Here's a question for ya!

[diode breath]

I have a Trace Elliot Velocette Twin amp -- two, 15-watt Class A outputs, 1-10" speaker per amp. Mono preamp, voiced kinda like a Vox. It has a built-in effects loop with a mono out, and either stereo or mono return.

What I would like to do is find a good stereo chorus that works with line-level signals, so I can plug in external cabinets and sweep the chorus side-to-side. Does anyone know of a line-level chorus? Alternatively, is there a device available that will attenuate a line-level signal output from the amp to guitar-level for processing by a stomp box, then return it to line-level to return to the amp? Yet another option is building the buffer device, but my design chops are SEVERELY deficient when it comes to solid-state stuff....

Any help would be greatly appreciated.

Thanks,
MJS

[Steve Conner]

Surely a guitar amp effects loop should already have a suitable level for using stompboxes in it? I thought that was the whole point of the effects loop. Not every guitarist wants to lug a rack of pro effects, and hot pickups aren't really that much below line level either.

It may have send and return level controls that you can adjust.

[diode breath]

Thanks for your response, Steve.

I thought the whole idea of line-level loops was to maximize the signal-to-noise ratio in order to keep the transistor noise from being too distracting. I re-checked the amp, and it does not have send-return levels. I was wondrin' if anyone made a line-to-guitar buffer that will work both ways. Obviously, it would have to work line-to-guitar in mono to the chorus, and guitar-to-line in stereo back to the loop return.

If that's not viable, suggestions for a good line-level stereo chorus only device would give the effect I wanted. I really don't want to use one of those multi-function rack-mount devices that were so popular in the past.

Ideas are appreciated, or a schematic to build a buffer.
dB

[Steve Conner]

Well, according to the instruction manual for your amp:

http://www.britishaudioservice.com/inst/VELTW.PDF (page 5)

"The SEND is for connection to the input of effects units and can drive floor type battery powered effects pedals or 19” rack type studio effects units."

What's more, on page 7, it says that the nominal operating level of the effects loop is -20dBu, which is quite low, so should be fine for stomp boxes. Like I said, I'd be very surprised if any amp maker used an effects loop with a level unsuitable for stompboxes. It's missing the point of the effects loop.

So I'd just give it a go with a chorus stomp box. I like the blue Boss one.

[diode breath]

Thanks, Steve. I appreciate your input. I'll try it when I decide which chorus I want to use. Probably just take the amp along to see what it sounds like in the store. I live so far out in the boonies that driving back and forth to a store is a bit of a drag.

[Mark Hammer]

The Line 6 Tone Core Space Chorus has stereo in and out, and does a decent emulation of the old Dimension C pedal, one of the best choruses ever.

Alternatively, do consider that making the stereo field richer does not require altering both channels, merely one of them. The old Roland Jazz Chorus amp worked like that, and a nifty litle fender SK-20 Chorus amp I picked up recently works that way too. One channel is dry and the other is variable wet.

Having dickered with my little SK20 a bit, I can also attest that:
a) a short slapback with an all-wet feed to the second channel is very nice, and
b) a phaser feed to the second channel (similarly all-wet, although wet+dry works too) is also nice.
c) an auto-pan pedal is cool for dual channels (the Line 6 Tap Tremolo does stereo auto-pan)

Actually, all those Tonecore pedals with the stereo docks sound amazing when you use both outputs. The Liqui-Flange and Roto-Machine sound "nice" in mono, but when you have a stereo spread on a Leslie sim you get much more of the swirl magic. The stereo sweep of the Liqui-Flange when it does thru-zero flanging is VERY nice.

[diode breath]

Thank you, Mark -- I'll keep thiose units in mind. I wanted to use two, Marshall 1965 4-10 cabinets, one for each side of the amp and try to separate them by about six feet to see if I can get that swirl.

[oc disorder]

this may help

[Mark Hammer]

The schematic provides useful information.

Note R34/R1 just before the send jack. That 120k/10k pair drastically attenuates the output signal, meaning that it has been "prepared" for regular stompbox levels. Conversely, R41/R40 and R42/R44 provide a gain of just under x5 for the returning signal, suggesting that they are anticipating stompbox output levels and giving them a little nudge.

So, the amp is safe for patching stompboxes into the loop. HOWEVER, you would need to set up a special cable for yourself or perhaps a little junction box to permit use of "standard" cable if you were only going to run one output to a pedal and feed it uniquely to one side.

This amp is much like the little Fender I bought where everything up to the send is mono, and the return can go to both amps in common if nothing is patched in, or else you can have one amp side different from the other if something is patched in.

[diode breath]

I would like to thank both OC and Mark, and Steve, very much for their inputs. I have to go to the Bay Area for a few days, but I'll be draggin' the Velocette around to Ray Hennig's and Musicmaker's here in Austin, auditioning choruses (chori?)

Thanks again, all of ya!
dB