LabSeries L2 (MN 315A) Schematic Request

[Bob3of3]

Does anyone have a copy of the LabSeries2 Schematics? I have one which covers the following models which are closely related but an exact schematic would be appreciated if anyone can offer it. This amp belonged to my late brother, a bass player, and I'm sprucing it up such that it may be enjoyed for many more years. The closest schematic I've found is for the L5(308A), L7(309A), L9(312A), L11(313A) with a document version code on the lower right of 993-042349-001. As near as I can determine, the LabSeries were a late 1970s collaboration of the Norlin companies Gibson and Moog, possibly made by Garnet, that the L2 is second generation amp. In my case, this header is generally functional with the user reporting a possible intermittant failure, but its working well after a good bath in isopropyl alcohol. A fan was installed in a circular side vent hole of the same size but from the pictures I've seen that was merely covered with fabric, so I'm not sure if the fan was an OEM kit or someone trying to cool a very dirty amp that simply needed a bath. Any copies of the L2 schematic or additional onfo much appreciated folks!

[g1]

Here: https://music-electronics-forum.com/...tics#post42349

[oc disorder]

I just noticed that the second link by VintageKiki that g1 referred to has a missing period or as we say downunder full stop .. before "jpg" which prevents access to the second schematic .
Should be http://www.braught.com/Schematics/L2b.jpg

[J M Fahey]

Killer Bass amp.
Just drive 2 EVM15 in a proper sized cab and get ready to crack walls.

[teemuk]

AFAIK, Lab Series L2, L3, L4, L5, L7, L9, L11 and K5 were made by Moog and had huge influence from Dan Pearce, one of the designers later founder of Pearce amps.

L2 and L4 were the bass amps. Both were heads and L4 was the most feature packed of them with two channels. They were largely based on design of the guitar amps L5, L7, L9 and L11 but didn't have the (non user adjustable) OTA distortion circuit.

The guitar amps all were about similar, using same circuitry and boards, except for different speaker configurations and rated output power. L11 was a head unit, most powerful of the bunch, rest were combos. L5 was the cheapest unit of the bunch. L3, the smallest and cheapest combo amp, was a Moog design as well but a very different kind than the rest, using overdriven MOSFETs and CMOS inverters for distortion. Obviously not much "Pearce influence" in it but nice design in its own regard.

I have no clue of K5, other than photo references.

...and some of these amps, head versions at least, were fan cooled, and had that circular vent in the side of the cabinet for the fan. It blows directly to heatsink that way.

Second generation, AFAIK, were relabeled Garnet solid-state amps. (Garnet was formerly the Canadian importer). Very different and much cheaper quality. You can see a glimbse of one in the Back To The Future movie, in the beginning where the band plays in School.