Pickup/selector and PSU issues with my newly acquired '79 Series 1

[mica]

Make sure your power supply is in the mono switch position or you are using the bass/mono output. What you are describing is what happens when your bass is coming out stereo but you are using a mono output. The knob placement on the switch should have no impact.

[Clarky]

Sorry Mica, thanks for clarifying about the pickup selector but I am confused. Apologies if I am saying something totally rookie here, but there is no switch on my DS5. The front panel has two 1/4 outputs (Bass/Mono and Treble) as well as the 5 pin input. So how do I select the power supply for mono switch position?

[mica]

Use the bass/mono output on the DS-5 if you want the mono output. There are indeed a few versions.

[Clarky]

Apologies but that is what I was doing (using bass/mono output; and separately trying the treble output). Am I creating a stereo/mono mismatch in so doing? If so how can I work around this please?

[jazzyvee]

Clarky I have one of those un switched PSU boxes that I use with my 1980 S1 and I get both pickups out of the mono and get individual outs if I use a jack in both sockets. Like yours my old S1 still has the stereo jack. One of the members here George Price (geepee) lives somewhere in London so it might be worth contacting him to see if you could meet up to try your bass through his DS-5 just to see if there is problem with your PSU or your bass.  Failing that I'm in London on a seminar next week either Thursday and Friday or Friday only so I could bring my switched one for you to try depending on what time we both have free during the evening before my train back. I also have a PJB headphone amp that I could bring if that would  help.

[Clarky]

Thank you for the kind offer JV, although I will be away when you are down in London. I think I need to try out the stereo to mono lead which I have on order (hopefully I will get it by the weekend or early next week at latest, before I head off). Then I can work out whats going on (I think!)

[mica]

If you use both outputs you simply get one pickup per output - you will of course need to use 2 amplifiers.

If you want to use a mono amplifier, just use the bass/mono out out on its own. It sounds like you have the operation under control.

You can test the 1/4" output wiring by plugging stereo headphones directly into it. You should hear one pickup in each ear. If you can do this test, please post back with your results.

For the 5-pin output, you will need to test with another unit as Vince describes, or take it to a service person to test. I can send you a schematic if you need it. I suppose we need to confirm that the 1/4" output is working properly, and then figure if the 5-pin cable or the DS-5 is preventing one pickup from getting to your amplifier.

[Clarky]

Ok, the stereo to mono cable arrived and - as I feared based on the 'headphone test' - the situation is the same. Neck pickup sounds great and can be selected from positions 3 and 4 of the selector switch. Bridge pickup is totally silent so position 2 of the selector switch produces no sound whatsoever. At least this isolates the issue to the bass, not the DS5. However, I do not know where to go next? If it helps I have taken pictures of the electronics which I will attach in my next post.

[Clarky]

Pics

[gtrguy]

"Uh, did you switch the pickup jacks around on the PF6 card to check if the pickup that doesn't work will work when it is switched? Don't plug it into the dummy PU spot."

Sounds like either the selector switch or you have a dead pickup.

[Clarky]

Hi gtrguy, thanks for your reply. Unfortunately I have no electronic understanding at all so talk of the PF6 card and switching things around terrifies me! I would likely damage the instrument due to my lack of understanding.

Guess I am going to have to take this to a technician (hope there is one in London who knows how to work on Alembic electrics ...) if there is no simple fix

[mica]

Reverse where the red and blue labelled pickups are plugged into the card. Then report if the position of the functioning pickup changes, stays the same, or if everything is dead. You can plug them back in regular when you've completed the test. This will let us know if the preamps card or one of the pickups is the culprit.

[Clarky]

Hi Mica, I just did what you suggested and swapped the red and blue inputs on the back of the card (not as hard as I had imagined, gtrguy, sorry!) - the result is that the functioning pickup remains the neck pickup, no change at all.

What does this mean? Thanks

[lbpesq]

It means the problem is with the bridge pickup, not with the card.

Bill, tgo

[Clarky]

It means the problem is with the bridge pickup, not with the card.

Ok thanks. So what are my options here? New pickup or get wiring/electronics checked out by a technician?