New Amp Day - Kinda
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BigSteve22
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That is one spiffy looking little amp! Looks to be truly first class workmanship too, very pretty wiring! Anxiously awaiting the sound clips. :icon_thumright:
mayfly
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Gentlemen,
Been playing the amp a lot. Initially I was not a fan of the overdrive sound: very harsh and hard sounding. started just playing it clean/quiet (which was the intention anyway) and didn't give it a second thought...
... until I read somewhere that JJ 6V6s are not actually 6V6 construction. Rather, they are more like a de-rated 6L6. Hmmm. So I pulled it out and had a look:
Yea! It does look a little large doesn't it? and the plates look funny as well! Must be something to this.
As a guy who used to build/repair amps, I happened to have a small stash of tubes that I hadn't gotten rid of yet:
In there was this little beauty! That's right - Radio Shack!! You can tell that it's a true 6V6 type by the size and plate struture. Just look at it compared to that big JJ.
so I put it in and fired it up on the dim bulb. It didn't blow up and there was sound, so I warmed it up on full voltage and found a guitar. It sounded GREAT!! Oh man - it made a huge difference. I thought I had a winner, but it didn't last even all the way through a song when the volume started to drop off. Was still clear, just quieter, and quieter, until there was nothing. Figured an open in the heater. <sigh>. Oh well - I decided to pull the tube and search for another. Then it happened: the base separated from the bulb all in a creaky sounding pop!
ooops. Now that's pretty interesting!! Yea Radio Shack!!
ccasion14:
I pulled out one of my NOS mazda 6V6 (french military don't-cha-know) and put it in. Sounded better than the JJ, but didn't come close to that Realistic.
... to be continued...
Been playing the amp a lot. Initially I was not a fan of the overdrive sound: very harsh and hard sounding. started just playing it clean/quiet (which was the intention anyway) and didn't give it a second thought...
... until I read somewhere that JJ 6V6s are not actually 6V6 construction. Rather, they are more like a de-rated 6L6. Hmmm. So I pulled it out and had a look:
Yea! It does look a little large doesn't it? and the plates look funny as well! Must be something to this.
As a guy who used to build/repair amps, I happened to have a small stash of tubes that I hadn't gotten rid of yet:
In there was this little beauty! That's right - Radio Shack!! You can tell that it's a true 6V6 type by the size and plate struture. Just look at it compared to that big JJ.
so I put it in and fired it up on the dim bulb. It didn't blow up and there was sound, so I warmed it up on full voltage and found a guitar. It sounded GREAT!! Oh man - it made a huge difference. I thought I had a winner, but it didn't last even all the way through a song when the volume started to drop off. Was still clear, just quieter, and quieter, until there was nothing. Figured an open in the heater. <sigh>. Oh well - I decided to pull the tube and search for another. Then it happened: the base separated from the bulb all in a creaky sounding pop!
ooops. Now that's pretty interesting!! Yea Radio Shack!!
ccasion14:I pulled out one of my NOS mazda 6V6 (french military don't-cha-know) and put it in. Sounded better than the JJ, but didn't come close to that Realistic.
... to be continued...
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Cagey
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Seems kinda strange that a Radio Shack component would just slowly fail and ultimately fall apart shortly after you started using it. Never heard of that happening before. I think you should write them a strongly worded letter. Let them know that once they're done in bankruptcy court and have liquidated all their assets, that you're next. Demand satisfaction!
mayfly
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Yea. It's like that with different guitars as well. I think it's the amp. The Tone Depot instructions have some mods for reducing the amount of low end. I suspect that the original amp was just voiced with more bass to compensate for the small speaker. Or something...
BigSteve22
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Nice little amp. Hum? I didn't notice much, what with the fine playing and all! :icon_thumright:
stratamania
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Nice, just goes to show you don't need thousands worth of gear to get a tone.
mayfly
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folks,
After playing the amp for awhile, I decided that it has way too much bass for my taste. Yep Cagey it really likes the low E string!
Looking in the tube depot manual, there was actually a section in there saying "if you have too much bass, swap out these the two coupling caps". The caps in question are 0.022uf caps coupling the first preamp to the volume, and the second preamp to the outptut tube. The manual says reduce these to 0.01 or even 0.0047. Decided to give it a try.
Back off and tubes out:
Always have a little parts bin so that your parts don't roll off the bench and break / get under that 500lb furnace:
With the amp on the bench we can start working:
Now a lot of folks say "Arrrggg!!! a PCB amp!!! you can't work on those without taking the board out!" Well, actually if the amp uses any modern pcb you can. Since the last decade or so any PCP beyond bargan basement quality uses plated vias inside the holes. This makes a little 'rivet' in the hole which transfers heat really well. The upshot of this is that if you're a bit careful you can work on it from the top side with no trouble.
Here's the first leg of one cap out. Easy peasy:
Both caps are out:
and the board is ready for the new caps:
From my amp building days I've got a collection of Mallory 150s. Here they are. Old 0.022s are in the background:
Put them on the lead bender jig. This particular PCB is designed to accommodate different sized components which gave me some flexibility to choose the length of those leads.
New caps are in:
After playing the amp for awhile, I decided that it has way too much bass for my taste. Yep Cagey it really likes the low E string!
Looking in the tube depot manual, there was actually a section in there saying "if you have too much bass, swap out these the two coupling caps". The caps in question are 0.022uf caps coupling the first preamp to the volume, and the second preamp to the outptut tube. The manual says reduce these to 0.01 or even 0.0047. Decided to give it a try.
Back off and tubes out:
Always have a little parts bin so that your parts don't roll off the bench and break / get under that 500lb furnace:
With the amp on the bench we can start working:
Now a lot of folks say "Arrrggg!!! a PCB amp!!! you can't work on those without taking the board out!" Well, actually if the amp uses any modern pcb you can. Since the last decade or so any PCP beyond bargan basement quality uses plated vias inside the holes. This makes a little 'rivet' in the hole which transfers heat really well. The upshot of this is that if you're a bit careful you can work on it from the top side with no trouble.
Here's the first leg of one cap out. Easy peasy:
Both caps are out:
and the board is ready for the new caps:
From my amp building days I've got a collection of Mallory 150s. Here they are. Old 0.022s are in the background:
Put them on the lead bender jig. This particular PCB is designed to accommodate different sized components which gave me some flexibility to choose the length of those leads.
New caps are in:
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Cagey
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I'm sure you'll have a sound demo coming up here shortly, but after listening to the first demo again, I'm wondering if what we were hearing was "too much bass" or the speaker's resonant frequency. The reason I wonder is overall, it sounded pretty rounded. It was only when you hit that low E that I could feel it in my bones. I'll be curious to hear what the mod does. Hopefully, that'll fix it, since replacing the speaker will just add to your storage space requirements for "parts that I'll never use, but are too good to throw away" :laughing7:
