Adding an onboard tube driven reverb to a Marshall 1974 18 watt clone?

[olddawg]

I've picked up an El84 chassis and intend on building a 18 watt clone. This may have been discussed before so I appologize in advance if it has been covered. It did not turn up in my search. I would like to incorperate an onboard reverb in my clone in the normal channel. Does anyone have a schematic for this or can point me in the right direction? I've collected several schematics from various sources. Most involve removing the trem and adding aTMB tone stack or increase gain mods along with the stock clones. It seems that an onboard reverb would be a big improvement. Any comments would be appreciated.

[Bruce / Mission Amps]

Buy a $110.00, Line 6 ToneCore Verbzilla and forget about modding the amp.
Plug and play your little heart out.

http://www.zzounds.com/item--LINMS9

[olddawg]

Buy a $110.00, Line 6 ToneCore Verbzilla and forget about modding the amp.
Plug and play your little heart out.

http://www.zzounds.com/item--LINMS9

Yeah, or a Holy Grail, or a Holier Grail, or whatever. Right now I'm using $30 stereo Behringer DR100. I've never really liked how any of these sound on my input pedal chain. I'm going to check out a Vox Berkley schematic.

[Chuck H]

The good news is that an onboard reverb will sound better than a pedal or processor. The bad news is not by very much at all. The reason is that all of an 18 watt type amps distortion is being generated in the PI and power tubes. The preamp is clean all the way to the input of the PI. So if the reverb signal is placed at the front of the preamp or at the end of it (as it would be with an onboard type) it's still gonna get creamed by all the same distortion generating gain stages. I have had limited success with reverbs in amps with this characteristic. I find that if you run a reverb and a delay pedal that you can turn the reverb down for more clarity and reinforce the reverberated quality of the tone with the delay pedal and get better results than with just the reverb turned up louder.

I know this isn't much help. But to get get good natural reverb with distorted tones you need to reverberate the distorted signal. Distorting the reverberated signal always sounds bad.

I did have a good idea for a slave amp that I was going to call the "Juice Box" which is just an 18 watt slave amp (PI and power tubes) but with a built in reverb. Then you could run a line out from your 18 watt to the "Juice Box" with an effects processor or anything else in between to get more proper sounding effects or even a tube reverb with your 18 watt tone.

It's along the lines of something I've done before by using the line out on one of my amps to run a Quadreverb into the P.A. So my "tone" came from my amp but all my effects came from the P.A. speakers. Not a good arrangement for everything, but an 18 watt slave amp would fix that.

Chuck

[Tubenit]

18w w/reverb

You will need ExpressSCH (a free download) to open some of these files.

I've heard this one in person and it sounded great:
http://www.el34world.com/Forum/index.php?topic=560.0

This is a DRAFT of an idea that a builder is currently working on:
http://www.el34world.com/Forum/index.php?topic=5530.0

And on the 18watt forum another one:
http://18watt.com/storage/18watt-reverb.gif

However, I probably would install a passive effects loop prior to the phase invertor and run a delay or reverb thru it as Bruce suggested.

With respect, Tubenit

[Bruce / Mission Amps]

Are you trying to get a good room ambiance sound with the added reverb in the cleaner modes or are you trying to get a over driven distortion amp to have room sounding reverb?
If you are like most players, you probably want some reverb for the cleaner settings with just a little hair on the tone and a good sounding reverb pedal works great for that.
High gain distortion amps with even a tiny bit of too much reverb sound muddy as hell to me.

[olddawg]

Are you trying to get a good room ambiance sound with the added reverb in the cleaner modes or are you trying to get a over driven distortion amp to have room sounding reverb?
If you are like most players, you probably want some reverb for the cleaner settings with just a little hair on the tone and a good sounding reverb pedal works great for that.
High gain distortion amps with even a tiny bit of too much reverb sound muddy as hell to me.

I'm just trying to build a more versatile small amp. I agree that massive amounts of reverb doesn't work well in a high gain application. Maybe a line out with an EQable rack might work better for a one trick pony. It would be nice to have an onboard spring reverb available on the trem channel and maybe a slight blend available on the gain channel. I'm still thinking on how to set it up.

[Chuck H]

I'm still thinking on how to set it up.

FWIW El84's require so little drive voltage compared to other tubes that it's eminently possible to inject the reverb on the cathode coupled side of the PI and still have enough drive to run the PA into the bricks. Most 18 watt PI's use a 47k tail so the 100k/82k plate loads for balancing make little difference at that point. Go with 100k/100k and skip the .1uf bypass cap on the cathode coupled side of the PI. Then inject the reverb there. That way you skip at least one stage of distortion on the reverb signal.

Chuck

OOooh. Just saw that the 18 watt already uses the cathode coupled side of the PI as the 2nd channel input. But if your clone is like many your only using one channel. So there is nothing to lose by injecting the reverb there. The "dry" signal will remain unchanged. Does your clone have a 2nd channel?

[Tubenit]

18w reverb

Are you referring to something like this?

With respect, Tubenit

[Chuck H]

Yup.

[daz]

I'm telling ya, the absolute best way to add reverb is via a DI speaker out to a good effects box and into a second small amp. It has every advantage in the world including not fouling up your dry signal. and the second am need be nothing big or special. I use a tiny little peavey that i think is 10 watts with a 6" speaker !!! Because the wet sound of a fairly well drenched reverb tone only has to be about 25% as loud as the main amp. A little 20 watt SS amp with a 10" would be more than enough for any bar gig. And because the DI is a complete output that includes power amp distotion, as long as you set the effects amp totally clean it will do as good a job reproducing the main amp's sound with reverb as you'll ever need. A second 10-15 Lb amp thats tiny is no problem to carry along either. Another bonus.....stereo sound of a sort. Oh, and the ability to change the verb any way you like via the processor or by trying a different box, plus you can use other effects too as long as they are the type that can be 100% wet. I mean, the advantages are endless. Try it...you'll never go back. I tried it 15 years or so ago and haven't gone back !

[Chuck H]

+1

It's along the same line as my earlier post.

[Bruce / Mission Amps]

Interesting.... on stage, one of my customers uses a very cheap VOX SS 15 watt Pathfinder sitting on a stool as his "second", effects driven amp.... that actually sounds really good live and adds a second voice to the stage sound.

One of these things:
http://cgi.ebay.com/Vox-Pathfinder-V...3%3A1|294%3A50

[GibsonLover]

stereo amp

A lot of folks do something similar, either a second amp or a second channel. It the very reason I built a stereo head. Mono pre, normalled thru two returns to two SE 6L6 outputs. The 'straight' side keeps all the guitar dynamics and the other side adds ambience, all is a 2x12 and stereo head configuration. Larry Carlton and God knows who else do the same thing live, taken directly from studio recording applications (never print the reverb...).

[Chuck H]

Bruce...Build the Juice Box. Slave power amp with a reverb in a 5e3 size package. I know it may seem expensive for what it is. But it would be useful as hell.

Chuck