Alembic Guitars Club
Alembic products => Owning an Alembic => Troubleshooting => Topic started by: edwardofhuncote on November 02, 2019, 09:29:17 AM
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This isn't as much a troubleshooting query as it is general question...
On an older power supply, one without a stereo/mono switch, and one that apparently doesn't automatically mono output on the bass jack, how would one go about summing these two 1/4" outputs and sending them to an F-1X input? (yeah, I know... I need an F-2B. ::) ) The unit in question works just fine, one jack at a time, and to be clear, I do not want to modify the unit, but it would be nice to use it here in the practice room.
Is it any more complicated than a simple Y-adapter?
https://www.musiciansfriend.com/accessories/rapco-horizon-1f-2m-mono-1-4-guitar-y-cable/336201000000087?pfm=item_page.rrCompare (https://www.musiciansfriend.com/accessories/rapco-horizon-1f-2m-mono-1-4-guitar-y-cable/336201000000087?pfm=item_page.rrCompare)|ClickCP
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you could try a really basic low cost two channel mixer like this one i found on Thomann.
https://www.thomann.de/gb/millenium_pocket_mix.htm
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I wonder if it has already been modified or a connection has failed. All of my older DS-5 units output mono through the bass 1/4 out. Have you checked inside to see how it looks?
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I am with Rob on this, my only experience with an older DS-5 is the one that came with my 78 bass but I was under the impression that all the older ones were designed to provide mono output through the "bass" jack. It sounds like yours is either not working properly or has been modified. A simple y-connector should work but if it was mine I would just get it serviced so it works again as intended. If there is no mono output how have you been using your DS-5 to date?
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Knowing where it came from, it is entirely possible that it was intentionally modified to function this way from the start. It's also possible that something has failed. Don't know, but it works fine with two 1/4" patch cables into a Y headphone splitter, except that renders the pickup selector switch on my Series bass useless except for the switch positioned with 'both' pickups on. Of course, then I can just use the Volume controls for each pickup to mix... which works fine too. But any other switch position 1, 2, or 4 is dead. (don't laugh - I had a Volkswagen once that wouldn't start unless you turned the headlights ON.)
Again, each output jack, whether out of B or T works fine individually, but activates only bridge (T) or neck pickup (B) when used like you'd normally use a DS-5 in mono mode. I think they are both on, all the time. So I think if I had a real mono/mono male > mono female Y-adapter, it would work correctly, and my basses pickup selector switch would work too. But, I digress...
Yeah... it's a puzzle. If I can get around it with a simple solution, that'd be great.
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The blue boxes that came with my ‘76 Series I guitar and ‘77 Series I 12 string guitar both provide a mono output like others have described above.
Bill, tgo
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Even though FCs old thread is about modifying a DS-5 it looks like the schematic posted in the thread shows how it should be wired to be stock. It is possible one of the summing resistors failed or someone re-wired it, should be an easy fix. At any rate maybe the schematic will be helpful to you in terms of understanding how it should work and allow any competent tech to troubleshoot and do a repair. Good luck!
http://club.alembic.com/index.php?topic=4526.msg54356#msg54356 (http://club.alembic.com/index.php?topic=4526.msg54356#msg54356)
[replaced link to current Club topic]
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Hey Greg,
I agree, all the stock DS-5s I've ever seen were built with the mono output option when using the "bass" jack only. Could you humor us by unscrewing the feet, sliding the cover off, and posting a couple pics of the 1/4" jack area?
To keep everything legit you want to use summing resistors instead of a simple 2-to-1 Y-cable. The idea is to avoid connecting the output of one channel directly to the output of another which might irritate your op-amps... The schematic posted in the thread above shows 20k summing resistors. If for some reason your DS-5 is permanently wired in stereo you can also make a simple summing cable with resistors in it to do the job.
Pics??
Jimmy J
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Hey, Thanks Jimmy J., Stephen, Rob, Bill, and Jazzy.
Yep, I was kinda' expecting it to work like the two blue DS-5 units I have, but this one pre-dates them both by quite a bit, so I wasn't sure if it came this way. (still not) I kinda' suspect it was set up to run as a 'stereo-only' box, maybe from the get-go. I may need to send it back to Mr. W. sometime to get where I need to be.
In the meantime, I can just play with it as-is. There's a kinda' neat backstory on this box I'll tell you all about if I ever get all the facts straight. It's a silver box, early 1973 issue. Doesn't sound a bit better than the DS-5R, and it sure doesn't make me play any better, but it's infinitely cool to look down and think about what a quantum leap in active electronics that little silver box represents. 8)
*I would Jimmy, but unscrewing the feet doesn't take this one apart... there are quite a few screws. I'm up in the Shop now, but I'll snap a few pictures later on of it.
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Pics...
So there were 4 sheet metal screws on the bottom, 2 more on the right-hand side, and the top lifted off. I was expecting to find elves and pixie dust... ;D
You guys see anything obvious here?
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Wow! Historic indeed. Was that actually built by Alembic?
That box is stereo only so you'd need to modify it to get a mono signal. And as you see there is very little room to do anything in there, possibly even too tight to fit the "standard" switching 1/4" Treble jack... There may be room for a switch above the 1/4" jacks, if it would clear the caps... But you'd need to pull all the components out to do any work on it.
Or, as I said, if you get a couple 1/4" plugs large enough to squeeze in a resistor to the tip between the tip and the center conductor of the wire, you could build a "summing" Y-cable.
We might need the back story!
Jimmy J
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Is that a DS-2?
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Two fair questions, and I can't answer either one.
I called it a DS-5, but in truth it can't be. I guess it would more accurately be described as a power supply for an Alembic Series instrument, before they were called Series instruments. It has a much less 'finished' look than other DS-2 boxes I've seen, but then, I haven't seen too many. Bass #73-43 is on Reverb now with a DS-2 stamped with a "17". I notice that it also has a selector switch between the output jacks, presumably for stereo/mono operation. https://reverb.com/item/13291506-1973-alembic-series-i-lb-1-w-ds-2-power-supply
Was it made by Alembic? Supposedly, but it doesn't say that anywhere on it. It has a certain handmade quality, but one that says this wasn't the first or the only one. I know for certain it was used with a 1973 Alembic bass. I don't know if this was the original power supply issued with that bass, or a backup, or one that was made expressly for some purpose. (like stereo-only) The only markings are a very faint number on the front from model paint or sticker residue maybe. Not sure if this number was a reference to anything other than the bass it was used with.
Anyway, it's a very cool little box with a past... I will probably just rig up a summing Y-cable with some resistors (Thanks Jimmy J!) so I can use it here in the practice room. I will need some help with that, as I am quite an electrical Dunce. Note well, the capital D, Friends.
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I don't see the number you're referring to; only the B for bass and the T for treble.
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Hey Greg,
It's clearly a handmade unit which is cool and you may not want to modify it because of its history. So yeah, it's pretty easy to make a summing cable, but WAIT... Here's a quote from the F1-X manual regarding the TWO input jacks:
"... Two instruments may be played simultaneously by using both jacks, the signals will be equally weighted..."
In other words, try just using two cables from your DS-5 and the F1-X should do the summing for you. :D
Jimmy J
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Awesome, thank you Jimmy J... just try reading the manual, right!? I'll give it a rip. 8)
Thanks All. :)
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Aside from the overall innovation of having an external power supply for our instruments, the actual hardware part of that PSU isn't anything too wild. The preamp boards can operate on anything from +/- 9v (batteries) to +/- 18v (DS-5) or maybe even more. I've made several purpose built PSUs running at +/-15vdc which have been solid operators for years.
On the audio side, Alembic's lo-z opamp output signals allow for some very creative signal routing and manipulating.
Here are a couple pics of my modified DS-5s. Excuse the home-made looks. Ha! Plus the insides of one which may not have any original parts left. HA!
Jimmy J
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Cool pics Jimmy!
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As an aside, that's a nice looking '73 at Gregory's Reverb link.
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Yes - dad confirms you need to summing resistors to make the Y cable. This is probably a DS-1 unit, or an early DS-2 unit. The one that is in the Reverb link above dad say had VERY few made with that decoration. He also said that drilling that sheet metal was very difficult.
I know DS-3 and DS-4 units exist, but I've never actually seen one! The revisions came quickly, and so there were very few units of them made.
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Thanks Mica, and Mr. W. 8)
There are at least three similar, but not quite identical units in the Series I Showcase threads. They are a little bit hard to pick out, since they aren't really the subject of the posts, but I had a pretty good idea my box was akin to them. I'll follow-up sometime on that cable. ;)
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Aside from the overall innovation of having an external power supply for our instruments, the actual hardware part of that PSU isn't anything too wild. The preamp boards can operate on anything from +/- 9v (batteries) to +/- 18v (DS-5) or maybe even more. I've made several purpose built PSUs running at +/-15vdc which have been solid operators for years.
On the audio side, Alembic's lo-z opamp output signals allow for some very creative signal routing and manipulating.
Here are a couple pics of my modified DS-5s. Excuse the home-made looks. Ha! Plus the insides of one which may not have any original parts left. HA!
Jimmy J
Jimmy.....in that bottom photo........Is that a Rabbit's Foot in the lower half? ;)
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Ha! Well that DS-5 has brought me some good luck. But no, it's an old style in-line fuse holder like the one below, velcroed in place.
Jimmy J
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Jimmy, I'm puzzled about what the fuse in the above photo of the in-line fuse holder is designed to protect...
Jon
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Jon,
Yeah, I know that looks weird (!!) but that's how they used to be manufactured and sold. The internal ends of that wire are crimped onto the fuse clips so it's meant to be cut and inserted into the circuit.
Jimmy J
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...To keep everything legit you want to use summing resistors instead of a simple 2-to-1 Y-cable. The idea is to avoid connecting the output of one channel directly to the output of another which might irritate your op-amps... The schematic posted in the thread above shows 20k summing resistors. If for some reason your DS-5 is permanently wired in stereo you can also make a simple summing cable with resistors in it to do the job...
So, if it isn't much trouble to build, it seems like this is what I'd like to do here. I have tested a couple different scenarios to make sure the box is actually working correctly, including Jimmy J's idea of simply connecting 1/4" leads from both the B & T jacks to both 1 and 2 inputs on the F-1X, which automatically summed them; this makes everything work exactly as it should... switching on my bass returned to normal, access to either individually, or both pickups. (or standby, of course)
If I go out to play somewhere though, I'd need a way to adapt the two 1/4" outputs marked B & T, to a signal my amplifier input can accept, and won't confuse my Series I as to what's happening down the line. (I still can't get my head around this... how does it know, and why does it care?) I do have a local pro-audio shop that can probably/definitely handle this if I can't, but as is painfully obvious - I haven't the first clue what to tell them I need here.
Is there a picture or a diagram somewhere I could provide them with, to make such a thing? Foremost in mind, it has to be something that works reliably and won't mess up my bass. On that subject... I guess I'd know if I had done any harm by now, by using the consumer-grade Y-adapter I had... it doesn't seem to have hurt anything, just didn't work right. (see post #1) I have found another use for it, since then.
Thanks Again, All.
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Hey Greg,
Here's a crude schematic of a summing Y-cable. It's pretty simple and anybody who can make cables for you should get the idea. The resistors can be either in the plugs (as drawn) or in the in-line jack, wherever there is room.
If you're thinking about this for use when rehearsing or jamming with somebody else's gear, it might be simplest for you to use the 1/4" output from the bass. And the next question is ... does your bass's 1/4" jack have the mono mod or is it a stereo jack? Because if it's stereo, the same situation would apply there. :D
Jimmy J
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This guy makes the summing cables:
http://bayoucables.com/index.php?main_page=index&cPath=4
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Thanks a lot Jimmy J. and Michael D... appreciate it fellas. :)
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It's worth posting the rest of the story I guess... at least the part of it I know about.
Turns out this box is actually a DS-1 or maybe an early edition DS-2, though I am not sure what the technical details differentiating those are. This one is stamped on the back of the case, 27, using (I think) the same stamps that were used to stamp serial numbers in the headstocks of the instruments at that time. (note the size and font of the 2 and 7 stamps in the serial numbers) At one time it also had a painted or decaled number on the front that had faded to nearly illegible by the time I got this thing. I finally found some vinyl transfers that were pretty close to correct, and replaced them. After cleaning up the metal case a little, (whatever metal they made these boxes from, it tarnishes severely... is it nickel-plated maybe?) Finally, for a little class, I added a brand-new full color Alembic logo sticker to the top.
The backstory; I got this thing a little while back when John McVie surplused some gear... very soon afterward, I discovered he had gotten this box from a Club Member here several years before, perhaps to enjoy the cool numerical coincidence of having a power supply with the same number as his #73-27 bass. Maybe I'll get a chance to ask him sometime. So anyway, mine now... nothing magical here, it's just a cool old handmade box from the early days at Alembic, and a history that includes at least three other Alembics...
...but for now, DS-1 #27 is now assigned to duty with Series Bass #77-621... fits right in the upper pocket of the old blue case.
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:)
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This guy makes the summing cables:
http://bayoucables.com/index.php?main_page=index&cPath=4
I just want to add that Butch is a straight up guy and does a very good job of soldering. This use to, and might still be, a side job for him so he can get backed up but he was always honest with me about longer delivery times. I've bought speaker cables for my PA and a 1/4" Y cable for my Brown Bass from him. I would purchase from Butch again if I needed anything I didn't want to make myself.
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He sure is. I had a great exchange with him, and he was very helpful. I was going to have a local shop here fix me one up, but Butch knew exactly what I needed already. I have a Bayou adapter on the way so my old Alembic power supply will be easier to use.
I'd just like to tell everybody here Thanks Again too... it's so great having access to knowledgeable folks. I'd be in the tall grass without ya'.