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Messages - Stompin_Tom

#31
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
#32
Amplifier Discussion / Re: Gibson LabSeries L5 (pics)
August 24, 2006, 01:29:55 PM
Thanks. It's at the space right now. I'll bring it home tonight and go over all the solder joints and check out the resistor values before installing the fan I just got. I hope nothing too serious has blown up in there. A bad joint or a slowly failing component would explain why it doesn't always cut out...
#33
Amplifier Discussion / Re: Heatsinks for your poweramp
August 23, 2006, 03:22:06 PM
uh... I was looking at this guy's site (he sells kits and completed amps) and his heatsink is pretty small (about half way down the page):

http://www.audiosector.com/chassis_integrated.shtml

Is there something special about copper that you could use a chunk like that instead of the standard heatsinks like Joe used? AND what *possible* effect could the heatsink have on the audio performance of the amp!?!?!?
#34
Preamps and Effects / Re: Powering your preamps
August 23, 2006, 02:39:21 PM
No one? I'm just curious... looking for ideas... transformers (scavenged/bought)... powersupply ideas, etc.
#35
Amplifier Discussion / Re: Stereo to mono power amp
August 23, 2006, 01:11:08 PM
What do you think of this kit.... much like what you're planning, RDV... I think...

http://www.audiosector.com/lm4780.shtml
#36
Amplifier Discussion / Re: Gibson LabSeries L5 (pics)
August 21, 2006, 11:39:57 AM
I see. That makes sense... I'll take a closer look at the schematic.
#37
Preamps and Effects / Re: Pictures
August 21, 2006, 11:03:11 AM
yeah, looking good, syndromet. Not sure what the sonic destroyer is, but it look brutal...
#38
Amplifier Discussion / Re: Gibson LabSeries L5 (pics)
August 21, 2006, 11:00:25 AM
So I recorded with it again, and then practiced afterwards... It was on for several hours without ever cutting out. Strange. But the heatsink was very hot afterwards. I'd never noticed how hot it got before. I think I'll drop a fan into the head somewhere. Below the heatsink? Old computer fans run at half voltage work ok, right? Have to get a little transformer of some sort, too...

An additional advantage is that I've heard you can drive a 4ohm load with one of these if it has a fan to cool it. In fact, I'm pretty sure the '200 watt' L11 head they offered is just the same design, plus a fan and a 4 ohm cab... thus getting twice the wattage out of the same design. Not that I need it any louder, but just in case I have to use a 4 ohm cab at a gig...

Thanks for the help teemuk.
#39
Amplifier Discussion / Re: Stereo to mono power amp
August 21, 2006, 10:51:29 AM
Quote from: RDV on August 19, 2006, 05:14:13 AM
I've got everything I need but time and energy.

Yes, sir. I know how you feel.

I think I'll go with a big heatsink and a fan to be sure...
#40
Preamps and Effects / Re: Hiwatt-based preamp
August 18, 2006, 02:41:07 PM
My friend likes to use his with hardly any eqing (more or less flat) and that sounds much like your clips... I personally like Hiwatts set up to be really bright and cutting with my tele. It's hard to say if your pedal could do that from the sound clips. I think your pedal sounds good, even if it's not *exactly* like a hiwatt... and that's probably all that matters.

One thing I had thought of is bridging the norm and brill inputs with separate volume controls (instead of a switch between the two). Using both 'channels' at the same time on a hiwatt sounds really excellent. I'm not sure if that would have much effect on your pedal, though, as it wouldn't really drive the 'tubes' in the same way... but I'm curious.
#41
Amplifier Discussion / Re: Gibson LabSeries L5 (pics)
August 18, 2006, 02:26:11 PM
I don't actually use the compressor... it does seem to work fine when I've tried it, though.

I just read a review on Harmony Central where the guy says that some of the earlier models had to have their rectifier diodes replaced... He didn't say why and it's just a harmony central review, so I'm not sure what to make of this. Maybe if the power isn't rectified properly it could cause weird volume drops? Do diodes go bad with time and use?

Here's the power supply, by the way:

#42
Amplifier Discussion / Re: Gibson LabSeries L5 (pics)
August 18, 2006, 01:09:28 PM
Ok.. pic of preamp, too:

#43
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!
#44
Amplifier Discussion / Re: Stereo to mono power amp
August 18, 2006, 11:40:33 AM
I see. I looked at the data sheet and it looked comparable to two 3886s, that's why I asked.
#45
Amplifier Discussion / Re: Stereo to mono power amp
August 18, 2006, 11:25:46 AM
RDV, is there an advantage to the 4780?

Have you run into any problems running in parallel? You mentioned overheating...