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Topics - Stompin_Tom

#1
Amplifier Discussion / Amp kits...
September 06, 2006, 11:23:30 AM
This kit might be useful for a practice amp.

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=320-214

This one's got a bit more power (I assume it would be easy to convert to run in parallel):

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=320-212

And finally, a guitar preamp kit. I wish there were more details about this one. I'm curious, but doubt that it would sound that great. Seems a bit pricey, too:

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=320-134
#2
Sorry if someone's already pointed this out, but I just saw it. The current isn't too low/voltage too high, is it?

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=129-035
#3
Amplifier Discussion / Gibson LabSeries L5 (pics)
August 18, 2006, 12:58:48 PM
Hello... I took some pics of my L5 chasis in the crappy head I built (it didn't come with the original cab--got it cheap!). First one is right before I took it apart:



This one is the guts:



You can see the power supply (the transformer is mounted on the bottom of the chasis at the bottom of the pic), the power amp (upper right of pic), and the preamp is all behind the pots... you can't see them in this pic. You can read a little about it and see the schemo here: http://www.netads.com/~meo/Guitar/Amps/Lab/schem.html

Now that I've got you looking at this post, here's my problem. I've been using this thing for about a year now with no problems what-so-ever... but, about two weeks ago I was recording and it was cutting in and out... not exactly cutting out, but getting much quieter then louder again... I thought it was a pedal problem, so I took all pedals out of the loop and it worked fine for the rest of the night. So, two days ago I'm recording again and it starts cutting out again... I try every combination of equipment in the practice space and it has to be the amp... that's why I took it apart, but I couldn't find a loose connection or bad solder joint. A friend suggested that it might be overheating or that the power in the room is dipping too much... both seem unlikely to me because I've been using is for so long with no problem... If the electrolytic caps were failing (this things pretty old) what would that sound like? Do these seem like symptoms of anything you're familiar with? Ideas on fixing? Thanks!
#4
Preamps and Effects / Powering your preamps
August 17, 2006, 04:58:08 PM
I'm curious... how have others here who've made their own amps powered their preamps... I'm thinking of a 3886 chipamp and I'm considering my options for preamp, transformer, etc... separate transformer, or one with extra secondaries...etc.
#5
Amplifier Discussion / Stereo to mono power amp
August 16, 2006, 06:00:17 PM
As I mentioned in another post, I'm planning to make a stereo guitar amp from the chipamp.com lm3886 kit. I'd like to have the option of going from stereo to mono if I'm using someone elses (mono) speaker cab at a gig, or if I decide to go with one preamp instead of two, etc. Can I simply install two switches? One at the input that would split one input into the two amps boards... and one at the output to combine the two outputs from the amp boards into one speaker out... bridging the two amps in parallel, right? Is there any problem with this? some sort of oscillation or overload or something?
#6
Sorry about this everyone... I'm just knew to this world of ac. I'm (still) planning on putting together a stereo guitar amp based on the stereo lm3886 kit from chipamp (not the dual mono, but with one power supply). I'm hoping to get this kit for my b-day in a week and I'm planning ahead for what I'll have to buy. So, I'm looking at this transformer that RDV recommended:

http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=122-615

RG said this would be good to power two lm3886, which is what I want to do... but, now here's where the stupid question comes in, it has 22v + 22v secondaries... does that mean it has four secondaries of two pairs of 22v (each pair with a + and a -)? ...and ground. If I understand the schemo from the kit that's what I'd need, correct?

Also, unrelated question, if I'm planning to push 8ohm speakers I'd probably want something closer to 35v to get 50watts output, correct? Got that idea from the datasheet (http://www.national.com/pf/LM/LM3886.html).