Just to be 1000% sure, did you tightening the hex screw on the side of the knob? These symptoms describe exactly what happens when this screw gets loose over time.
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The John East preamp club
- Thread starter datsaxguy
- Start date
Hi team,
New to the channel after buying a JPBasses Plume having a custom 2 band John East preamp.
Hi all,
Pretty new to this forum but more importantly new to the JPBasses family !
Recently acquired this superb Plume 5 Koa from 2004.
Fantastic instrument.
This bass is 21 years old now and the treble control pot died on me.
This is a single pot (not dual concentric), the bass control having also its own pot.
From what I understood , this treble control should be Cut/Boost with a central detent, but it is freely rotating with no detent or any stop, meaning it goes over 360° with no effect at all.
I'd like to replace this pot to bring my bass to its original glory, but there is no indication of any type or value on the pot casing.
I tried to contact East for the last 2 or 3 weeks from the link on their website, with no luck yet (may be are they on vacation...).
Does anyone here knows something about this kind of pot, or can help me contacting John East ?
Thanks in advance.
Fred.
Can you take some pictures of the preamp, including some close up pictures of the back of the potentiometer in question?
Hi Xlunacy, you gave me hope that I missed that...
but no, removed the knob, it was well tightened.
Having the pot out of the cavity, it turn freely all around under my fingers.... so dead it is
@mcnach,
The pot reads B100K on the front of the casing, so I can order a linear 100k, but I do not know if it means to have a center detent.
Here is a picture of the electronic.
Attachments
As JPFerreira (Luthier of JPBasses) said:
"Just Try the E-pro BTB-01 (aka P-retro)
This preamp consists of the middle stacked pot from the J and U-retro preamps and I'm now fitting it as the standard pre for my basses."
Except that in my bass the pots are not stacked but individual
"Just Try the E-pro BTB-01 (aka P-retro)
This preamp consists of the middle stacked pot from the J and U-retro preamps and I'm now fitting it as the standard pre for my basses."
Except that in my bass the pots are not stacked but individual
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John has been unresponsive for the past few months. The last I heard from him was Feb 28. I'm worried.Hi team,
New to the channel after buying a JPBasses Plume having a custom 2 band John East preamp.
Hi all,
Pretty new to this forum but more importantly new to the JPBasses family !
Recently acquired this superb Plume 5 Koa from 2004.
Fantastic instrument.
This bass is 21 years old now and the treble control pot died on me.
This is a single pot (not dual concentric), the bass control having also its own pot.
From what I understood , this treble control should be Cut/Boost with a central detent, but it is freely rotating with no detent or any stop, meaning it goes over 360° with no effect at all.
I'd like to replace this pot to bring my bass to its original glory, but there is no indication of any type or value on the pot casing.
I tried to contact East for the last 2 or 3 weeks from the link on their website, with no luck yet (may be are they on vacation...).
Does anyone here knows something about this kind of pot, or can help me contacting John East ?
Thanks in advance.
Fred.
He sent me a few pots to replace the ones in my old stomp box SMTP-01, and I ended up not using all of them. I'm happy to send them over.
Last edited:
That's very nice to propose macribas, but I see you are in Texas, I live in France , that's a long way for a small pot.
What I really need to know is what is the exact type of pot used for the treble control.
I know now that it is a b100k, but does it have a center detent ?
Thanks again
Yes, John uses pots with a center detent for treble control.
Thanks a lot macribas,
I went thru John East website and JPBasses publication as well.
So yes, both Bass and treble pots have a center detent, treble because it is a Cut/boost, bass to have some indication (boost only)
Looked in the bass they are both b100k.
So I ordered 2 pots, b100k with center detent, to change both as the motion of the bass pot is a bit strange (but still working), remember that bass is 21 years old.
Did not find easily (price/delivery time) the Alpha pots that originaly were in the bass, but found Fender/CTS (same specs) at a decent price (about €7 each)
I'll let you know how it's going in a few days.
Thanks to all for your help.
I keep documenting this as it may help someone else in the futur
Fred.
I went thru John East website and JPBasses publication as well.
So yes, both Bass and treble pots have a center detent, treble because it is a Cut/boost, bass to have some indication (boost only)
Looked in the bass they are both b100k.
So I ordered 2 pots, b100k with center detent, to change both as the motion of the bass pot is a bit strange (but still working), remember that bass is 21 years old.
Did not find easily (price/delivery time) the Alpha pots that originaly were in the bass, but found Fender/CTS (same specs) at a decent price (about €7 each)
I'll let you know how it's going in a few days.
Thanks to all for your help.
I keep documenting this as it may help someone else in the futur
Fred.
Yes, please keep us posted on your progress!
Just stumbled across this - very useful... thank you!. In particular, The centre frequencies for the tone control bands was something I was guessing at. It looks like you've done some bode plots... interested in how you did that with the pickups? a coil with a frequency generator?. I was planning to do the same e.g. bode plots to work out the tone control centre frequencies with my signal generator and scope.
I've just received a new Uni-Pre 5 Knob preamp from John. There have been some significant improvements since the last one I bought.
Regards,
Alex
- Volume knob is now connected via a minature ribbon cable that appears soldered at both ends - I'm pleased to see that change as the previous three pin single row IDC connectors could be a little loose as there were only three pins holding it on at each end.
- Connection between the tone control board, balance board, mid module and passive tone module has changed to a much better connector (looks like a JST mini SMT) type that locks positively. I've previously had problems with the old ribbon cable design, so very happy to see this.
- All components are supplied pre-wired on a nice template, so it's very easy now to do a basic function test before installation (which is worthwhile, to get a 'known good' setup proved to work.
- New screen printed packaging and custom foam inserts - looks nice!.
Regards,
Alex
edwinhurwitz
Supporting Member
I installed a Uni Pre in my Modulus TBX 6. It sounds great, but the trim pots don't seem to be doing much. I'm getting a lot less gain with the bridge pickup and usually I can even these things out, but maxing out the bridge and cutting the neck pickup doesn't change the balance.
I have to say that in combination with Zen Blade pickups, the bass finally sounds like I had hoped. It's a 1991 and plays great.
I have to say that in combination with Zen Blade pickups, the bass finally sounds like I had hoped. It's a 1991 and plays great.
The trimpots will do nothing in passive mode. In active mode it works great, I added approximatively 4db to neck.
edwinhurwitz
Supporting Member
Strange mine match. Passive level and active, EQ flat very close, although I have the low jumper preset to slight bump.
Agree that the pre can be confusing to configure at first but after the deep dive of what it is doing, is worth it.
Agree that the pre can be confusing to configure at first but after the deep dive of what it is doing, is worth it.
edwinhurwitz
Supporting Member
OK, I took it all out, reinstalled it and rewired the pickups to it and now it seems to work fine. Weird.
Although I have to do it again, since I have the pan backwards as to where I want it.
Although I have to do it again, since I have the pan backwards as to where I want it.
If the pickup pan is working in the wrong direction, your connections on the balance pot module are the wrong way around. Keep the same position (top/bottom) and flip the connector 180 degrees at the balance control end.
edwinhurwitz
Supporting Member
I can unplug the pot from the board??? It appears to be soldered in and the bottom of the board is covered in some kind of epoxy or the like. I just have to reattach the pickup wires to the correct terminals or just live with it.
