Older DS-5 question

[edwardofhuncote]

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|ClickCP

[jazzyvee]

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

[rv_bass]

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?

[StephenR]

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?

[edwardofhuncote]

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.

[lbpesq]

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

[StephenR]

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


[replaced link to current Club topic]

[JimmyJ]

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

[edwardofhuncote]

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. 

*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.

[edwardofhuncote]

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... 

You guys see anything obvious here?

[JimmyJ]

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

[jwright9]

Is that a DS-2?

[edwardofhuncote]

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.

[David Houck]

I don't see the number you're referring to; only the B for bass and the T for treble.

[JimmyJ]

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.   


Jimmy J