Alembic Guitars Club
Alembic products => Owning an Alembic => Troubleshooting => Topic started by: lozbass on March 21, 2010, 03:44:44 AM
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Hi all, this could be a common issue and I've tried to search for answers before posting - my apologies if I've missed something.
I've been using my Series II with a standard mono jack connector most of the time (just for convenience at home and rehearsal). I've been doing what you'd do with a standard Fender type bass - (good quality) mono jack lead into bass - other end into amp: just quick and easy. However, I've noticed that I get some interesting pickup and control combinations - certainly different than using the stereo lead into the power supply! Can anybody suggest what I should be doing differently? Is there some form of special wiring for jack leads (possibly a stereo jack) that I should be using? If so, given that I'm pretty useless with a soldering iron and electronic components, is there anybody - or any company - that can supply the requisite lead. Again - apologies if this is a stupid question (or one that has come up before)...by the way, I'm in England but more than happy to import the requisite solution. Cheers, Lozbass
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I'm not quite sure what you mean by differences.
Are you talking about the volume differences when only one pickup is active and both pickups are active in mono mode? If the answer is yes, then this is normal. In mono mode the preamps are additive so you will have a volume increase when both are on.
If this is not what you are talking about could you please give more details?
Keith
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When i use standard mono jack my bridge pickup vol knob becomes a Pan control & my master vol is just overall vol......but when i use the power supply jack (with a mono cable into the bass as well) my neck pickup vol becomes a pan pot......giving me the ability to pan both pickups thru the right thus keeping the bridge pickup solo in the left amp if running stereo
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Lawrence,
If your 1/4 jack on the bass is wired in stereo (which is the case in pre-1988 models) you will need either a stereo 1/4 cord into 2 channels (split into two 1/4 plugs) or a 1/4 stereo plug with 2 summing resistors into 1/4 mono plug. I just built such a cable for my 1982 SII and it works fine, summing the two P/U signals into mono. You can find information on how to make this cable in the FAQ and Must Reads section under FAQ , Series I and II, wiring a ?? stereo to ?? mono cable (sorry, I don?t know how to post a link to this). If you know somebody with basic soldering skills they can easily make this cable for you. I hope that helps.
Alan
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Here you go...
Wiring a 1/4 Stereo Cable (http://club.alembic.com/index.php?topic=274)
Wiring a 1/4 Stereo to 1/4 Mono Cable
Summing Gizmo (http://club.alembic.com/index.php?topic=11832)
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artswork99,
Is the summing gizmo the way to sum the Channel A & B outputs of a Superfilter as well (preferred); or is the Stereo to Mono thread of Mica's (also?) the correct procedure? (I will still check with Mica).
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I made the gizmo for myself because I have an old power supply that did not have the mono switch (worked great for my application). Essentially it should take any two inputs and sum them into one output. I don't see any reason why it wouldn't work to sum the A/B outputs of the Superfilter. Always good to check with the experts though!
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Thanks (to artswork99). I appreciate it.
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Hi all, thanks very much indeed for your help - I think that I'm starting to understand what is going on. My apologies too - I should have supplied more information - the bass is a 2008 build. I'll act on some of the ideas/information above and see where it gets me (I think I need to do a little more trialling with the bass - always a pleasure!) I'll report back - thanks again - the help is much appreciated.
I should also get some images up here too - for anybody with an interest, I have some on Basschat in the UK at:
http://basschat.co.uk/index.php?showtopic=26098&st=60 (http://basschat.co.uk/index.php?showtopic=26098&st=60)
(second post down - number 62)
Cheers, Lozbass
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Beautiful bass! Is the switch near the 1/4 inch jack a stereo/mono switch for the 1/4 output?
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Looks like you have both Mono and Stereo capability out of the 1/4 jack, so with the switch (I assume it's a Mono - Stereo switch) in the mono position, any regular guitar cord will work fine and you'll have both P/U outputs summed into mono. For stereo, you'll need a stereo cord split into 2 mono 1/4 plugs.
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Hi all, I feel a little foolish and embarrassed now! You're absolutely right, the switch is stereo/mono. Though there's little defence, I didn't spec the bass but bought it from a friend who did (I should have asked him!) I think that's my question fully resolved - thanks to all for the prompt and very helpful inputs. I'll approach an electronically literate friend to supply the requisite split cord. Thanks again for all the help
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Couldn't had done it without the additional info and pictures that you supplied. Glad that your questions have been answered. Regards from across the pond.
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Hi again - thanks to all - problem now solved (and new cable in production) - regards from England!
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I just ordered a 6,3 mm mono female > 6,3 mm stereo male Jack from a Dutch electronics webshop. Cost me 5 euros delivered. I'll let you know how it works, but theoretically it should do the trick with the help of two 9V Duracells.
Wilfred
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Wilfred,
Does it include the 20K mixing resistors? Just shorting the two outputs together would not be a good idea.
Loch
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No it doesn't, but I'm pretty sure it will work. I've used a mono guitar cable before on which one of the jacks was replaced with a stereo jack, and it worked fine. But I'll let you know as soon as it's here and I've tried it!
Wilfred
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Update: the 6,3 mm mono female > 6,3 mm stereo male jack works like a charm! The biggest difference is that you have to use batteries. My Series I has the the pickup selector permanently on both (it's removed from the lower horn and hidden in the body cavity) so for pup-selection I'm already used to use the volume controls. I've found that if I want to use one pickup only , I have to add a tiny bit of volume for the other. I'm not technical at all, but there seems to be some kind of threshold. All in all a very easy and great solution!
Wilfred
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You're hearing what's expected if you don't have the mixing resistors. When you turn the volume of one pickup down, you're shorting it, and the over all sound has this in it too. With the mixing resistors, you can turn one pickup completely off with the volume control.
You can add the resistors inside the connector you purchased if there is room. We usually use 1/4 watt but you can use 1/8 watt if the space is really tight inside.
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(http://club.alembic.com/Images/394/78795.jpg)
Well, it's this one, no room inside I'm afraid. It works for me, as a plan B option so to speak, or to use at low volume in the living room with the little practise amp I've got hidden behind the couch... ;-)
Wilfred
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Wilfred,
If you're very careful, there is room inside that jack to wire in the resistors. You will need to use 1/8 watt or smaller resistors instead of the usual larger 1/4 watt ones.
Loch
(Message edited by lmiwa on April 16, 2010)