| Author | Message | ||
| davidpetermarie
New Username: davidpetermarie Post Number: 1 Registered: 8-2007 |
hi, after a while of reading the forum and not finding the right information i am looking for i have to put that question in here. i bought the alembic filter on ebay a while ago and i really like to put it on my fender jazz. the bass is eqipped with passive sadowsky pickups and the wiring is volume, balance and passive filter. iŽd like to have the passive and the active filter in that bass, even is some woodwork is needed. so here`s my question: is it possible to get some instructions how to install it? thank`s a lot, david    (Message edited by davehouck on August 25, 2007) | ||
| fc_spoiler
Senior Member Username: fc_spoiler Post Number: 620 Registered: 5-2006 |
I could be wrong, but this looks like a preamp to me... (i.e. volume with gain trimpot) | ||
| davidpetermarie
New Username: davidpetermarie Post Number: 2 Registered: 8-2007 |
hi fc_spoiler, thanks for the comment. i`m sure it is a filter, because it was already in use in a blackbox for a test. unfortunately everything we tried to get it into the bass failed by now, that`s why i`m asking here. | ||
| grateful
Advanced Member Username: grateful Post Number: 231 Registered: 12-2004 |
Volume or filter, it is a preamp and is designed to run with an Alembic pickup and is unlikely to work well with anything else. Mark | ||
| terryc
Advanced Member Username: terryc Post Number: 240 Registered: 11-2004 |
davidpetermarie - I think grateful is right, Alembic pre amps & filters are designed to be used exclusively with Alembic p/ups, running them with other units would not work(impedance matching etc). That ground to the enclosed pot looks a bit suspect and all the cut wires too. All Alembic pre amps & filters(Activators as well) come pre wired and all you need to do is connect the molex connectors. Hope you haven't been ripped off | ||
| davidpetermarie
New Username: davidpetermarie Post Number: 3 Registered: 8-2007 |
thanks again for comment, as said berore the unit was tested in a blackbox. it was wired as an outbordpreamp. i could use it with any instrument just like a stompbox and never made any problems. i was really thrilled of that sound especially with my 78 fender. still hoping someone likes my idea david | ||
| keith_h
Senior Member Username: keith_h Post Number: 839 Registered: 2-2005 |
I think adding active controls to a Fender is a good idea. I have a custom built one in my 76 JB and since I used standard pickups I could always modify it to be active/passive. The problem here is the Alembic preamps/filters are set up in pairs. There is a filter and volume control. You are missing the volume control I believe. Also Alembic preamps are designed for low impedance pickups. Passive pickup are high impedance. I don't think the results of hooking the two up will be satisfactory. In addition the lower output of low impedance pickups usually precludes those from being used in a passive bass. I think you could go all of the way with Alembic pickups and the remaining electronics and have very good results. However I don't think your current plans are feasible. I could be off on some of my statements but I'm sure someone else will jump in to correct me. Keith | ||
| terryc
Advanced Member Username: terryc Post Number: 251 Registered: 11-2004 |
Keith h - you are right you cannot hook high impedance passive pickups with low impedance pre amps unless you have a buffer circuit to match them up. I guess it will work to a point but you may get distortion/loss of treble & bass or other undesirable sounds happening..maybe davehouck can chime in on this.. | ||
| davidpetermarie
New Username: davidpetermarie Post Number: 4 Registered: 8-2007 |
i`m glad the discussion is going on. thanx for taking it that serious! if there is a way to install the unit i`d be very happy... | ||
| davehouck
Moderator Username: davehouck Post Number: 5470 Registered: 5-2002 |
Terry, this is beyond my very limited knowledge base. I would have no idea how to wire this into a passive setup. | ||
| hieronymous
Intermediate Member Username: hieronymous Post Number: 179 Registered: 1-2005 |
If it were me, I would go with using it outboard, especially if you got that to work. Why limit it to just one bass? I much prefer to have my preamps last in my signal chain anyway. I hope you work something out! | ||
| dfung60
Advanced Member Username: dfung60 Post Number: 269 Registered: 5-2002 |
Actually, I hate to disagree with all you guys, but I think this is probably doable, especially if he's had it working in an external box. First off, don't worry about pickup impedances for the purpose of this discussion. The circuit is designed to work with Alembic pickups, but that shouldn't put you off. On a Series bass, the SC-1 pickups are wound with very little wire, so they have very low natural output, but I believe most of the other models are not radically different than normal passive levels (the pickups are not buffered before the panpot). Impedance matching is important for full frequency range, but the Alembic output isn't low impedance until after it has passed through *this* circuit, which *is* the buffering amp. I'm not sure exactly what this circuit is (the factory folks can easily identify it), but I think it's likely that the blue trimpot on the side is a level control. Now it might be a true gain control (modifies the amplification of the op-amp, but isn't in the signal path) or it may be a pre- or post-trimmer in the audio path. I'd also be willing to bet that the two pin molex is the signal in, plus and minus (this would have been fed from the pickup balance pot). The three pin molex is probably the output side, signal plus, ground, and +9V power, since these three lines would normally terminate in the same place, the output plug. Power ground would normally be the same as signal ground for a low-impedance unbalanced output. If you had access to the external box that this was in, it should be easy to verify. On a stock bass, I think the panpot would be a plain pot as would the master volume pot, so all the electronics are built on the tone pot like this. The folks at the factory should be able to provide the color code as should anybody that has a bass that has a circuit like this. David Fung | ||
| davehouck
Moderator Username: davehouck Post Number: 5486 Registered: 5-2002 |
David, please disagree all you want! I always enjoy reading your posts and find them very informative! | ||
| terryc
Advanced Member Username: terryc Post Number: 254 Registered: 11-2004 |
Davehouck - thought I would ask but looks like Mr Fung has put us all right here..guess it must be doable after all!! And I agree..his posts are a wealth of knowledge I guess this forum is the Alembic encyclopaedia | ||
| keith_h
Senior Member Username: keith_h Post Number: 844 Registered: 2-2005 |
As I said someone would jump in to correct me. Thanks David. Keith | ||
| 0vid
Member Username: 0vid Post Number: 99 Registered: 4-2003 |
Alembic Pickups and the associated electronics are designed to work with each other but they will work with other pickups and other preamps. I certainly have done this on more than one bass, and actually my FLY shaped bass I built sports two J activators and my own preamp. I was actually offered some J activators by a teenage kid who despised them, he was running them without ANY preamp in his bass and boosted his signal via some Korg Floorbox to his amp...how that happened I don't know (it was a Hamer cruise bass)....I just had to say "I'd take those defective pickups off you....!!!" He wanted to sell them with the bass but I'm lefty....I suppose I could have flogged it with other pickups but I have enough on my hands... Whether you'd like the results of pickup and preamp 'miscegenation', is really up to your ears. I have built preamps with or without EQ to work with Activators and AXYs. The Alembic on board preamp is high spec for sure but is nothing more than a clean preamplifier, it does not colour the tone. The filter however is something else altogether..... FYI ACGuitars in Scotland have worked with John East to build a drop in Filter based preamp that is not unlike the Alembic circuit. The price is also not unlike Alembic...but it is designed for the mass market so for ease of mind and ease of fit, if you want a filter type circuit, speak to Alan at AC guitars. I suppose they are googable. | ||
| davidpetermarie
New Username: davidpetermarie Post Number: 5 Registered: 8-2007 |
well, seems to be time to throw in some words again. thanx ovid for that interesting link - nice soundfiles, quite convincing and a real alternative for ideas like mine. but - i`m really pleased with the sadowsky pickups, they really fit into a lightweight old fender i think. so thank you for the offer, too. all in all i can see light at the end of the tunnel, with all this unvaluable information i got from you all. david |
