FET Simulation Suggestion: Lab Series L5?

Paul Marossy · September 16, 2006, 10:40:16 PM

Ty Tabor used a Lab Series L5 on the first few King's X albums. It's got a killer crunch tone. Anyone else interested? I've got the schematics for the amp BTW.

KerryF · September 16, 2006, 10:44:44 PM

I am very interested! I guess you can post, or PM it to me if you feel like it

. Thanks

Paul Marossy · September 16, 2006, 10:50:45 PM

I don't want to design it, I'm just fishing to see if anyone would be interested in taking a stab at it. I just don't have the time to attempt it...

KerryF · September 16, 2006, 11:04:12 PM

Well you said you have the schematic, so I would like it

Paul Marossy · September 16, 2006, 11:06:38 PM

Oh, duh.

You can find the schematic at the bottom of this page: http://www.diyguitarist.com/GuitarAmps/LabSeriesL5.htm

KerryF · September 16, 2006, 11:11:31 PM

haha nice!

wow I thought that I may take a shot at making a preamp pedal for it... that was until I saw the schematic

!!! Insane! I guess I wont be building that for a while...

EDIT:
I was just looking through Schematic Heaven just to check out a bunch of amp schematics for future reference, and I came across the schematic for this again. http://www.schematicheaven.com/newamps/moog_labseries_l5.pdf

Paul Marossy · September 17, 2006, 09:08:50 AM

Yeah, it's not a simple slam dunk, but I think it's comparable to the Dr. Boogey. Maybe a little more complicated?

KerryF · September 17, 2006, 09:17:55 AM

Yea definately. But I have a question for you thats off topic:

On you website (which I love

) you say you have preamps in your guitars. Well I have a Godin guitar which was pretty much put out of use after I bought my PRS Custom 24 Ten-Top 20th Ann. Well, I was thinking that maybe I could do some small stuff to it to make it a bit better. So your FET preamps, what is the point to them? Would have to do any drilling to the guitar?

brett · September 17, 2006, 09:34:38 AM

Hi
Interesting pre-amp. It's a pity that the compressor and distortion controls are based on the hard-to-get 3080 and 3094.

Also, I wonder how they get away with an input stage consisting of a 4558 with a 4.7M feedback resistor?
That ought to hiss worse than an angry cobra.

cheers

Paul Marossy · September 17, 2006, 09:57:25 AM

QuoteSo your FET preamps, what is the point to them? Would have to do any drilling to the guitar?

They boost the signal a little bit and make up for cable losses. In effect, it's similar to making your guitar have EMG type pickups in it. No drilling required unless you want to be able to bypass the preamp. In one of my guitars, I have one installed with a bypass switch and a 4.7uF bypass cap on the source of the FET, and it gives a helluva boost when I switch it in. Too much, actually. Anyhow, that's the point behind the preamp.

lovekraft0 · September 17, 2006, 10:56:16 AM

What is it you want to "simulate"? The patented Multi-Filter section would be easy enough to implement with a hex inverter chip and a dual opamp, if that's the part you're after - that might make an interesting pedal. The rest of the circuit looks like a pretty standard late 70s SS preamp with Bax tone controls, except for the OTA compression/distortion section, which might also be worth updating with a LM13600/700, if that's the sound you're looking for. Modernizing the whole preamp with better parts seems like a pretty epic task, but should be possible (given the necessary skills - I wouldn't attempt it, but there are plenty around here for whom it wouldn't be particularly challenging).

I personally never really liked the sound of this amp, although as you mentioned, Ty used it well enough, but then I didn't care much for any of the Moog/Norlin collaborations (the RD series active axes in particular stand out in my memory as being fairly wretched).

Paul Marossy · September 17, 2006, 02:41:14 PM

QuoteWhat is it you want to "simulate"?

The sound! I don't know if it's possible, but I think that Ty's tone on those early King's X albums is killer. Super heavy crunch I guess you could call it. I suppose this is a little too complicated for an FET simu circuit, huh?

JHS · September 17, 2006, 03:00:53 PM

If you like the L5 buy one used or build the L5 preamp and connect it to a good tube poweramp or via the poweramp in a good guitar amp.

JHS

Paul Marossy · September 17, 2006, 03:02:36 PM

QuoteIf you like the L5 buy one used or build the L5 preamp and connect it to a good tube poweramp or via the poweramp in a good guitar amp.

Yeah, but I would like to get that sound in a stompbox.

JHS · September 17, 2006, 05:46:08 PM

Me too. I checked a L5 years ago in a music store, great clean sound for a solid state amp but the amp's distortion sound was not that good, not very convincing. BB use the clean sound most of the time and Ty may had used a good distortion or overdrive box in front of it.
I'm not shure if the amp can deliver Ty's sound w/o a good FX-pedal.

JHS

Paul Marossy · September 17, 2006, 07:11:39 PM

QuoteI'm not shure if the amp can deliver Ty's sound w/o a good FX-pedal.

I think it can. My friend's L5 can get that sound just by plugging the guitar straight into the amp. I guess he knows how to tweak the knobs. And maybe the guitar that you use makes some difference, too (pickups that is)...

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FET Simulation Suggestion: Lab Series L5?

lovekraft0