McGyver has nothing on me. Loads of amp work thread!

Pierre

Stratologist
Well my ol' Laney AOR30 needed some work... so I ordered some caps (16uf/475V to replace 15uf/450V) and a new speaker, an Emincence Cannabis Rex.

First things first... speaker. Open it up, try to put it in and... it doesn't fit! ARGH! Didn't know what to do. So I tried to find out why, and figured it out. And then I had the genius idea of attacking my amp with THIS:
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That ledge there was what was keeping the Emi out.
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On the picture I'd already sawn out most of it. I then used a file to smooth things out. Then in went the speaker.

Then I had to wire in 4 caps in. Here's the old board:
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Two days ago I'd also replaced the main filter cap, an old LCR 50uf+50uf by a JJ of equal specs.

And here it is now:
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Tada! Was dead easy. With the help of some TGP guys I managed without ANY issues. I simply undid all the pots from the chassis, desoldered the reverb tank terminals that were in the way, and lifted the PCB off one side. Then back in without a single issue.

After that I tightened the power tube sockets. I don't have any contact cleaner so I didn't do that, but next time I think, at least on the preamp valves.

Valves are a 12AT7 in V1, a TAD 7025 in V2, a quiet EH12AX7 in V3 and a JJECC83S in the PI. Dunno if I'll keep these in this order... we'll see. Two JJ6V6S in the power valve sockets.

Fired it up and... nothing wrong at all! Much more quiet, I have now a little more volume, the bass don't fart out when I crank up the input, and the gain channel is not very useable, fantastic crunch in fact! Very JCM800 alike, A LOT more than before. Takes the Plexitone and ACTone even better now too :D Which is awesome. I think now it's sounding just about as good as it could. I only have about 160 pounds in this amp by the way... not too shabby. It's VERY tough finding a balance between a clean sound and a nice OD by the way, as it doesn't have an OD channel, but more of a boost. You get three gain stages + another footswitchable... but it's actually even weirder.

You have preamp1, preamp2, preamp1 level, master volume. Gasp. Still not entirely sure of what is what... but anyway with this you can't really have a nice clean sound and a light OD. It's mostly very ligth crunch, cleanable with your volume pot, and very nice medium gain OD. Not so bad. It's still not a very loud amp though, but it's also got boosts on the EQ pots and a lot more gain on tap.
Also quite a bassy amp. I still have to keep the presence down some, but it's not as piercing and annoying as before. Just right in a way, in that I still have some room if I need more brightness!

Awesome stuff.
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Re: McGyver has nothing on me. Loads of amp work thread!

My sister has an aor 100 head and yeah, getting a balance between overdrive and clean with just the amps controls is very very difficult. Great sounding amp though! Great work bro! I use my plexitone prototype through her amp (well, technically she was using it) and that pedal *likes* that amp a lot! So does her MXR Distortion III though.
 
Re: McGyver has nothing on me. Loads of amp work thread!

Aye the PT likes Marshall preamps and power amp. Mine's 6V6 powered though so I believe the PT could sound even better. There are some settings where the PT sounds EXACTLY like my amp, it's scary!
 
Re: McGyver has nothing on me. Loads of amp work thread!

Nice job on the amp.

If you take your time, fixing/modding an amplifier isn't that difficult. I never used to even look at mine. Now I pretty much do all repairs and mods on all my amps.
 
Re: McGyver has nothing on me. Loads of amp work thread!

Cool! Glad you worked it all out and didn't screw anything up -- that'd be a serious bummer!
 
Re: McGyver has nothing on me. Loads of amp work thread!

How challenging exactly was it to mod your amp? Did you have to drain the caps? I want to do some basic mods (remove R6 and R7 100K resistors and replace with a single 470K. + replace VR-1 100K POT with a 1 MEG POT) to my AOR50 but I'll probably end up getting a tech to do it for me.
 
Re: McGyver has nothing on me. Loads of amp work thread!

It's mostly not very hard. I left my amp unplugged for a full day and the caps were empty... which is actually worrying in itself... So there may still be something off with it. But it sounds great and all works good so ah well...

My board doesn't have the R/C/D written on it... if yours doesn't, it'll make your life harder but it's not that hard at all to trade the PCB.
 
Re: McGyver has nothing on me. Loads of amp work thread!

depending on the top of amp, most newer ones (like the 5150 drain on their own), if its a tube rec, i believe you can take the rectifier tube out, turn it on and it should drain itself...

edit: at least that's what i heard on TGP
 
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Re: McGyver has nothing on me. Loads of amp work thread!

I left my amp unplugged for a full day and the caps were empty... which is actually worrying in itself... So there may still be something off with it.
Depends on the Cap Value and it's age.After 24 hrs ,i'd say most caps would be discharged.It's things like TV tubes that stay charged for days/weeks, and Microwave Caps.

Draining caps-Unplug at the power point and then turn the amp on!
 
Re: McGyver has nothing on me. Loads of amp work thread!

I originally reco'd this about ten years ago,for a guy who played in a band i mixed.He ended up with a Marshal head ,so i bought this from him.
I,ve been doing more reco-ing/upgrades.New H.V. caps new pre-amp valves and phase splitter.New valve sockets and a few new bits and pieces on the Circuit strip.
It's ongoing at the Mo!

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