After I'd gotten the dodgy tube socket thing sorted out, I started looking around for a DIN plug foot switch and didn't find one but I did find out something rather interesting.
The footswitch controls the reverb and the "automix" feature and thereby hangs a tale.
There are two channels, the bright and the normal. The bright has one input and the normal channel has two. In addition there is the automix jack. What I found out was that the automix feature uses one preamp channel to overdrive the other. Not my cup of tea, thanks,
But what I did find is that you can jumper the channels and get a lot more chunky clean tone than you can get out of either channel. It's a simple matter of running a jumper cable between input two of the normal channel and the single bright channel input.
Then, you can plug your guitar into the number one input of the normal channel and be happy.
A simple on-off foot switch may be just the thing to turn the reverb on and off, too.
UPDATE: I located an earlier Artist 240 which is the earlier version and...yep...I bought it, only this one has a 15" JBL. For a mere $200 which is nearly what the speaker's worth if it survives the trip.
Folks, these amps are the greatest thing since sliced bread and one hell of a bargain.
Should be here later this week. Film at 11 as they say.
Tuesday, September 12, 2017
Friday, September 8, 2017
Peavey Artist Gut Shots
Monday, September 4, 2017
Installing a Bias Control On A Peavey Artist
I got the commission to freshen up an oldish Peavey Artist circa 1980 or thereabouts. This is a single channel very basic amp with a solid state front end, reverb and a master volume, pumping out 100w or thereabouts into a single 12 inch speaker.
The idea sounds so good that I went and acquired one from Music Go Round and it should be here tomorrow if UPS doesn't ruin it.
Overall it's a nice idea well executed. The preamp integrated circuits are all socketed for easy changeouts and it's modular with a preamp board, a power supply board and a tube board. It was built with all Nichicon electrolytics-good material for durability and initial quality. The traces are easy to manage and it doesn't have any of that confounded no lead solder mucking everything up.
The only thing I don't like much is the fact that the power tube sockets are riveted to the chassis and soldered through the tube board. It could be an issue if a tube socket ever had to be changed.
These are the amps that Hartley Peavey made his fortune on, and it's a shame that Peavey has lost their way and become just another importer of Chinese made stuff of indifferent quality. You may have read my earlier missive on the Peavey Valve King 100 and what a steaming pile of crap it is.
With rare exceptions that is what Peavey became. I understand that the 5150 and 6505 heads are liked by fans of heavy metal but that's about where it stops. I've had my eye out for an early Peavey Vintage for some time but not a one has surfaced-that's the all tube 100w Fender Bassman with reverb-what a great idea.
I am of the opinion that at some point people will recognize that there is a lot of value in these amps.
They are rock solid and durable, and all it will take for people to start snatching them up is some big name displaying them and talking about what a bargain they are-kinda what Jack White did for all those Silvertone cardboard amps languishing in garages and basements all over the continent.
Until that day arrives, however, they can be had for a song. The one that is on its way here cost me a cool $229 plus $45 for shipping-not a lot of money for a 100w combo that's built like a Pershing tank. The going rate seems to be about a couple hundred dollars give or take so stock up while they're cheap. If I'm correct they won't stay that way forever.
After doing some basic freshening up with new electrolytics-I am waiting for the 2.2 uf 50 volt numbers and some new zener diodes to put things back together-I thought an adjustable bias control would be nice.
The earlier iterations of the Artist had this feature, but later ones did not-bias is set with a 68k resistor.
I took a 100k 25 turn trimmer pot from my stash, adjusted it to 68k and installed it where the original resistor was placed. As the legs are a little short to stretch comfortably I installed a chunk of solid wire bent into a dog leg shape so that the one leg of the pot could be comfortably wrapped around it and soldered and the other leg dropped right in.
Job done, as Edd China says.
UPDATE: I reassembled this amp today and found something interesting. I had set the trim pot to 68k so as to get the amp in the same configuration as before. It only showed about 12ma on each tube which is ridiculously cold bias. At a plate voltage of 490v, this was far too low. After adjusting the bias upward to about 37ma each on a new set of 6L6GCs from the house of JJ, the outcome was well worth the gamble. Lots of volume and good tone. I've got a set of Ruby 6L6GCs that are going into my amp tomorrow.
It also gave me a chance to download and view the owner's manual which explains the function of the automix input. The idea is when it is activated it uses the bright channel to overdrive the normal channel-I think- or maybe it was the other way around. Either way I'll skip it. My amp awaits a similar tuneup on the workbench.
The take home from it is if you have an old Peavey it is well worth the effort to install an adjustable bias control at the next trip to the amp tech. It will improve things a plenty.
UPDATE 2:I completed the overhaul on my Artist and all appeared in order, after I'd replaced the 100 ohm screen resistors with 470 ohm 5w resistors. Two of the originals were open.
After it went in the cabinet and I powered it up, all was good until it started spitting and humming and two of the power tubes red plated. Something had happened and it wasn't good. Careful inspection revealed that wiggling one of the power tubes around produced a crackling and the usual blue glow was interruptible. The sockets did seem awfully loose.
As I was watching the Giants take a dump tonight I took the time to tighten the tube pins-there are two types of pin receptacles. One is a round type and the other looks like a potato fork with the middle tine missing. These were the latter type-easier to tighten. So, 16x4 = 52 pins later the problem was solved, and I got myself a sweet quad of STR387s by knocking twenty five bucks off of the bill for the other amp. So, between the quad of oldish Groove Tubes made by Sylvania and the STR387s I'm in good shape with the glassware.
The idea sounds so good that I went and acquired one from Music Go Round and it should be here tomorrow if UPS doesn't ruin it.
Overall it's a nice idea well executed. The preamp integrated circuits are all socketed for easy changeouts and it's modular with a preamp board, a power supply board and a tube board. It was built with all Nichicon electrolytics-good material for durability and initial quality. The traces are easy to manage and it doesn't have any of that confounded no lead solder mucking everything up.
The only thing I don't like much is the fact that the power tube sockets are riveted to the chassis and soldered through the tube board. It could be an issue if a tube socket ever had to be changed.
These are the amps that Hartley Peavey made his fortune on, and it's a shame that Peavey has lost their way and become just another importer of Chinese made stuff of indifferent quality. You may have read my earlier missive on the Peavey Valve King 100 and what a steaming pile of crap it is.
With rare exceptions that is what Peavey became. I understand that the 5150 and 6505 heads are liked by fans of heavy metal but that's about where it stops. I've had my eye out for an early Peavey Vintage for some time but not a one has surfaced-that's the all tube 100w Fender Bassman with reverb-what a great idea.
I am of the opinion that at some point people will recognize that there is a lot of value in these amps.
They are rock solid and durable, and all it will take for people to start snatching them up is some big name displaying them and talking about what a bargain they are-kinda what Jack White did for all those Silvertone cardboard amps languishing in garages and basements all over the continent.
Until that day arrives, however, they can be had for a song. The one that is on its way here cost me a cool $229 plus $45 for shipping-not a lot of money for a 100w combo that's built like a Pershing tank. The going rate seems to be about a couple hundred dollars give or take so stock up while they're cheap. If I'm correct they won't stay that way forever.
After doing some basic freshening up with new electrolytics-I am waiting for the 2.2 uf 50 volt numbers and some new zener diodes to put things back together-I thought an adjustable bias control would be nice.
The earlier iterations of the Artist had this feature, but later ones did not-bias is set with a 68k resistor.
I took a 100k 25 turn trimmer pot from my stash, adjusted it to 68k and installed it where the original resistor was placed. As the legs are a little short to stretch comfortably I installed a chunk of solid wire bent into a dog leg shape so that the one leg of the pot could be comfortably wrapped around it and soldered and the other leg dropped right in.
UPDATE: I reassembled this amp today and found something interesting. I had set the trim pot to 68k so as to get the amp in the same configuration as before. It only showed about 12ma on each tube which is ridiculously cold bias. At a plate voltage of 490v, this was far too low. After adjusting the bias upward to about 37ma each on a new set of 6L6GCs from the house of JJ, the outcome was well worth the gamble. Lots of volume and good tone. I've got a set of Ruby 6L6GCs that are going into my amp tomorrow.
It also gave me a chance to download and view the owner's manual which explains the function of the automix input. The idea is when it is activated it uses the bright channel to overdrive the normal channel-I think- or maybe it was the other way around. Either way I'll skip it. My amp awaits a similar tuneup on the workbench.
The take home from it is if you have an old Peavey it is well worth the effort to install an adjustable bias control at the next trip to the amp tech. It will improve things a plenty.
UPDATE 2:I completed the overhaul on my Artist and all appeared in order, after I'd replaced the 100 ohm screen resistors with 470 ohm 5w resistors. Two of the originals were open.
After it went in the cabinet and I powered it up, all was good until it started spitting and humming and two of the power tubes red plated. Something had happened and it wasn't good. Careful inspection revealed that wiggling one of the power tubes around produced a crackling and the usual blue glow was interruptible. The sockets did seem awfully loose.
As I was watching the Giants take a dump tonight I took the time to tighten the tube pins-there are two types of pin receptacles. One is a round type and the other looks like a potato fork with the middle tine missing. These were the latter type-easier to tighten. So, 16x4 = 52 pins later the problem was solved, and I got myself a sweet quad of STR387s by knocking twenty five bucks off of the bill for the other amp. So, between the quad of oldish Groove Tubes made by Sylvania and the STR387s I'm in good shape with the glassware.
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