site.

[52 Bill]

Well that's about as simple a reverb driver circuit that you could create, even though it does have an unusual twist.

Have you tried replacing the chip, U5?

It may be the poor performance of this circuit is what caused the addition of the small push pull output circuit on the later version.

And yes Enzo you are always right... I was hoping that he would post the schematic to save me from digging through the box of Peavey schematics.

[Shakey 1047]

Well Gentlemen Thank you for your time and help but I reckon I'll have to get me an outboard motor. Shame but there ya go.
Cheers Dave.

[Enzo]

Sorry Shakey, your thread title said Renown 400, which is different from the Renown.

Working from your circuit then, did you verify the 10 ohm R86 is not open?