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The John East preamp club

#581
Looking to buy a Uni-pre for my Heartfield bass. Ideally I'd go with the 4 knob far as functionality goes. Bit of roll-off on the high shelf sounds very useful. Unfortunately my bass currently has 3 pots and a switch that is too close to those pots to be drilled out for the 4th pot. It also limitsthe arrangement options for the circuit boards on the Uni-pre. I'm happy with putting a new hole in a bass that has long since paid for itself. But I'd like to know I'll be able to fit it all in B4 l I place my order.

What I would like to know is the sizes of the boards. I've spent some time looking on the site. But all I've found are technical specs. No dimensions. I was wondering if anyone on here might have that information easily available.

TIA for any help the good members can offer. I'll also email the company with my request. But I know there's often a quick answer on here so it seemed like a good place to start.
 
#582
Hey :) My luthier wired a uni-pre 4 in the bass he's building for me, and told me the volume pot does nothing in active mode (but works fine in passive).
Everything else seems to be working as expected (although the ribbon cable connecting the main volume PCB to the tone control was not properly connected, but easy fix).

Any idea, suggestion on what to check ? Would connecting the pickups the wrong way (hot <=> ground reversed) have this effect in active mode ?
We'll have to check the gain trim pots, but even at +12dB I don't suppose they would prevent the knob from doing its job.
Thanks a lot in advance :)

Tagging Mr @John East just in case :)

factory presets said:
Looking to buy a Uni-pre for my Heartfield bass. Ideally I'd go with the 4 knob far as functionality goes. Bit of roll-off on the high shelf sounds very useful. Unfortunately my bass currently has 3 pots and a switch that is too close to those pots to be drilled out for the 4th pot. It also limitsthe arrangement options for the circuit boards on the Uni-pre. I'm happy with putting a new hole in a bass that has long since paid for itself. But I'd like to know I'll be able to fit it all in B4 l I place my order.

What I would like to know is the sizes of the boards. I've spent some time looking on the site. But all I've found are technical specs. No dimensions. I was wondering if anyone on here might have that information easily available.

TIA for any help the good members can offer. I'll also email the company with my request. But I know there's often a quick answer on here so it seemed like a good place to start.
Click to expand...
Had the same question, what I did was to take the pictures from the website, and guesstimate the dimensions of the PCBs based on the dimensions of the knobs (which are available on the website). I then added a small error margin just to be safe. Hopefully you already got your answer though :thumbsup:
 
#583
XLunacy said:
Hey :) My luthier wired a uni-pre 4 in the bass he's building for me, and told me the volume pot does nothing in active mode (but works fine in passive).
Everything else seems to be working as expected (although the ribbon cable connecting the main volume PCB to the tone control was not properly connected, but easy fix).
Click to expand...

With the volume in active doing nothing, is there no sound or it's at max level no matter what the setting?

If there's no sound, please check that the RED JUMPER LINKS present, see pic:
RED JUMPER LINKS.jpg
 
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#584
John East said:
With the volume in active doing nothing, is there no sound or it's at max level no matter what the setting?

If there's no sound, please check that the RED JUMPER LINKS present, see pic:View attachment 4612449
Click to expand...
I think we should keep discussing this issue by email, but I just wanted to say that the fact that it took less than 1 hour and a half for the manufacturer to answer on this public forum is absolutely amazing :thumbsup:
I will re-post here when a solution is found.
 
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#586
XLunacy said:
I think we should keep discussing this issue by email, but I just wanted to say that the fact that it took less than 1 hour and a half for the manufacturer to answer on this public forum is absolutely amazing :thumbsup:
I will re-post here when a solution is found.
Click to expand...
Posting to say that J.East has been very helpful to solve the issue quickly (jumper indeed had to be moved). Just got the bass and I'm stoked, the preamp sounds phenomenal :hyper::hyper::hyper::hyper:A NBD thread is on the way
 
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#590
XLunacy said:
What are those for ?
Click to expand...
The springs are to maintain a ground connection to the knobs, especially the upper knobs on the stacks. As time goes on, the inner and outer shafts tend make and break contact as they are rotated, causing a scratchiness, you don't get with non-metallic knobs.

They are a custom made conical spring as we couldn't easily find something we could just buy in, directly. We need to include them on the website as an accessory. The material is phosphor bronze that is good for electrical contact.
 
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#591
Ordered a 3 Knob Uni yesterday for a Marusczyck 5 String with Delano HE P/MM pickups. I tried an Audere 4 band in it, and for some reason I am not getting the tone or punch that I want out of this bass. I think the Audere works great for other applications and pickups, but this is the 2nd time I tried one in a P/MM setup with the same results. Last time, I sold the bass thinking that it might be uncurable. Hoping the flexability of the John East Uni Pre cures this issue. It doesnt have a rear access cavity, but I think I can fit it under the pickguard.
 
#592
I been sporting a Uni-Pre 5 for over a year now, happy customer.

By coincidence, while organizing an ever growing mountain of bass parts etc., I found the manual for the Uni-Pre and saw that they have Tonecaps.

Does anyone have more information about these? What are they and what do the do/simulate.

I went to the East website but could not find any information about the Tonecaps and there are none being sold in the shop.

I know I have them in my Uni-Pre, would just love more information about them.
 
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#593
I've read that there's a piece that you can pull off to give a slight increase to the bass and treble side. Is that what you're talking about?
NordicBard said:
I been sporting a Uni-Pre 5 for over a year now, happy customer.
I just read the manual again. Not sure about the tone caps...my guess is that they give you time control in active and passive, rather than changeable values. East will probably come through and answer at some point

By coincidence, while organizing an ever growing mountain of bass parts etc., I found the manual for the Uni-Pre and saw that they have Tonecaps.

Does anyone have more information about these? What are they and what do the do/simulate.

I went to the East website but could not find any information about the Tonecaps and there are none being sold in the shop.

I know I have them in my Uni-Pre, would just love more information about them.
Click to expand...
 
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#594
xbud said:
It doesnt have a rear access cavity, but I think I can fit it under the pickguard.
Click to expand...
The circuit boards are 26mm top to bottom. With 10mm threaded shafts to attach the pickguard. I got mine with the boards up against the shielding on the floor of the rear mount cavity to get enough thread to screw the nut and washer on. But on a pickguard, that would have those stack knobs standing very high. With a nut under the pickguard, a 30mm rout should be a comfortable fit.

Or email Mr East for more expert advice. He tends to reply very quickly, time zones allowing.
 
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#595
Nope, talking about these:

WRcIHb.md.jpg


There is one for the Neck and one for the Bridge pickup.

If you Google them it is implied several places that it is meant that the user can change these to experiment with different tone rolloff frequencies.

But they are not listed anywhere on the website.
 
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#596
NordicBard said:
Nope, talking about these:

WRcIHb.md.jpg


There is one for the Neck and one for the Bridge pickup.

If you Google them it is implied several places that it is meant that the user can change these to experiment with different tone rolloff frequencies.

But they are not listed anywhere on the website.
Click to expand...

They just look like standard metallised polyester film capacitors which you can source from the likes of Digikey or RS. Any non-polarised capacitor will work, subject to available space and the legs fitting the jaws of the socket.
 
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#597
SteveCS said:
They just look like standard metallised polyester film capacitors which you can source from the likes of Digikey or RS. Any non-polarised capacitor will work, subject to available space and the legs fitting the jaws of the socket.
Click to expand...

Thanks! I Wonder what the rating is on the ones supplied with the Uni-Pre, will have to have a look later. Maybe East went for a 'One size fits all' solution.
 
#599
John East said:
Apologies that I didn't answer all of your questions.

Can you tell me if the tone caps are on the passive tone? (They would be on the latest units and sockets on the Vol/blend circuit board would be unused)

The types of caps are readily available from electronics suppliers, but we would normally supply them, our re-sellers wouldn't have them.
Click to expand...
Answering this message after a while since I got the bass in the meantime, and I wanted to make sure I understand what I'm seeing :

1651931584324_3.jpg
1651931584331_3.jpg


In RED what I think are the tone caps (they are caps according to the writing on them "1K63"), in BLUE where I think they should go.

Am I correct in assuming that where they currently are, they don't do anything, and that I should move them to the Volume / Blend PCB ? I tried to gently pull them but I did not succeed, so I'd like to make sure before I break anything.

Thanks for your help :)
 

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