Stingray aftermarket 2 band pre

[mcnach]

If I were to install a bypass switch, I've seen it recommended to replace the volume pot, and rather than a 10-25 K, use a 250-500 K one.
What is the reason for this, and what would be the effect if I left the original volume pot in place?

 

[SGD Lutherie]

If I were to install a bypass switch, I've seen it recommended to replace the volume pot, and rather than a 10-25 K, use a 250-500 K one.
What is the reason for this, and what would be the effect if I left the original volume pot in place?

The 25k volume control is for an active low impedance signal. If you tried to use that on a passive bass, you would have a muddy and quiet tone.This is because that value is too small for the high impedance pickups, and loads them down.

So you need a 250-500k pot. But the high value pots are too high for the preamp. It would probably work, but the taper might not be that great.

What you might want to try instead is remove the 25k pot from the preamp entirely. Instead, wire up a fixed 25k resistor from the output to ground. Now if you using it with something like a Jazz bass, you already have the volume controls on the input.

If you are using it for a single pickup bass, like an OLP, then wire up the volume before the preamp. When you bypass the preamp make sure the fixed 25k resistor is on the preamp side of the switch. You don't wan that in the circuit when you are passive.

 

[Dominic D]

If I were to install a bypass switch, I've seen it recommended to replace the volume pot, and rather than a 10-25 K, use a 250-500 K one.
What is the reason for this, and what would be the effect if I left the original volume pot in place?

CTS makes a stacked pot with a 25k and a 250k pot that I was planning on buying for this purpose. Just wire the 25k pot to the preamp as normal and wire the 250k as a passive volume after the active/passive switch.

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[SGD Lutherie]

CTS makes a stacked pot with a 25k and a 250k pot that I was planning on buying for this purpose. Just wire the 25k pot to the preamp as normal and wire the 250k as a passive volume after the active/passive switch.

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Yep, that's probably the best way to do it.

 

[mcnach]

.

This is not the way to do these things.
Please take it elsewhere.

 

[mcnach]

Thank you for the explanation and various suggestions.
That dual pot seems perfect. I think that is what I will use.
Thanks!

 

[Stealth]

CTS makes a stacked pot with a 25k and a 250k pot that I was planning on buying for this purpose. Just wire the 25k pot to the preamp as normal and wire the 250k as a passive volume after the active/passive switch.

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Thanks for the info, that'd be a pretty good solution.

 

[narud]

if any of you guys need one already assembled, im selling the one i bought from john kallas (johnk_10). im not using this one
http://www.talkbass.com/forum/f129/...tyle-pre-built-john-kallas-johnk_10-a-873515/

 

[kraigo]

Dorky question, and I'm posting from my phone where searches are painful: is the Music man two band boost only or boost/cut?

KO

 

[Dominic D]

Dorky question, and I'm posting from my phone where searches are painful: is the Music man two band boost only or boost/cut?

KO

They are boost/cut:

 

[lownoteBb]

If building this circuit as a stomp box to experiment with multiple passive basses-I'm still a little confused as to the volume control vs. impedance. Can I build it with the 25k vol pot on box without modding my basses?-Sorry I know this has been discussed but still a little unclear-Thanks

 

[SGD Lutherie]

If building this circuit as a stomp box to experiment with multiple passive basses-I'm still a little confused as to the volume control vs. impedance. Can I build it with the 25k vol pot on box without modding my basses?-Sorry I know this has been discussed but still a little unclear-Thanks

Yes, the 25k volume control is after the preamp, so it has nothing to do with the bass' volume control. It is like the volume control on any stomp box.

 

[tonymcbony]

So I bought the Danelectro concentric 100k/1M pot and it almost works perfect. I need to sort out the taper of the 1M pot as it sounds like it's linear; the treble basically turns on at the very end of the sweep and the rest of the sweep sounds like it's off.

The 100k bass works perfectly so I'm assuming it's log, whilst the treble seems to be acting like a linear pot. My plan is to chuck a 100k resistor from one of the lugs to the centre lug to give it a reverse log taper.

Has anyone had experience with this particular pot, and how did you deal with the treble?

 

[SGD Lutherie]

So I bought the Danelectro concentric 100k/1M pot and it almost works perfect. I need to sort out the taper of the 1M pot as it sounds like it's linear; the treble basically turns on at the very end of the sweep and the rest of the sweep sounds like it's off.

The 1M section is audio taper, thats why it works like that. Linear taper works fine. The 100K is linear taper, which works fine.

I use linear tapers for the 1M because it's easier to find than a reverse log, and they work better IMO.

 

[tonymcbony]

The 1M section is audio taper, thats why it works like that. Linear taper works fine. The 100K is linear taper, which is what it's supposed to be.

I use linear tapers for the 1M because it's easier to find than a reverse log, and they work better IMO.

I was hoping you'd chime in. I remember you mentioning something about using a Danelectro pot.

I thought that all the pots were meant to be linear? According to the schematic they were log pots? Invalid Link Removed

Got myself confused here?

 

[SGD Lutherie]

I was hoping you'd chime in. I remember you mentioning something about using a Danelectro pot.

I thought that all the pots were meant to be linear? According to the schematic they were log pots? Invalid Link Removed

Got myself confused here?

That diagram shows them as audio (log), and reverse audio (rev log) taper.

The volume and bass controls are audio taper, and the treble control is reverse audio.

The first couple of preamps I made had the reverse audio treble control, but it didn't match the pots I was using for the other two. So I tried a linear taper and that worked just as good, and I think the taper is smoother. You can also use linear for the bass control, which is why it works well with the Dano pots.

 

[tonymcbony]

Well, I chucked a 10k resistor across lugs of the 1M treble pot and now it works a bit better. It turns it from a 1M linear into a reverse log pot, which is exactly what we're after.

Here's the link for where I learned this. Scroll right to the bottom.

 

[tonymcbony]

All right folks, this is doing my head in. Where on earth can you get long threaded log pots for this?

I've bought a bunch of pots and none of them have long enough thread to get through the body and then plate of a Stingray HH.

I can source a long threaded bushing 25k log, and 1M linear pots from an allparts vendor but it's a real pain trying to get 1M reverse log or 100k log pots that are long enough. Any advice?

 

[johnk_10]

All right folks, this is doing my head in. Where on earth can you get long threaded log pots for this?

I've bought a bunch of pots and none of them have long enough thread to get through the body and then plate of a Stingray HH.

I can source a long threaded bushing 25k log, and 1M linear pots from an allparts vendor but it's a real pain trying to get 1M reverse log or 100k log pots that are long enough. Any advice?

bourns makes long shaft ones in 100K audio, and you can use a 1Meg linear one for the treble control:

http://www.bourns.com/data/global/pdfs/PDB241-GTR.pdf

 

[Rockprocess]

I've got one built up and installed in my Jaguar bass to replace the terrible stock preamp. It's obviously a 2 jazz pickup setup with the preamp between the pickups and the stock vol and tone controls.

I notice the treble control only works in the last tiny bit of the taper. Everything else is way too dark. I set the volume control on the preamp, a 25K trim pot on the board at unity gain. How can I get the treble more usable? Am I experiencing a loading issue with the jazz pickups and on/off switches? Any ideas? I'm using a reverse audio 1M treble pot and 100K log bass pot, everything else is also stock to the schematic.