Laney AOR lead 50

[axpro]

Hey guys,

Got a Laney AOR lead 50 for a good price. it is the 8 knob version with the switch for output ohmage.

Tried it out and it is loud-ish, but kinda crap at the moment... It had some old mostly "leftover" generic tubes. Put in some new ax7's and a pair of Mullard Reissue GT el34's

BUT i didn't get to power it up before i left work.

The whole volume control switching arrangement is annoying at best, and horrific at worst. I konw it is supposed to be an 800 clone with more gain, but there are some HORRIBLE sounds coming from this thing! GAH!

THough that big Iron and roomy chassis have me thinking impure thoughts...

We'll see. I'll try it tomorrow withthe new tubes and see if that makes a difference... if not, I'm cracking her open!

[Gtr_tech]

I've gone thru a couple of those 8 knobbers. I thought they sounded like ultra bright ass stock. They have potential tho...if you have the chops to redesign them.

[axpro]

I haven't opened it up yet. put in some new tubes and it is 10%better, but a pile of crap with a sign adverstising "now 10% better!" isn't going to get a lot of sales
:P

I'll look at the amp and see if a previous owner did some crazy mods or anything. I may do the "lazy guy" thing and just order a reissue JCM800 turret board set from Metro amps and put that circuit in there. I can add a switchable something or other and a resonance control to use up the space.

That or maybe a ThunderTweak dual bias design.

Either way, i don't think it is staying stock!

[Gtr_tech]

The replacement board might not be a bad idea. That way you can tidy up the wiring while yer in there. Try a hotter 2nd stage too.....use a 2.7k bypassed with a .
68. If thats too bright use a .001 to gnd after the 3rd stage.

[gldtp99]

I pulled the orig PCB from my AOR 50 (same version as yours, i believe) and built a turretboard version of a hi-gain Krankenstein lead channel into it---i did the Resonance and Sweep (adjustable slope resistor in tonestack) controls and it sounded very much like the Krankenstein head that belongs to a friend---i also re-did the power supply filtering values and added a tube buffered effects loop.
After playing it for a time i realized that, while it was an interesting experiment, that type of hi-gain tone is too much for me----so i de-gained the circuit---- changed Rk values and converted from plate to cathode driven tonestack---it's closer to what i'd consider useful but still not my idea of ideal tone response, but some really like it as it is---i'll decide how to proceed later when i get more time to deal with this project.
But my point really is: these AOR 50's are a great platform to rebuild/mod if the orig tone doesn't exactly floor you---- get a Metro, or other, turretboard and go to work--- the possibilities are almost endless-...............gldtp99

[axpro]

Krankenstein eh?

I am not a fan of the original, like you said TOO MUCH gain! I tried the revolution model when krank first came out and was much more impressed with that.

I dunno, i find the AOR head really finicky to control, and not "good" sounding at all. It's very complex with all the knob interaction... I never had that much issue with Mesa Boogies, or TSL series marshalls, or anything else, bu this JCM800 type is just finicky as all hell. I think getting rid of the 4 volume/gain controls and replacing with a nice since gain and master volume would make a world of difference.

I am leanign towards a 2204. but don't know what i am doing with the extra gain stage as of yet. either i will run the first 2 stages as parallel triodes to see how it sounds, or i'll leave it open for future changes.

I'll know in a bit. the amp is at work, and i head in in 15 minutes!

[axpro]

I looked at it. cleanly wired, no mods, other than what looks like a small repair of a burned resistor. I thought for about 2 seconds that i might re-use the board, but decided against it. 2204 turret board on the way from Metro. new pots as well.

ONly thing to decide is what to do with the extra 12ax7. I don't use much for effects, so that is out. I don't think i want to deal with verb (too much hassle) A bias modulatiing trem???? not really for a Marshall....

I think it will either be an extra gain stage (maybe in parallel) or i will run the first 2 gain stages in parallel. ... anyone try that yet?

[axpro]

Update!


I went with the Board from Metro (They make VERY nice stuff, quite glad i went with that)

a few changes, and a little low on the B+.

Tweaked what i could, ran shielded from input to tone controls.

Tried the first 2 stages in parallel, but it was a little too much (of course that was BEFORE i figured out some issues and ran so much shielded cable)

Ended up changing the bypass on v1a to 2.2/1uf and v1b is a seperate tube, in parallel. Also cut out the 470 pf treble peaking resistors. Now it is a heavier than stock, very "Meaty" JCM800. There is a little parasitic oscillation to track down, as sometimes with higher gain, my sustain craps out. which i think is turning out to be parasitic Osc... I'll have to mess with the lead dress some more i think. But it is pretty good!

[axpro]

Update Update!!!!!

So,

Redid some of the lead dress, cleaned up wiring a touch more, and it is quieter than ever! (I wish my princeton clone was this quiet! )

The suspected parasitic oscilation seems to be gone as well, since my sustained notes don't drop out of existence anymore.

I am personally not thinking the parallel stage is doing all that much, so I may change it back to two non parallel stages and remove the extra tube. that might Bump the overall B+ a little bit. Unfortuantely that will have to wait, as i was kicked off my temporary workbench (dining room table) cause the missus wants to eat "dinner" or some such nonsense!

[Gtr_tech]

Removing gain stages won't affect the b+ at all. We're talking really small currents here.

[axpro]

Even if removing the parallel stage means i am running one less 12ax7?

I figured it would bump it up a touch...

[Gtr_tech]

Won't make a lick-a difference to the b+ supply. You'd gain a little headroom in the heater current department tho.

Where is your b+ at now? The last couple AOR heads I had in ran pretty low supply voltage.....around 380-390 IIRC once the output section was biased up. I don't care for low b+ myself....things tend to get mushy fast. I'm more of a 480-500-ish kinda guy with 34s and like fairly stiff plate and screen supplies.

[axpro]

Hey Tech,

Dang, i was hoping to gain a lil B+....

CUrrently, biased up it's about 420. Not starving, but it is a little mushier than i would like overall.

I am still optimizing lead dress, sustained notes at lower volumes sometimes die out (like they are choking out) so there are noise/crosstalk issues somewhere, but the effect is pretty minor.