The part number matches the datasheet. If they are 6.5 mm bushings then we are being sold something different under the wrong number.
Enjoy the benefits of a premium membership!
Upgrade Account
-
TalkBass has been independent since 1998. Add your voice.
Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
Join free Log in
Want zero display ads or expanded classifieds tools? Compare plans.
Look at the datasheet again. [Invalid or Expired Link Removed] Especially in the case of the 100K pot, the first pot that shows up on the sheet (RV16AF-10B6) is NOT what is being ordered. (This is what I thought I was getting when I ordered, as well...) The second pot down (RV16AF-20) is the one Mouser has on offer. The 10B6 piece of the part number is what I think specifies the 9.5 mm bushing, and searching for those on Mouser's web site brought no results... Also, the datasheet reference on each of the 3 different value pot data pages at Mouser references the exact same datasheet from Alpha. Someone may have taken a shortcut when setting these references up for the Mouser web site, or it may be all that Alpha has.
It's not your fault or mine, but it is misleading.
Sorry.
It's not your fault or mine, but it is misleading.
Sorry.
Passinwind
I know nothing.
- Dec 3, 2003
- 23,054
- 45,945
- Disclosures
- Designer/Toaster Tech @ Passinwind Electronics
I just use 500K "lefty" pots from Bourns or CTS instead of 1Meg. Sounds fine to me in the particular basses I've done that in. They're typically 24mm format though, for better or worse.
Last edited:
Good idea. B1M is also available in that style of pot fairly readily. I've heard a fair number of people being happy with a linear taper in this position. Both are a compromise on the original circuit, and both may work as well or better than the original C1M.
The last one I built I used a linear taper and it worked fine.
I can't remember the value but it was less than 1M, 250k sticks in my mind bu as always I could be wrong.
Building one of these right now actually. Thanks for making it simple. However, I think the mouser cart may be one cap short? I have four electrolytic: two 10uf and two 1uf. What am I missing?
Thanks for pointing that out. I've modified the shared basket - hopefully that works...
Not sure if you guys are still looking for pots but I’ve used these from MojoTone, at a little less than $5 each, when I built one of UncleFluffy’s boards:
A100K:
[Invalid or Expired Link Removed]
C1M:
[Invalid or Expired Link Removed]
A25K:
[Invalid or Expired Link Removed]
These have 3/8” bushings which are perfect for basses with rear routed cavities but will be too long for control plates, but it’s nothing an extra nut won’t fix.
A100K:
[Invalid or Expired Link Removed]
C1M:
[Invalid or Expired Link Removed]
A25K:
[Invalid or Expired Link Removed]
These have 3/8” bushings which are perfect for basses with rear routed cavities but will be too long for control plates, but it’s nothing an extra nut won’t fix.
Last edited:
Those look good. I got some Bourns pots and compromised for a linear pot for the treble control. I think it will be fine (possibly better) but if I don't like the taper I know I can grab one of these.
I just installed one of these and I was wondering if anyone else is experiencing what I think I’m dealing with: my bass control seems to cut but not boost? Like it only works to about half way up. Is this to do with the pot value? Anyone else notice this by chance?
Just double checked. Pretty sure it’s right. Middle lug and ccw. It is a detented pot, though I don’t see how that would make a difference.
something in the circuit is incorrect. swap the pots and see if it does the same thing. its rare to get a bad new pot
I’ve tested the pot with a dmm and it’s reading fine. Around 50 at the detent and close to 100k at full. Totally lost as to why it would cut but not boost.
Passinwind
I know nothing.
- Dec 3, 2003
- 23,054
- 45,945
- Disclosures
- Designer/Toaster Tech @ Passinwind Electronics
Yep I realized that late last night. I used it because i already had it and didn’t realize it would make such a difference. I can live with it for now as long as I know things are functioning properly. I’ll order a log with my next mouser order. Thanks.
Dylanthomaspals, I'm certainly not an electronics expert, but here's how I see it:
With this circuit design, the bass cut and boost are not linear and proportional, but many people really like it the way it is (that's why this is such a popular preamp). So, let's pretend that they are for practical purposes (in other words, people perceive the bass and treble tone as fairly neutral or "stingray-like" with the knobs halfway up, with cut to the left and boost to the right).
(In actuality the circuit is more complicated than that, as John East explains here: Stingray aftermarket 2 band pre
and here: 2 Band Stingray Preamp)
With the intended log pot, the pot turned down to zero would give a perceived bass cut, and with a linear pot, the pot turned down to zero would give the same bass cut.
With the intended log pot, the pot turned up all the way would give a bass boost, and with a linear pot, the pot turned up all the way would give the same bass boost.
With the intended log pot, the pot turned up half way would yield an amount of bass that might be perceived as neutral. But, since it's a log pot, in terms of resistance and the change in the circuit, its value is only 10% (or so) of the way between zero and the maximum. That is very different from the linear pot, which when turned up half way yields a value 50% of the way between zero and the maximum. So, if you indeed made the rest of the circuit correctly, then the linear pot turned down to zero is maximum bass cut, the linear pot turned up only 10% is the neutral tone (the tone that the log pot would yield turned up half way), and the range from above 10% to 100% is all boost.
I can see how you might perceive that the circuit doesn't boost since with the knob in the middle, you're already hearing a fairly boosted bass (which you might naturally incorrectly assume is neutral, since the pot is in the middle of its travel). But if you keep in mind that the 10% setting on your linear pot is really the neutral point, you ought to be able to get the exact same range of bass boost/cut (although it's very fiddly to dial in all of the cut in 10% of the knob travel, or find that neutral tone at right around 10% of the pot's travel).
To get an idea if the circuit really is boosting the bass or not, you could wire the pickup directly out passively, and record a bit. Then make a comparison recording with the preamp in the circuit and the treble set to its midpoint and the bass all the way up. If you hear much more bass on the active recording, then the preamp is probably functioning correctly. If you don't hear more bass on the active recording, then maybe you have a circuit problem.
Either way, do get the log pot.
With this circuit design, the bass cut and boost are not linear and proportional, but many people really like it the way it is (that's why this is such a popular preamp). So, let's pretend that they are for practical purposes (in other words, people perceive the bass and treble tone as fairly neutral or "stingray-like" with the knobs halfway up, with cut to the left and boost to the right).
(In actuality the circuit is more complicated than that, as John East explains here: Stingray aftermarket 2 band pre
and here: 2 Band Stingray Preamp)
With the intended log pot, the pot turned down to zero would give a perceived bass cut, and with a linear pot, the pot turned down to zero would give the same bass cut.
With the intended log pot, the pot turned up all the way would give a bass boost, and with a linear pot, the pot turned up all the way would give the same bass boost.
With the intended log pot, the pot turned up half way would yield an amount of bass that might be perceived as neutral. But, since it's a log pot, in terms of resistance and the change in the circuit, its value is only 10% (or so) of the way between zero and the maximum. That is very different from the linear pot, which when turned up half way yields a value 50% of the way between zero and the maximum. So, if you indeed made the rest of the circuit correctly, then the linear pot turned down to zero is maximum bass cut, the linear pot turned up only 10% is the neutral tone (the tone that the log pot would yield turned up half way), and the range from above 10% to 100% is all boost.
I can see how you might perceive that the circuit doesn't boost since with the knob in the middle, you're already hearing a fairly boosted bass (which you might naturally incorrectly assume is neutral, since the pot is in the middle of its travel). But if you keep in mind that the 10% setting on your linear pot is really the neutral point, you ought to be able to get the exact same range of bass boost/cut (although it's very fiddly to dial in all of the cut in 10% of the knob travel, or find that neutral tone at right around 10% of the pot's travel).
To get an idea if the circuit really is boosting the bass or not, you could wire the pickup directly out passively, and record a bit. Then make a comparison recording with the preamp in the circuit and the treble set to its midpoint and the bass all the way up. If you hear much more bass on the active recording, then the preamp is probably functioning correctly. If you don't hear more bass on the active recording, then maybe you have a circuit problem.
Either way, do get the log pot.
Hey guys,
I also tried to build one of these for my 'Ray and I guess I failed. I'm really not an expert when it comes to reading these schematics but I double checked it already and I'm pretty sure it's wired as it should - at least if I'm reading the diagram correctly!
So here's my problem: the volume knob doesn't seem to have any effect at all. I turn it all the way up, all the way down, everything in between - volume is always on and not decreasing a bit when turned down.
Treble pot: first of all, it may be wired in reverse as it cuts when turning it clockwise and vice versa. But there is no (for me at least) audible difference in the first ~90% of turning the pot. The last tiny bit then suddenly adds a lot of high end, zing and also hum.
Bass pot: same here, probably wired in reverse just like the treble pot. Now here, the first ~10% seem to do nothing, so rolled off the bass is cut all the way, then after a very short turn it boosts the bass to the moon! Basically it's the same as the treble pot just inverted, if you will.
Any ideas what's going on? Should I just rewire it completely? Is there a defective part? Like I said, I'm no expert at reading these diagrams, I'm not 100% sure the 9V, the input/output etc. are soldered to the correct ports - but I'm pretty sure...
Later this day, I will ask my father, as he's a electronic engineer, let's see if he can figure it out. Just wanted to ask you guys if any of these 'symptoms' sound familiar and you know where I'm wrong.
Thanks in advance!
I also tried to build one of these for my 'Ray and I guess I failed. I'm really not an expert when it comes to reading these schematics but I double checked it already and I'm pretty sure it's wired as it should - at least if I'm reading the diagram correctly!
So here's my problem: the volume knob doesn't seem to have any effect at all. I turn it all the way up, all the way down, everything in between - volume is always on and not decreasing a bit when turned down.
Treble pot: first of all, it may be wired in reverse as it cuts when turning it clockwise and vice versa. But there is no (for me at least) audible difference in the first ~90% of turning the pot. The last tiny bit then suddenly adds a lot of high end, zing and also hum.
Bass pot: same here, probably wired in reverse just like the treble pot. Now here, the first ~10% seem to do nothing, so rolled off the bass is cut all the way, then after a very short turn it boosts the bass to the moon! Basically it's the same as the treble pot just inverted, if you will.
Any ideas what's going on? Should I just rewire it completely? Is there a defective part? Like I said, I'm no expert at reading these diagrams, I'm not 100% sure the 9V, the input/output etc. are soldered to the correct ports - but I'm pretty sure...
Later this day, I will ask my father, as he's a electronic engineer, let's see if he can figure it out. Just wanted to ask you guys if any of these 'symptoms' sound familiar and you know where I'm wrong.
Thanks in advance!
Hi,
i just noticed something strange. We checked the plan and my wiring and it seems ok so far until to a certain point. My board has a different layout than the diagram suggests. I checked the OSH Park website and the picture of the product now even looks different than the product I received:
In my order history though, there's a picture of the board that just looks like the board I hold in my hands right now. So... has the board which I bought via this Link been changed/updated? The products site says it was uploaded in Feb '18 and shared on March '18, which really confuses me right now. Did OSH Park send me a wrong board?
i just noticed something strange. We checked the plan and my wiring and it seems ok so far until to a certain point. My board has a different layout than the diagram suggests. I checked the OSH Park website and the picture of the product now even looks different than the product I received:
In my order history though, there's a picture of the board that just looks like the board I hold in my hands right now. So... has the board which I bought via this Link been changed/updated? The products site says it was uploaded in Feb '18 and shared on March '18, which really confuses me right now. Did OSH Park send me a wrong board?
