Marshall 18watt Reverb

[JMPGuitars]

This is what I've come up with. I have tweaked the schematic a little bit (and the layout a bit more) since my first prototype, but only due to tremolo thump. The reverb worked nicely straight out of the box (well once I moved all things tremolo away from all things reverb).

18 watt reverb - 6v6 schematic v1-4.pdf
18 watt reverb - 6v6 layout v1-4.pdf

You should have read a little more.

We were discussing removing some of the reverb circuit's tone-sucking resistors and sending the return through the unused triode of the PI on single-channel, non-NFB amps (especially our 18 watters)... Your signal origin point is 1 option, but it's nice to experiment with the signal before and after the tone stack to see how that affects the reverb tone. I've already done all this (including removing the extra resistors), now it's his turn...and maybe yours too, if you want to improve the reverb tone even more.

[fiat_cc]

Well, since I’m here now...
If I wanted to bring the reverb return directly into V3b in my schematic (spare triode of phase inverter), do I change (or delete) any of my resistor values?
Also, is there a benefit in tapping the reverb signal before the tone stack? I imagine that would leave you with less possibilities in terms of reverb sound.

[geoff 1965]

hello pilgrim's
this might be useful/interesting to the topic? it's the hoffman 18watt lite reverb which i saved for the V1 cathode biasing "has anyone tried this?"
note how the reverb circuit uses both halves of the phase inverter mentioned earlier in the post.

18w lite reverb.GIF

[SkilpaddaN287]

Yes exactly
And reverb circuit look much easier to do than the blackface reverb cicuit
Is there any info somewhere about what reverb tank(pan) to use and other stuff...?

[fiat_cc]

It looks, at a quick glance, to be the same reverb circuit I used (and posted a few posts ago). The main difference being I fed it in on the other side of the phase inverter. Tank model is on my schematic, and the transformer is the same as the standard Fender reverb transformer. Also, I don’t see it using both sides if the phase inverter. ‘C’ refers to a power node. R2 feeds back into 1 side of the phase inverter (the opposite side to the rest of the amp).

[geoff 1965]

SkilpaddaN
glad the schematic was of good use for you! i have'nt built an amp with reverb but i'm sure the rest of the guys will help you out. if you go to the "EL34 world" website there are schematics,layouts and parts lists for the hoffman reverb amps.
good luck

[SkilpaddaN287]

But i some wonder if this reverb will have some weak signal compared to the fender...?
Fender have two triodes in paralell for extra current before the transformer and an extra triode after the recovery triode....

[fiat_cc]

But i some wonder if this reverb will have some weak signal compared to the fender...?
Fender have two triodes in paralell for extra current before the transformer and an extra triode after the recovery triode....

It is not as strong as the Fender blackface reverb. I find that there’s plenty available for my personal taste, but if you’re wanting Fender amounts, this circuit won’t get you all the way there.

[SkilpaddaN287]

Did some old fashioned drawing...
Have to tune the power supply to get good voltages but on my view it should work...

[Banker]

I have an original 18w "Master Reverb", a 1958 in 2x10 format. It's an interesting amp, single channel with both reverb and trem. Interesting layout too. A friend knocked up a schematic for me, which I'll do my best to find and post here in due course.

In the meantime, a couple of pictures.....

[JMPGuitars]

I have an original 18w "Master Reverb", a 1958 in 2x10 format. It's an interesting amp, single channel with both reverb and trem. Interesting layout too. A friend knocked up a schematic for me, which I'll do my best to find and post here in due course.

I'd love to see the schematic when you get it. Can you post some sound samples? I'd love to hear the reverb half way, and fully cranked.

Thanks!
Josh

[sreiter]

I havent been on here in a longggg time.

My buddy has a orginal 18w w/reverb.

If my gallery is still on here, there's pics, including chassis

[JMPGuitars]

I havent been on here in a longggg time.

My buddy has a orginal 18w w/reverb.

If my gallery is still on here, there's pics, including chassis

Do you remember what your album was called? The old archive galleries are here: gallery/

Thanks,
Josh

[Malibu2006Vride]

Hello I just joined this site and am planning to build an 18W amp. I'd like to add reverb and found this thread. It looks like it went stale back in 2018.

Does anyone have a schematic for the original Marshall design with the reverb option?
I'd like to stay as close to the original as possible as opposed to kluging in something.
I'd appreciate any help from you all.
Regards
Dave

[Daviedawg]

I do not recall any approved or tested circuits while I have been on the Forum. But even so there may be one buried somewhere. Unfortunately some early material in threads was not recoverable after a hack several years ago.

Having said that it would be a useful circuit to have. What form of 18 watt were you considering? If it is an 18 watt lite then all the standard iron should work fine. But if a trem or TMB then you would have to consider the power transformer needs first since you are adding at least one twin triode and possibly also a triode pentode depending on how good a reverb you would like.

I have a vague recollection of someone on PPWatt discussing a form where the reverb went in place of the trem channel (a big loss in my view) so I will go have a look there. This is a feasible build so it is worth pursuing even if some of our elder members disapproved of 18 watt with reverb.

Dd

[zaphod_phil]

Yeah, I'd love to see that if you find one. If you're just looking to add reverb to an 18 watter, the "single valve reverb" method works very well.

And once again I’ll say that adding reverb to a Marshall 18W is a desecration! There’s enough natural chime and shimmer in the amp already, and the combination of distortion plus reverb just results in a mess. Note that none of the great famous vintage Marshall amps had reverb, and no doubt, there were good reasons.

[Bieworm]

Yeah, I'd love to see that if you find one. If you're just looking to add reverb to an 18 watter, the "single valve reverb" method works very well.

And once again I’ll say that adding reverb to a Marshall 18W is a desecration! There’s enough natural chime and shimmer in the amp already, and the combination of distortion plus reverb just results in a mess. Note that none of the great famous vintage Marshall amps had reverb, and no doubt, there were good reasons.

ZP you should be proud about witnessing one day surfbands use Marshalls on stage!!! Listen to early mermen. They overdrive all the time..WITH reverb!! And it sounds awesome !!!

[JMPGuitars]

And once again I’ll say that adding reverb to a Marshall 18W is a desecration! There’s enough natural chime and shimmer in the amp already, and the combination of distortion plus reverb just results in a mess. Note that none of the great famous vintage Marshall amps had reverb, and no doubt, there were good reasons.

I know. Check this moron out: https://www.youtube.com/watch?v=HY-C290qE-4

That guy made an EF86 18 Watter in a combo - with reverb! And then played a jazz box through it?! What a mess.

[Bieworm]

And once again I’ll say that adding reverb to a Marshall 18W is a desecration! There’s enough natural chime and shimmer in the amp already, and the combination of distortion plus reverb just results in a mess. Note that none of the great famous vintage Marshall amps had reverb, and no doubt, there were good reasons.

I know. Check this moron out: https://www.youtube.com/watch?v=HY-C290qE-4

That guy made an EF86 18 Watter in a combo - with reverb! And then played a jazz box through it?! What a mess.

Wow!! That's an easter atmosphere!!! Who can spot the egg hidden in the video ?

[JMPGuitars]

Wow!! That's an easter atmosphere!!! Who can spot the egg hidden in the video ?

Well if you think that was bad, the dude made a version of ZP's Superlite TMB, but with EL34s and even more reverb! https://youtu.be/PeRZXThV54s?t=215