Pots with “Vintage” 30% Tapers? I Don’t Get It.

[MCT]

Hi guys,

I recently went down a pot rabbit hole (hehe), and am trying to resolve two contradictory pieces of information (and I apologize if this has been beaten to death). On one hand, every respectable source I see indicates that vintage Centralab pots had 10-20% tapers, yet so many of these aftermarket potentiometers that call themselves “vintage” boast a 30%, almost linear taper.

What gives? In what sense is this a “vintage” taper?

My potentiometer rabbit hole led me to the conclusion that the VIP pots and The Art Of Tone CTS 525k pots seem like the leading contenders- any one prefer one over the other for a TRUE vintage Centralab taper/tone? Or something else?

 

[robertoa1a]

I like things simple and always end up 50's wiring my LP's. Vintage taper slightly more than the 10% audio taprt, perhaps 20% has always been comfortable for me using .022 caps and vintage wind pickups (7.5 to 8.5 DC ohm range winding).

The purposes is to not have all of the control to be within 1 and 2, or 9 and 10, of the knob but spread out, or usable to you. If your playing and want to dial back... I like 10% to 20%. I assume the word vintage means a happy medium.
Whatever your gear responds to the best. When I go to 5, for example, I'm kind of expecting what i perceive as half. "vintage taper" has worked out.

 

[MCT]

I like things simple and always end up 50's wiring my LP's. Vintage taper slightly more than the 10% audio taprt, perhaps 20% has always been comfortable for me using .022 caps and vintage wind pickups (7.5 to 8.5 DC ohm range winding).

The purposes is to not have all of the control to be within 1 and 2, or 9 and 10, of the knob but spread out, or usable to you. If your playing and want to dial back... I like 10% to 20%. I assume the word vintage means a happy medium.
Whatever your gear responds to the best. When I go to 5, for example, I'm kind of expecting what i perceive as half. "vintage taper" has worked out.

Right, and I get that personal preference is ultimately what matters. My question is more about whether I’m missing something as to why many aftermarket pots that label themselves as “vintage taper” have a taper that’s the opposite of what I understand Centralabs’ taper to have been.

 

[MATTM]

To the best of my knowledge, the Centralabs used in old Gibson's were 30% audio taper.

 

[MCT]

To the best of my knowledge, the Centralabs used in old Gibson's were 30% audio taper.

Okay, so the question becomes what the taper on the classic Centralabs actually was. Most sources are pretty unanimous that it was a C2 taper which, according to this diagram from one of their manuals, is a 10% audio taper. This, to me, also fits with the anecdote that, above ~ 8-8.5 on the volume knob, the tone of the pickup (not just the volume) changed. Is there any reason to suggest this wasn’t the case?

 

[robertoa1a]

To the best of my knowledge, the Centralabs used in old Gibson's were 30% audio taper.

I thought that too but I thought 25% for some reason.
For the OP. I doubt you will be unhappy with what reputable sellers are selling as vintage taper. You are way thinking it.

 

[MCT]

I thought that too but I thought 25% for some reason.
For the OP. I doubt you will be unhappy with what reputable sellers are selling as vintage taper. You are way thinking it.

I have the tendency to become hyper-focused sometimes, but mostly with conceptual things, never with people. It’s helped me a lot in my professional life, while sparing me from being a total jerk (or at least, that’s what I tell myself).

But more importantly, I’m genuinely curious why there’s this disconnect. Both of these things (ie- Centralabs having a C2 10% audio taper, and companies claiming they have a “vintage” 30% taper, when implicitly referring to the same Centralab pots) can’t be right. Unless there’s something I’m missing.

 

[cooljuk]

Get used to conflicting specs and terminology in the music industry.

Fender still doesn't know the difference between a vibrato and a tremolo and Gibson hasn't figured out that the jack on your guitar is not an input.


Whatever taper your pots are, that taper will appear to change from rig to rig and as you turn up and down the compression / gain / distortion and your dynamic range is squashed.

I have a freezer bag full of old Centralabs and I could chart a few out for you (in fact, I already have) but then the question becomes if you are after the figures today or the figures 60 years ago, when they were made? ....or some time in the middle, when your favorite song was recorded? For sure, those old Centralab pots from Gibsons haven't aged gracefully! The values and physical rotation feel of them has certainly changed significantly.

 

[MCT]

Get used to conflicting specs and terminology in the music industry.

Fender still doesn't know the difference between a vibrato and a tremolo and Gibson hasn't figured out that the jack on your guitar is not an input.


Whatever taper your pots are, that taper will appear to change from rig to rig and as you turn up and down the compression / gain / distortion and your dynamic range is squashed.

I have a freezer bag full of old Centralabs and I could chart a few out for you (in fact, I already have) but then the question becomes if you are after the figures today or the figures 60 years ago, when they were made? ....or some time in the middle, when your favorite song was recorded? For sure, those old Centralab pots from Gibsons haven't aged gracefully! The values and physical rotation feel of them has certainly changed significantly.

James, you’re totally right. But from what I can tell, many of the Centralabs were fairly recent at the time of installation, and recordings came within 6-15 years (at least for the stuff I listen to), which leads me to believe (perhaps mistakenly) that they must’ve retained their tapers. Perhaps not their values, but their tapers. Though now that I think about it, I realize that I don’t know the physics behind taper aging.

 

[korus]

@cooljuk
If you measure several of them (eg 5 or 7) at full open and at half of rotation, and calculate the average of bith values you will get pretty accurately what the taper was regardless if value on some of the pots 'dropped' or 'jumped'.

And it will be either close to 10% or close to 30%. My bet is on 10%. Several years ago Glen Kuykendall (burst and Trainwreck amp) posted on the other forum what he measured on pots on his burst. It was 10%.

 

[MCT]

@cooljuk
If you measure several of them (eg 5 or 7) at full open and at half of rotation, and calculate the average of bith values you will get pretty accurately what the taper was regardless if value on some of the pots 'dropped' or 'jumped'.

And it will be either close to 10% or close to 30%. My bet is on 10%. Several years ago Glen Kuykendall (burst and Trainwreck amp) posted on the other forum what he measured on pots on his burst. It was 10%.

Which makes complete sense, seeing as how they were C2 tapers which, in Centralab speak, was a 10% audio taper.

So why the heck are most companies claiming 30% taper was “vintage?” It’s just wrong.

 

[cooljuk]

@cooljuk
If you measure several of them (eg 5 or 7) at full open and at half of rotation, and calculate the average of bith values you will get pretty accurately what the taper was regardless if value on some of the pots 'dropped' or 'jumped'.

And it will be either close to 10% or close to 30%. My bet is on 10%. Several years ago Glen Kuykendall (burst and Trainwreck amp) posted on the other forum what he measured on pots on his burst. It was 10%.

I've done this. The readings I took were at the outside legs, then from the wiper at multiple points along the path, including 50%, of course. I'll try to find my chart of readings and share them later when I'm sitting down with my files.

I can do it again with more samples now, also. I have several dozen Centralab 500k C2s. Some used, some NOS, many NOS in trim pot or stackable pot format that I can open up and swap the wafers into modern CTS housings (my personal preference, as you get a nice mechanical structure, with brass bushings and shaft, rear support, excellent wiper, etc., to go with the nice sounding wafer).

They read all over the place, from memory. You can forget that original 20% tolerance spec. Some are below 500k, some exceed 1M. I haven't personally found that use, time, or condition directly correlates to value. It seems similar to the carbon comp resistors in old electronics, where you might have 20 of the same brand/value in a given piece of gear where some have drifted high 200%+ and some have stayed dead-on, with seemingly no relation to the power or heat they handle in the circuit. On the other hand, just off memory, I do think the NOS C2s I have tended to read lower than most used ones I've measured so maybe there is some relation to the life they live. Dryer climates could be a factor or it could be that Im' just looking at a relatively small sample of a few hundred in the big picture of what's out there.

So, does the whole length of the trace drift evenly when they drift? I have no idea. Guess we can try to figure that out.

 

[cooljuk]

Here's four I measured with 1959 codes...

752 k 100% outer lugs
706 k 75%
676 k 50%
482 k 25%
1.13 Ohm 0%

911 k 100% outer lugs
875 k 75%
844 k 50%
595 k 25%
.95 Ohm 0%

725 k 100% outer lugs
689 k 75%
655 k 50%
446 k 25%
.9 Ohm 0%

792 k 100% outer lugs
757 k 75%
723 k 50%
518 k 25%
1.2 Ohm 0%


Don't lean too heavily on the 75% and 25% measurements being precise, as I was just using my eyes to turn the wiper to those points and they probably aren't too exact. Just interesting. The 0%, 50%, and 100% are dead-on, though.

 

[MCT]

Not what I’d expect C2 tapers to read.

 

[korus]

Here's four I measured with 1959 codes...

752 k 100% outer lugs
706 k 75%
676 k 50%
482 k 25%
1.13 Ohm 0%

911 k 100% outer lugs
875 k 75%
844 k 50%
595 k 25%
.95 Ohm 0%

725 k 100% outer lugs
689 k 75%
655 k 50%
446 k 25%
.9 Ohm 0%

792 k 100% outer lugs
757 k 75%
723 k 50%
518 k 25%
1.2 Ohm 0%


Don't lean too heavily on the 75% and 25% measurements being precise, as I was just using my eyes to turn the wiper to those points and they probably aren't too exact. Just interesting. The 0%, 50%, and 100% are dead-on, though.

(792-723)/792=8.71%
(725-655)/725=9.66%
(911-844)/911=7.35%
(752-676)/752=10.1%

So, clearly 10% taper it was/is.
'Correct' that 911 pot by 150 or 200 and
(761-694)/761=8.80%
(711-644)/711=9.42%

Absolute differences 100% vs 50% are:
69, 70, 67, 76.

it looks like 10% of 750k pot. Is there also a Centralab's lost ledger ... just kidding.

 

[cooljuk]

(792-723)/792=8.71%
(725-655)/725=9.66%
(911-844)/911=7.35%
(752-676)/752=10.1%

So, clearly 10% taper it was/is.

It is a small sample, all from within a narrow production window, and all drifted about 100% high, though. Best to not write anything down in stone yet. I can provide more and I'm sure others here could, too.

Over the next couple days, I'll try to remember to pull out a set that reads closer to original spec and measure those. I have some later ones form the early 60's, also.

Maybe some others who have some not installed can share, as well?

 

[korus]

There is a rather simple and obvious reason for the different effect the same regular 10% audio taper for volume pots works on original vs modern LPs. It is different tonal context - original tone vs modern tone - and that difference is what caused creation of custom (less steep curve) audio taper volume pots.

The effect of '50s wiring - cap/tone pot connected at output lug of volume - is (often verbally described as) gradually reducing mids in tone as volume pot is rolled off.

BUT, there is a huge difference original vs modern tone. Original tone has more mids and compression, and it lacks treble = clarity and punch for some. Modern tone has more treble and punch, but it lacks mids and fullness for some.

Obviously, original tone with more mids will suit BETTER for '50s wiring - there are more mids to begin with and to be removed by volume pot roll off. That is why original tone even when played 'through' volume pot with 10% taper has 'wider usuful range' - tone does not get too thin/too plinky even with volume pot rolled off low - think Jimmy Page on liverecordings playing his '59 neck PAF - 8.2k or 8.6k - on his #1 with neck volume pot as low as 5 or 3 sounds full, balanced and strong, almost like an acoustic guitar tone, strumming (several strings played) or single note (single string played) lines.

Modern tone simply does not have enough mids within itself BY DESIGN, DELIBERATELY for it to sound equally good = full, strong with 10% taper. Cause when mids are reduced by '50s wiring - tone very fast starts to sounds tiny, thin, like a banjo. Gibson USA 300k linear taper pots for volume pots are dead wrong overkill for the purpose - tone does not thin out too fast but taper is pretty much unusable. However, some a kind of middle ground - using audio taper pots with less steep curve - 20% taper (DiMarzio Custom pots) or 30% taper (RS Superpots) is better at keeping those insufficient/lacking mids of modern tone 'longer' (wider range before it thins out) in tone as vol is rolled off.

That is the reason for 'invention' and how custom audio taper (greater value than 10% taper = less steep curve = closer to linear taper) volume pots were born to be used in modern tone/guitars.

(Modern repros of originals have less mids than on originals due to metal hardware used, cause alloys used for modern repro hardware are much harder than on originals so modern repro hardware create mechanical resonance with treble = higher overtones and dampen mids =lower and mids overtones - which we hear as modern - treble rich, lacking mids, too punchy, too aggressive - tone. No manipulation of electric signal can compensate. Remove the cause - use the same alloys as on original hardware - and it will eradicate the unwanted effect = bring the original tone back. Simple.)

I guess this answers OP question.

 

[MCT]

There is a rather simple and obvious reason for the different effect the same regular 10% audio taper for volume pots works on original vs modern LPs. It is different tonal context - original tone vs modern tone - and that difference is what caused creation of custom (less steep curve) audio taper volume pots.

The effect of '50s wiring - cap/tone pot connected at output lug of volume - is (often verbally described as) gradually reducing mids in tone as volume pot is rolled off.

BUT, there is a huge difference original vs modern tone. Original tone has more mids and compression, and it lacks treble = clarity and punch for some. Modern tone has more treble and punch, but it lacks mids and fullness for some.

Obviously, original tone with more mids will suit BETTER for '50s wiring - there are more mids to begin with and to be removed by volume pot roll off. That is why original tone even when played 'through' volume pot with 10% taper has 'wider usuful range' - tone does not get too thin/too plinky even with volume pot rolled off low - think Jimmy Page on liverecordings playing his '59 neck PAF - 8.2k or 8.6k - on his #1 with neck volume pot as low as 5 or 3 sounds full, balanced and strong, almost like an acoustic guitar tone, strumming (several strings played) or single note (single string played) lines.

Modern tone simply does not have enough mids within itself BY DESIGN, DELIBERATELY for it to sound equally good = full, strong with 10% taper. Cause when mids are reduced by '50s wiring - tone very fast starts to sounds tiny, thin, like a banjo. Gibson USA 300k linear taper pots for volume pots are dead wrong overkill for the purpose - tone does not thin out too fast but taper is pretty much unusable. However, some a kind of middle ground - using audio taper pots with less steep curve - 20% taper (DiMarzio Custom pots) or 30% taper (RS Superpots) is better at keeping those insufficient/lacking mids of modern tone 'longer' (wider range before it thins out) in tone as vol is rolled off.

That is the reason for 'invention' and how custom audio taper (greater value than 10% taper = less steep curve = closer to linear taper) volume pots were born to be used in modern tone/guitars.

(Modern repros of originals have less mids than on originals due to metal hardware used, cause alloys used for modern repro hardware are much harder than on originals so modern repro hardware create mechanical resonance with treble = higher overtones and dampen mids =lower and mids overtones - which we hear as modern - treble rich, lacking mids, too punchy, too aggressive - tone. No manipulation of electric signal can compensate. Remove the cause - use the same alloys as on original hardware - and it will eradicate the unwanted effect = bring the original tone back. Simple.)

I guess this answers OP question.

So wait- let me get this straight- you think ‘50s wiring has more MIDS and modern wiring has more HIGHS? That’s exactly the opposite of my perception.

Also, your account doesn’t explain why these aftermarket 20-30% pots are marketed as “vintage” taper- your explanation makes it sound like they would be called “modern” pots (for “modern” wiring), no?

 

[korus]

So wait- let me get this straight- you think ‘50s wiring has more MIDS and modern wiring has more HIGHS? That’s exactly the opposite of my perception.

Also, your account doesn’t explain why these aftermarket 20-30% pots are marketed as “vintage” taper- your explanation makes it sound like they would be called “modern” pots (for “modern” wiring), no?

No.

I refer to factory stock Les Paul guitars made until end of 1960 as originals. Their tone is mids rich and I call it original tone.

All the Les Paul guitars made since 1968 are modern reproductions of originals. Unlike originals they have treble rich tone which I call modern tone. It lacks mids original tone has.

I am talking strictly '50s wiring.

More mids is why 10% taper works well with stock originals. Less mids in modern LPs that have modern tone causes 10% taper to not work well as on originals.

That is why the wiring at some point was changed to modern. That is why Gibson used 300k linear pots for volumes, and even 100k pots for tone pots. That is why bridge pickups started to get overwound. And many other things that try to put mids back in tone.

And that is why 20% or 30% custom audio taper volume pots works better with modern tone than regular 10% taper audio pots like Centralabs were when wiring on the guitar is '50s.

Because modern tone lack mids when compared to original tone. Cause when viring is '50s 20% or 30% taper pots sound more vintage on modern LPs than 10% taper pots. They keep mids better/'longer' within tone. 10% taper make both mids AND volume drop too fast. Because there are not enough mids in modern tone, intone of ALL LPs made after 1968 for 10% taper volume pots to work well.

Hence, 20% and 30% custom taper pots. They are not vintage. But they sound more vintage on modern LPs than vintage correct 10% taper. Hence, 'vintage taper' which is not vintage. Using 'vintage' sells them better.

This explanation seems too complicated for most and therefore omitted.

 

[MCT]

No.

I refer to factory stock Les Paul guitars made until end of 1960 as originals. Their tone is mids rich and I call it original tone.

All the Les Paul guitars made since 1968 are modern reproductions of originals. Unlike originals they have treble rich tone which I call modern tone. It lacks mids original tone has.

I am talking strictly '50s wiring.

More mids is why 10% taper works well with stock originals. Less mids in modern LPs that have modern tone causes 10% taper to not work well as on originals.

That is why the wiring at some point was changed to modern. That is why Gibson used 300k linear pots for volumes, and even 100k pots for tone pots. That is why bridge pickups started to get overwound. And many other things that try to put mids back in tone.

And that is why 20% or 30% custom audio taper volume pots works better with modern tone than regular 10% taper audio pots like Centralabs were when wiring on the guitar is '50s.

Because modern tone lack mids when compared to original tone. Cause when viring is '50s 20% or 30% taper pots sound more vintage on modern LPs than 10% taper pots. They keep mids better/'longer' within tone. 10% taper make both mids AND volume drop too fast. Because there are not enough mids in modern tone, intone of ALL LPs made after 1968 for 10% taper volume pots to work well.

Hence, 20% and 30% custom taper pots. They are not vintage. But they sound more vintage on modern LPs than vintage correct 10% taper. Hence, 'vintage taper' which is not vintage. Using 'vintage' sells them better.

This explanation seems too complicated for most and therefore omitted.

Maybe my hearing is just weird, but I hear PAFs (and modern PAF replicas) as brighter than subsequent modern overwound humbuckers, produced from the ‘70s till now.

With respect to the tapers, it’s certainly one explanation. I’d love to ask the relevant marketers their thinking about using these terms.