Do most tube driven reverb circuits use 8 ohm input tanks? Peavy Encore 65 uses 600oh

[Iplayloud]

4eb2c1b tank with "e" being a 600 ohms input. It looks stock and the schematic only mentions a part number. Do you guys think it's the correct tank?

[Enzo]

Does it work?

Accutronics pans all look the same, so I don't know why the wrong type would look any less stock. Most Peavey pans have not only the Accutronics number, like 4EB2C1B, but they usually have their part number a well. So is there a 71011114 on it?

It isn;t tube driven as much as it is transformer driven. The transformers usually have a low Z output and so need a AB pan instead of EB. That is what I would expect here. PV used a 4558 IC reverb circuit in most of their amps, and that used the 4EB pan.

[Iplayloud]

Yes it has 71011114 on it. Some googling confirms that this part is a 4EB.. thx

[Gingertube]

Plenty of ways to skin the cat (none of them pleasant for the cat).
I've seen a lot of different input impedances of reverb tanks depending on how it was driven. High impedance for a capacitor coupled from the driver tube anode, mid impedance for capacitor coupled from a driver tube cathode and off the secondary of a transformer when a Class A SE pentode driver is used or even a transformer coupled push pull 12AT7.

Like anything else in the guitar amp world there is huge inertia, that is, if it was good enough for Fender or Marshall to do it in this particular fashion then its good enough for us too - besides it gives commonality of parts and ready availability of spares.

That is why it is often interesting to look at some older designs from berfore "metooism" became endemic.

Here is (for example) an old Oz design (Moody) I did a circuit trace on during a repair
http://www.ozvalveamps.org/moody/moodyga40reverbcct.gif

The low (8 Ohm or similar) impedance input are simple to incorporate in to an existing amp as you can just drive them off the existing speaker connection without the need for a dedicated driver.
Ampeg did this a lot.

Cheers,
Ian

[Jazz P Bass]

Nice circuit diagram, GT.
Now that's a tech!
No schematic?
Make one.

[Leo_Gnardo]

FWIW some of the mid 60's Gibson (and near identical Epiphone) amps, GA-19RVT Falcon for instance, had a higher impedance tube-driven reverb transformer. It measures in the 400+ ohm region DC resistance (!?!) on the secondary, and replacement tanks have to be the higher-impedance types. This foxed me once so I'm passing it along for those who may need to fix these old Gibson/Epi's.

Also 60's - 70's Ampegs, which were direct driven (thru a DC blocking capacitor) off the plates of a 6CG7/6FQ7, need the hi-input-impedance tanks.

There's enough exceptions to the rule, plus modern IC driven reverbs, I keep both kinds in stock.