Tube Amps / Music Electronics
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|6/7/2000 8:37 PM|
||ELK "Stage-Man" arrived...|
The Elk “Stage-Man” that I bought on eBay last week arrived last night, and I have to say, its pretty cool, all things considered. I say that without having had a chance to demo it yet (I got home late last night).
The amp is a basically a Princeton Reverb (single channel) with a 12” Alnico speaker (Japanese), an EZ80 or EZ81 rectifier, (couldn’t read the faded printing) a 2x6BQ5, cathode-biased output section & 4 twin-triodes up front: 3x12AX7, and a 6AQ8 for the reverb driver. It was late, so I may not have this right, but I looked it up and I think it said it was designed for use as a converter in TVs or something. I do know that it is a twin triode with an amplification factor of 57, so it makes some kind of sense that it was used as a possible 12AT7 substitute in the driver spot.
The feature set, from L to R on the front panel, is: 3 input jacks, Reverb Volume, Volume, Bass, Treble, Tremolo Speed, Tremolo Intensity, Pilot light. The rear panel has 2 RCA jacks for foot switching the tremolo & reverb, the fuse, the ON/OFF switch (no standby, just like a PR).
Cosmetically, the amp is in pretty great condition. The Tolex is a tad dirty, there are 2 knobs missing, and the tube guard panel on the rear is missing, but the faceplates are REALLY clean, and the tilt-back legs were intact, & the chrome looked excellent. (My 1st tilt-back amp! Cool). The Tolex was very clean, in terms of wear – mostly just needs a little elbow grease with a brush & some 409 to get out all the gunk & dust from those little crevices. The chassis has no rust or pitting/corrosion of any kind, and all the original parts were present. This amp looks like it had never been serviced. One thing that I noticed immediately was the bypass cap across the 6BQ5 cathode resistor had puked its guts out. I figure the 1st step is to replace that and then power it up.
The layout is kind of uninviting at 1st glance, as the main board is a thin (maybe 1-1/2” x 10”) phenolic job with roughly 15 solder lugs per side. The top of the board houses mostly resistors, while the underside held mostly caps. I did take some comfort in recognizing that the board could be flipped up for servicing with the de-soldering of 3 ground connections and 2 signal leads, plus popping the standoff nuts. So 7 steps to heaven there. Not as bad as I had thought, but still kind of a pain.
They also did some annoying stuff to save on production & parts count. They hard-wired all the reverb tank leads; This saved exactly 4 parts and made it impossible to pull the chassis without taking out the staples holding down the leads to the cabinet, pop the nuts off the tank, pull it, THEN pull the chassis, making sure not to jab the tank through the speaker as you remove the whole mess. Again, not a huge deal, but certainly a lot of hassle to just have saved 4 parts and a few minutes labor on the line. But hey – who cares. I’ll just drop in some jacks.
The reverb tank was a Japanese model that was narrower than Accutronics', and 2 hefty-looking springs… their diameter was roughly ¼”. There was a tank bag made of some cheap-looking vinyl that was crumpled/stuffed into the back of the cab, but the tank was loose in the cab.
I liked the fact that the tone components were mounted directly to the pots, with the help of a small lug strip. Much of the signal path is shielded, and the grounding seemed to make pretty good sense, what little of it I could grok at 2 am. Ultimately I will probably drop in a new custom board, ala Fender…there is plenty of room…the chassis is about 19-3/4W x 7”D x 1-3/4”H, so its somewhere between a PR and a DR, but narrower from front to back. The knobs are ugly: they look like Radio Shack crap, and will be replaced with the cream Fender-type barrel knobs, like those found on blonde/brown-era Fenders.
The resistors are those ATLAS olive-colored dog bone types, and the caps are mostly ATLAS oil-filled gray barrels. LOTS of electrolytics in places that typically use non-polarized caps. I heard that these caps were not of the best quality when I posted last week… I forget who mentioned that they had had to replace several, if not all of the coupling caps. The whole thing looks like it could have come from the same factory that made the SONY stereo reverb unit that I have. Seems like a lot of the Japanese stuff I’ve seen from the 60’s used these same parts.
The workmanship is quite good, and the layout makes decent sense but there are some cheap-o parts. The sockets are not too bad, but they *are* cheapies, and are affixed to the chassis using the cheesiest-looking rivets I’ve ever seen. They looked harmless enough from the outside of the chassis, but from inside, they look like they are made of tin foil. Those are high on the list of things to replace.
I’ll post again tomorrow, after I’ve replaced that cap and powered it up. I expect the speaker to be replaced, and I may build an alternate baffle for a ceramic 15”. Interesting amp. Kind of a Japanese cross between a Fender Princeton Reverb and a Vox AC-15. That reminds me…I didn’t think to notice if there was a NFB loop. Can’t wait to get home tonight and try it out.
All comments/suggestions are welcome…
|6/7/2000 9:29 PM|
I've worked on a few of these and all things considered, they are pretty decent amps. I've never had any problem making them sound damn good. Get some of the cheesy components replaced and you'll have a cool amp. You might want to spring for a new reverb tank, and maybe build a new circuit board for it, but you could probably use it like it is after nixing the cheese flavored caps and resistors.
|6/8/2000 9:49 PM|
Thanks for the response, Peter.
Last night I spent what time I had getting the amp in shape...I replaced the bad bypass cap on the 6BQ5's and also replaced the filter caps, then plugged it in.
The amp has a hum problem, a blown speaker, and the tremolo dosn't work. I wondered later whether the tremolo FS jack is rigged so that the effect is always off when the footswitch isn't plugged in.
Re: the hum, I tried pulling each of the tubes, starting at the preamp and working my back to the PI, but that proved to not be the source. I may need to check my grounds.
The reverb is kind of weird; it sounds like a cross between the lousy stock Silvertone reverb and a Fender reverb. Kind of clangy/washy, but with a fairly nice, long, wet decay. I may try tweaking the grid resistor on the driver to bring the dwell down. I'll probably take your advice and swap in an Accutronics tank.
This amp is not even as loud as my PR, which surprised me. There is a 260-0-260 PRI winding designation on the PT. Not sure what that rectifies out to...the cathode resistor is 130-ohm bypassed w/30uF-16v (or at least it was until I swapped in a 22uF-35v).
Not a bad-sounding amp upon 1st listen, but there is plenty of room for improvement. I'm debating on whether or not its worth it to try tweaking the amp as is, or alternately to build a new board and start fresh. I'm halfway tempted drop in a new set of trannies and make it a 4x6BQ5 rig. Lose the tremolo and the tube rectifier and I might be able to keep the reverb. I could use the freed up tremolo control holes for the other 2 knobs in a 3-knob reverb setup. Hmmm...
I kind of hate to change the feature set though...we'll see.
|6/8/2000 11:07 PM|
No Hacking vintage equipment!! :>
|6/10/2000 12:15 AM|
I sit corrected, my man. Dig it. ; )
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