| Author | Message | ||
| sscastro
New Username: sscastro Post Number: 6 Registered: 2-2005 |
Hi, about 5 years ago I was in contact with Mica, about a bass I have, apparently the only 10 wood layer bass ever made at Alembic, which has all Alembic parts, including the external pre-amps, but a different peghead. I remember someone has identified it has a custom made instrument by one of the elder luthiers at the factory. Anyhow, the important thing is that it is noisy and almost impossible to use, because the switch broke when shipped and I need to make sure the connections are right. And at the moment they are not. Could somebody please help with that. Apparently it is from the mid 70s and the switch has 10 contacts (or should it be 12?). It's the usual 3 pick-up lay-out. | ||
| tbrannon
Senior Member Username: tbrannon Post Number: 1251 Registered: 11-2004 |
I think some pictures are in order!! Some others will be along shortly to help you out with the electronics, I just want a chance to gawk at the pictures  | ||
| mike1762
Senior Member Username: mike1762 Post Number: 666 Registered: 1-2008 |
Yea, I'd like to see some pics. I assume one of the 3 "PUPs" is the dummy coil. | ||
| mike1762
Senior Member Username: mike1762 Post Number: 667 Registered: 1-2008 |
 My last post!!! | ||
| hankster
Advanced Member Username: hankster Post Number: 244 Registered: 6-2004 |
Have I missed something here? Mike, are you ok? | ||
| elwoodblue
Senior Member Username: elwoodblue Post Number: 1111 Registered: 6-2002 |
I was worried it was your last post, I see now you were just referring to your 'latest' post ....on to 777 edit-(didja notice my post# ?) Back to the topic...I'll third the motion for detailed pictures! Mica or others might be able to see something that is out of order and causing your noise issues. (Message edited by elwoodblue on October 23, 2010) (Message edited by elwoodblue on October 23, 2010) | ||
| mike1762
Senior Member Username: mike1762 Post Number: 669 Registered: 1-2008 |
My sense of humor is one of those that leaves everybody wondering: "WTF was THAT about"??? Let's see that 10 layer bass!!! | ||
| tmoney61092
Senior Member Username: tmoney61092 Post Number: 557 Registered: 9-2008 |
Mike got trips, Hankster got dubs, and elwoodblue got quads, it's the end of the universe!!! oh, and post some pics :-) ~Taylor | ||
| sscastro
New Username: sscastro Post Number: 7 Registered: 2-2005 |
Sorry folks, I'm on the other side of the pound, in Spain, so my time table is a bit different. These pictures have been around, about 5 years ago when I was trying to investigate about this "beauty". I stopped playing the bass in the early 80s, as for the last 30 years I kept attached to a project as a guitarrist and lead singer. Now I have to meet my old folks from the 70s, when I was playing the bass, as the band is being awarded after all these years, and I want to play it. This bass was bought in the UK, from a complete set of instruments that were resident at Electric Lady in New York. Apparently was one of the basses used to record "In from the Storm - the music of Jimi Hendrix" produced by Eddie Krammer in 1995, with an incredible line-up of excellent musicians. Anyway, the bass plays great, mechanically, but the wiring must be wrong. It was badly treated on the plane and the switch got broken. I changed it with a new 10 position one, trying to emulate what was in the original. Someone sent me information, about using a 12 position one, but I never tried it. So the bass is noisy. Although the bass seems to be not an official one - Mica said that once - all the electronics are genuine, so I'm hoping that a conventional diagram from that era will be fine to make it work properly again. I will have to post a few more pictures in a next post.  | ||
| sscastro
New Username: sscastro Post Number: 8 Registered: 2-2005 |
Hi again here are some more pictures.    another post to follow (Message edited by davehouck on October 24, 2010) | ||
| sscastro
New Username: sscastro Post Number: 9 Registered: 2-2005 |
these are the last pictures. Somebody help please. Thanks   (Message edited by davehouck on October 24, 2010) | ||
| terryc
Senior Member Username: terryc Post Number: 1387 Registered: 11-2004 |
Correct me please ccastro but are you referring to the power supply unit or the bass itself as I don't think any Alembic bass had a 12 point selector(well maybe Phil Lesh's!!) Does the bass run with batteries which are located underneath the square plate on the back? You can run this bass in mono with just batteries, that would get you going for the time being until your DS unit is fixed. Nice bass by the way..nice 'hippie sandwich' for the body | ||
| sscastro
New Username: sscastro Post Number: 10 Registered: 2-2005 |
Hi Terryc. Thanks. Yes the bass runs on batteries, but still noisy, out of the mono jack socket. The broken selector in the bass had 10 pin marked 1 to 10 plus the 2 in the middle of the circle made by the other 10. I was given a 12 + 2 pin selector to substitute, but I thought better trying to find another one similar to the broken one. And then I had the bass noisy, but maybe it was noisy before the shipping, I had not tried it, I only saw it physically and I bought it to add to my bass and guitar small collection. | ||
| sonicus
Senior Member Username: sonicus Post Number: 1357 Registered: 5-2009 |
I am very curious as to more history in the building of this seemingly rare fine specimen . It would be interesting to find out what year this instrument was built to know more about who was involved in its creation . (Message edited by sonicus on October 24, 2010) | ||
| davehouck
Moderator Username: davehouck Post Number: 9757 Registered: 5-2002 |
Nice bass! I've seen that same headstock design before. Someone with a better memory than me will probably be able to identify it. The bridge suggests that the bass was made after 1976. Do you still have the original selector switch? What may be helpful is to take some good quality close up pictures of the connections at the switch. Does the bass make noise in all four positions of the switch? | ||
| sonicus
Senior Member Username: sonicus Post Number: 1358 Registered: 5-2009 |
Dave , These five names appeared in my mind ; Rick Turner, Frank Fuller. Michael Dolan, Doug Irwin , Larry Robinson. Perhaps one or more of these craftsmen. | ||
| adriaan
Moderator Username: adriaan Post Number: 2638 Registered: 6-2002 |
Here's an earlier thread from 2005! | ||
| davehouck
Moderator Username: davehouck Post Number: 9758 Registered: 5-2002 |
I knew I had seen that headstock before! Thanks Adriaan! Wolf; in the thread Adriaan points to, Michael suggests Bruce Becvar. | ||
| sscastro
Junior Username: sscastro Post Number: 11 Registered: 2-2005 |
Hi Dave the bass only sounds out of 2 positions. There's also no stops so the switch goes around in circles. It's always noisy. I will get pictures of the connections and I will try to identify which wires come out of which pick-ups. | ||
| sonicus
Senior Member Username: sonicus Post Number: 1359 Registered: 5-2009 |
Oh yes, Bruce Becvar! Thanks . | ||
| lidon2001
Senior Member Username: lidon2001 Post Number: 442 Registered: 4-2005 |
ss, both outputs are normally stereo. You would have to get the proper 1/4" cable to hear both pickups. | ||
| davehouck
Moderator Username: davehouck Post Number: 9759 Registered: 5-2002 |
Sergio; I thought you said you had a new switch in place. Is the new switch going around in circles? The four positions are neck pickup, both pickups, bridge pickup, and standby. The standby of course should not have sound. I'm wondering if the position that doesn't have sound, but should, is either the "neck pickup only" position or the "bridge pickup only position". And I'm also wondering if you put the selector in the "both" position and then turn the volume knobs for the two pickups, is one of them not making any sound. Determining the above may help narrow down where the problem is. | ||
| davehouck
Moderator Username: davehouck Post Number: 9760 Registered: 5-2002 |
Thanks Tom; I missed that when reading his reply. Following up on Tom's point, are you playing through the IN-2 with the 5-pin cable, or are you playing through the 1/4" jack with a standard guitar cable? | ||
| sscastro
Junior Username: sscastro Post Number: 12 Registered: 2-2005 |
At the moment I do not have the IN-2 here with me, so I was going through a standard guitar cable, and you are right it should be a stereo one, even if ring and tip are soldered together, otherwise I was shorting one of the pick-ups. When I fitted the new switch I missed the stops, hence it goes round in circles. What I found some minutes ago, trying to make pictures from the connections is that there is an earth flat copper foil, glued to the bottom of the cavity, connecting the back plate, and to the switch. But it does not get there, as it is completely smashed and rotten. So I wonder if by making a piece of stranded sleeve going from the pots chassis to the switch chassis, the noise will simply go. I will try all your test recommendations, but I need new batteries also, as they are quite weak. thanks everyone. | ||
| davehouck
Moderator Username: davehouck Post Number: 9761 Registered: 5-2002 |
Sergio; the Series electronics run through batteries quickly, so getting your IN-2 and using that will be helpful. And yes, the quarter inch standard cable may be the reason sound was only coming from two positions. Simply soldering ring and tip together is not sufficient. Instructions for making a good cable can be found here. The pots are grounded to the shielding; so yes, if there is a problem with your shielding, that may be the source of the noise. You can purchase shielding paint from Stewart-McDonald and other sources. The shielding should be repaired as it protects the electronics from RF noise. | ||
| sscastro
Junior Username: sscastro Post Number: 13 Registered: 2-2005 |
Hi dave I took your advise and looked into the connections of the jack and all is according to stereo 1/4" wiring: On the grounding flag wiring all seem right too if "black to harness" means to pins 1 and 10 together on the selector switch, which is what I've got. Definitely I can't get the bass pick-up on its own, but I have them both after the bridge pick-up position. Another interesting point is that not all pots connect to ground. Bass pick-up volume pot does, but treble volume pot does not, both treble EQ pots are linked, but on the bass EQ only the first pot (closer to the knob) is linked. Also only one of the switches seem ground linked, the one amongst all 4 pots. By the way are they doing exactely the same, one for the bass one for the bridge pick-ups. I believe it's passive, active shelving and parametric. Could you please let me know? | ||
| slawie
Advanced Member Username: slawie Post Number: 268 Registered: 8-2002 |
Sergio would you be willing to part/sell off the IN-2 only? Is it voltage capable for Europe i.e. 240V? slawie | ||
| davehouck
Moderator Username: davehouck Post Number: 9764 Registered: 5-2002 |
Sergio; the entire control cavity should be painted with shielding. The shielding is the ground. When a pot is firmly attached to the body of the instrument, it is grounded to the shielding. If a pot is loose, the connection to ground is broken. The controls for Series I electronics are described here. It is all "active". And yes the setup for the neck pickup is the same as for the bridge pickup. Each pickup has a volume control, low pass filter control, and a Q switch, all described at the link above. If you do not have a stereo 1/4" cable as described in the link in my previous post, you will not be able to hear both pickups. However, what you may want to try is to plug a set of headphones with a quarter inch stereo plug into the 1/4" stereo jack on the bass. If the bass is working properly, you will be able to hear the neck pickup on one side of the headphones and the bridge pickup on the other. | ||
| sscastro
Junior Username: sscastro Post Number: 14 Registered: 2-2005 |
Hi David I will be away for a couple of days, in Portugal, but I'll get back to this. Definitely there must be something wrong on the connections. If the shielding is effective to the pot attached to it, should be so to the second pot on the bass EQ. In the meantime I found the controls description in your previous link and now I understand it better. The headphone test, wasn't easy as I only use studio 600 ohm sets, but I was still able to hear something and both pick-ups are there. So one position is bridge pick-up on the Right side, the next is in the centre, or thereabouts, due to frequency differences, the next is neck pick-up on the Left and then silence. The 3 other positions ARE noisy, and it sounds like a lack of ground. I will investigate where its broken and maybe I will need to hard wire the pots which show no ground connections. Do you think it's a good idea? Sorry Slawie, for the time being I am not willing to sell the IN-2, and yes it is for 240V. I have another small power supply, which is definitely for 115V. I've never used it before because of that. | ||
| davehouck
Moderator Username: davehouck Post Number: 9769 Registered: 5-2002 |
Good; sounds like you're getting both pickups. No; I don't think you need to hard wire the pots if they are snug against the shielding. At this point, good quality pictures of the interior of the control cavity and of the selector switch may be helpful. | ||
| keith_h
Senior Member Username: keith_h Post Number: 1666 Registered: 2-2005 |
Have you tried performing the hum canceling procedure? Keith | ||
| gtrguy
Advanced Member Username: gtrguy Post Number: 315 Registered: 9-2004 |
Cool bass!!! I got one with 9 layers! | ||
| sscastro
Junior Username: sscastro Post Number: 15 Registered: 2-2005 |
Hi Dave thanks for your patience. Here is one of the pictures of the cavity. Still puzzles me why the top of the bass EQ pot chassis does not show being to ground. I mean, you test from the earth connection to the bottom top and it blips, as well as with the bridge pick-up switch, but there is no contact with the top EQ pot.  | ||
| sscastro
Junior Username: sscastro Post Number: 16 Registered: 2-2005 |
this is a closer look of the same.  | ||
| sscastro
Junior Username: sscastro Post Number: 17 Registered: 2-2005 |
these are switch connections on pins 10, 1 and 2  | ||
| sscastro
Junior Username: sscastro Post Number: 18 Registered: 2-2005 |
Switch connections 3, 4, 5 and 6. I'm sure the ground to the switch is lost too, as I found a little piece of rotten copper, painted aluminium, like the ones crossing the cavity. But as it was smashed I removed it.  | ||
| sscastro
Junior Username: sscastro Post Number: 19 Registered: 2-2005 |
Finally positions 8,9, 10 (I believe I've missed 7, but it's linked to 6 with no other connection. 4 and 5 are also linked, with 5 connecting across to 10. 2 and 3 are linked with pin 2 receiving brown wire. 1 and 10 are linked receiving black wire on pin 10. 8 and 9 are linked receiving grey wire on pin 8. the internal pin close to pin 3 receives violet wire, and the other pin close to pin 8 receives orange wire. These are the connections as they were when the original switch got broken.  | ||
| mica
Moderator Username: mica Post Number: 7011 Registered: 6-2000 |
For checking the ground, you sometimes have to scrape away some clear epoxy on the back of the pot to get contact to conductive metal. The switch is not a part we supply, as we use Grayhill rotary switches. That it rotates all round doesn't indicate there is a problem with the switch you have, as some switches are designed to operate that way. Also, many rotary switches are non-shorting, and you will hear clicks and pops when changing positions. Our pickup selector switch has 10 terminals. Your description matches normal operation for a mono cord and a stereo output - 2 positions will sound the same and the other positions will have no output. Let's work on the noise. When you hear the noise, turn the volume controls on the bass completely down - does that make it silent and without noise? Also, can you give any description of the noise? I mean, is it high frequency hiss or low frequency hum or some other sound? We'll keep conversing one step at a time until we figure out the noise issue (and I will probably move this over to Troubleshooting soon). | ||
| sscastro
Junior Username: sscastro Post Number: 20 Registered: 2-2005 |
Thanks Mica I will be back home on Monday and I will do all tests you propose. I don't remember any clicks when changing positions so I would guess this switch works fine. Regarding the pots, they do not seem to have any epoxy on top. Only some make contact and others don't. I would have imagined that a dual concentric pot like the EQ ones should have both chassis to ground, like the bridge pick-up does, but not the neck pick-up (I sometimes refer to as bass pick-up). thanks again. Regards | ||
| sscastro
Junior Username: sscastro Post Number: 21 Registered: 2-2005 |
Hi Mica today I tried some of your recommendations. Yes, turning both of the volumes down, will make the noise disappear. Both pick-ups seemed to have the same kind and amount of noise. It's definitely a ground noise. I tightened all the pots to the bass body and surely the bridge pick-up volume knob started making ground contact to the chassis of the pot. Then I picked a piece of stranded shield and got it into the screw hole of the main Switch, forcing ground contact with the switch plate. This piece of wire went down the body of the bass, inside a plastic sleeve and, after a hard work, I finally got it to solder to the chassis of both the EQ pots. After that I had the bridge pick-up silent and sounding good and the neck pick-up, noisier than ever. The neck EQ switch still does not make any contact with the ground. I was using the stereo jack with two 11k resistors. I will try to use the IN-2 tomorrow in the hope of finding some different results. Maybe I need to get ground independently from the common point on the stereo jack, to each one of the contacts: Switch, EQ switch and the EQ pot. Or as Dave suggested, maybe I need to repaint the cavity. Thanks for your patience and your help. Sergio | ||
| keith_h
Senior Member Username: keith_h Post Number: 1667 Registered: 2-2005 |
Sergio, You may have missed my post above. Have you tried the hum canceling procedure? It is here. The FAQ explains the procedure and why. Keith | ||
| sscastro
Junior Username: sscastro Post Number: 22 Registered: 2-2005 |
Hi Keith Yes I tried it, but the problem was indeed no sound from one of the pick-ups. I found since that the internal coaxial connectors are very fragile indeed and probably there was a contact problem. Right now both pick-ups sound fine with the IN-2 unit although there's not a very high output from the bass into an Apogee preamp mic input. After, I tried with the stereo jack in one instrument channel of theApogee and there's quite a lot more output, but a bit more noise also. Anyhow this noise seems to be inherent to the electronics. With the hum canceling procedure I got it a bit better. The gain of both pick-ups is somewhere in a mid position. I have to try the bass in a real situation now. There are still some odd ground links as I mentioned in my last post to Mica, so I probably need to spray the cavity with the conductive painting. | ||
| mica
Moderator Username: mica Post Number: 7012 Registered: 6-2000 |
I have to dash out and vote, so my answer is a little abbreviated, but unless there is a breach in the shield under one or more of the pots that is blocked from view, the shield looks intact - it's pure silver, and does not break down over time. When you say ground noise, can you try to describe it a little more? Is it 50Hz hum? If it's high-frequency or directional, there's only a little we can do about it remotely since the bass will be in need of an electronic upgrade. Replacing all three pickups will help in the absence of an upgrade (and is the first step in the upgrade actually). Do set the gain controls on the pickups where they give you the output you prefer - there is no impact on tone when you adjust them. The 1/4" jack is still wired in stereo? | ||
| sscastro
Junior Username: sscastro Post Number: 23 Registered: 2-2005 |
Hi Mica the noise was definitely like 50Hz hum, but as you may have noticed in my previous post, I found that most of the problem was in the neck pick-up coaxial connector and by gently squeezing it and re-connecting it again, the noise disappeared and the pick-up started sounding fine. Now there is still a bit of electronics noise, but only with the stereo to mono jack lead, with the 11k resistors. Using the IN-2 it sounds pretty clean. The screen is still soldered to the neck EQ bottom pot and doing contact with the rotary switch plate. best regards | ||
| sscastro
Junior Username: sscastro Post Number: 24 Registered: 2-2005 |
Hi I would like to thank Dave, Mica and Keith for all your great help. The bass is now working almost fine, with a little bit of electronics noise, which I believe to be inherent to this design. It's more noticeable using the jack output, then when using the IN-2. I still would like to give it an Alembic Logo on the peghead, if possible. It looks like it will soon be used for recording a few tracks. thanks again regards Sergio | ||
| davehouck
Moderator Username: davehouck Post Number: 9820 Registered: 5-2002 |
Sergio; glad it's working for you now. It's a beautiful bass. |
