G
Guest
Guest
I've bought some 100K linear taper pots (as the seller stated), but they appeared to be W100K center dented pots. What does it mean?
Help Support GroupDIY Audio Forum:
Ptownkid
Well-known member
It's hard to say as there really is no standard, each company has their own naming system for their curve laws.
G
Guest
Guest
They are made by Alpha. I'll trace them later if nobody knows... Anyway, I need some for balance and EQ pots, so if they have S-looking curve it is fine, though I wanted to use them for a reverberation control...
W taper is 50% at mid point with plateau extending a few degrees either side of 50% rotation, roughly linear slope for +/- 20% from mid point, morphing to more logarithmic audio taper at bottom with symmetrical inverse curvature at top end. This curve is from Alps literature but Alpha probably copied that.
Clearly optimized for GEQs to deliver flat response when centered and usable adjustment feel for even short throw parts.
JR
Clearly optimized for GEQs to deliver flat response when centered and usable adjustment feel for even short throw parts.
JR
G
Guest
Guest
Thank you John;
it means they will go well for pan pots!
it means they will go well for pan pots!
thermionic
Well-known member
- Joined
- Jun 3, 2004
- Messages
- 1,671
I was told that Alpha use the same tooling as ALPS, with Alpha being a "splinter company" from ALPS. FWIW...
Justin
Justin
I've had dealings with Alps over the years and have also seen several samples from Alpha but never approved/bought any.
AFAIK Alpha was just a cheaper Taiwanese pot vendor who probably wanted to be viewed like Alps who by then was considered a "premium" higher end part vendor. Everybody old enough to remember when Alps were cheap pots raise your hand. :grin: Now Alpha is probably better than some of the small shoestring operations I’ve tested parts from out of Taiwan. I had buyers in purchasing who would get mad at me when I wouldn’t approve a new pot vendor after they crashed and burned in a production test.... I suspect the purchasing wonk was already counting his cost savings reward... There is such a thing as so cheap it doesn’t work, apparently.
I recall Alps moving manufacturing of some pot series to Brazil to manage costs in '80s//90s. Probably deep in Chinese mainland by now. Like everybody else.
JR
AFAIK Alpha was just a cheaper Taiwanese pot vendor who probably wanted to be viewed like Alps who by then was considered a "premium" higher end part vendor. Everybody old enough to remember when Alps were cheap pots raise your hand. :grin: Now Alpha is probably better than some of the small shoestring operations I’ve tested parts from out of Taiwan. I had buyers in purchasing who would get mad at me when I wouldn’t approve a new pot vendor after they crashed and burned in a production test.... I suspect the purchasing wonk was already counting his cost savings reward... There is such a thing as so cheap it doesn’t work, apparently.
I recall Alps moving manufacturing of some pot series to Brazil to manage costs in '80s//90s. Probably deep in Chinese mainland by now. Like everybody else.
JR
thermionic
Well-known member
- Joined
- Jun 3, 2004
- Messages
- 1,671
[quote author="PRR"]> remember when Alps were cheap pots raise your hand.
[/quote]
ALPS still are cheap, aren't they? Despite what resellers will tell you, none of the range is CP and they don't last too long in my experience, even the RK27. I wonder if there's a reason that the world's number 1 supplier of consumer pots doesn't use CP?
Forgive my OT jaunt:
A couple of weeks back, an associate wanted some ALPS RK40 pots. NOS sell for around 40 Euros each on Ebay. Not knowing the part was discontinued, I thought I'd give ALPS UK a bell... I'm thinking that an order of 100-odd might get the price down to below 20 Euros...
I get through to a "salesman"... "Hi, I'd like to obtain some RK40 pots", he says, "How many do you want?", I say, "100 or so - is that below your MOQ?" - Salesperson replies: "You can't speak to me unless you want to buy 50,000, you'll have to go to a distributor"...
I try to explain the RK40 is a pro-grade pot...to no avail... "I don’t care, I only deal with 50,000 minimum, call a distributor".
Do many OEMs purchase what would be a street value of 2million Euros worth of pots in one hit these days?
The salesman didn’t know the part was discontinued... I found that from the distributor.
Even at a fifth of the Ebay price, 400,000 Euros = over a quarter of a million quid , or over half a million dollars... I bet all the audio OEMs in Europe and the US buy half a million dollars worth of pots at a go...sure they do.
This salesman made me think of the Steve Coogan computer salesman, Gareth Cheeseman… The kind of guy who turns up at a sales conference and notes which salesmen have the half-leather interior in the car park…
Since Claro purchased several other brands (OTOH, Sfernice, Spectrol and remaining AB stock), the whole pot world got a lot smaller… Bourns don’t want to sell you less than a thousand and the stock Bourns values are pretty limited.
Forgive the rant!
Justin
[/quote]
ALPS still are cheap, aren't they? Despite what resellers will tell you, none of the range is CP and they don't last too long in my experience, even the RK27. I wonder if there's a reason that the world's number 1 supplier of consumer pots doesn't use CP?
Forgive my OT jaunt:
A couple of weeks back, an associate wanted some ALPS RK40 pots. NOS sell for around 40 Euros each on Ebay. Not knowing the part was discontinued, I thought I'd give ALPS UK a bell... I'm thinking that an order of 100-odd might get the price down to below 20 Euros...
I get through to a "salesman"... "Hi, I'd like to obtain some RK40 pots", he says, "How many do you want?", I say, "100 or so - is that below your MOQ?" - Salesperson replies: "You can't speak to me unless you want to buy 50,000, you'll have to go to a distributor"...
I try to explain the RK40 is a pro-grade pot...to no avail... "I don’t care, I only deal with 50,000 minimum, call a distributor".
Do many OEMs purchase what would be a street value of 2million Euros worth of pots in one hit these days?
The salesman didn’t know the part was discontinued... I found that from the distributor.
Even at a fifth of the Ebay price, 400,000 Euros = over a quarter of a million quid , or over half a million dollars... I bet all the audio OEMs in Europe and the US buy half a million dollars worth of pots at a go...sure they do.
This salesman made me think of the Steve Coogan computer salesman, Gareth Cheeseman… The kind of guy who turns up at a sales conference and notes which salesmen have the half-leather interior in the car park…
Since Claro purchased several other brands (OTOH, Sfernice, Spectrol and remaining AB stock), the whole pot world got a lot smaller… Bourns don’t want to sell you less than a thousand and the stock Bourns values are pretty limited.
Forgive the rant!
Justin
Back in the '70s I was allowed to buy some items in 1k minumum runs but even back then they preferred 5k per line item (and I still have some pots laying around from those days).
I suspect the economic order quantity is probably dollar weighted up at those more expensive series. A buy in requirement that large on such an expensive part would doom it to winning zero design ins.
JR
I suspect the economic order quantity is probably dollar weighted up at those more expensive series. A buy in requirement that large on such an expensive part would doom it to winning zero design ins.
JR
BYacey
Well-known member
When I started in the audio business Alps was like a buzzword equating to quality. After opening one up I wasn't really overly impressed.
[quote author="BYacey"]When I started in the audio business Alps was like a buzzword equating to quality. After opening one up I wasn't really overly impressed.[/quote]
Quality with respect to such components is perhaps a relative concept. Alps is mostly engineered to target high volume mass market applications so not gold plated but in comparison to some other brands, even old line American companies, I've seen differences that favor Alps for quality in similar parts. Two examples come to mind, one process and another design judgment.
The process related problem was from an American company (with factory in Taiwan). The resistive element on simple carbon element pots has it's bulk resistance set by first the general conductivity of the ink, and secondly when fixed or cured in an oven it shifts and locks on it's final resistance. There is some fine adjustment available by time spent in the fixing oven. Apparently this factory had messed up their wet resistance and had to over cook the elements to bring them in to 20% tolerance. The result was a brittle pot that cracked and failed in normal production handling. The most disturbing part about this incident is that when I approached that vendor to get their process straight they said we were too picky of a customer for them :roll:
The second example was design related. For an important product series we had decided to second source all of the key components which in this case included rotary pots. The specific component was an unusual EQ control with two resistive traces screened side by side on a common substrate and shunted by a wiper. This effectively gave us two pot sections in one with superior tracking. A design problem was later discovered in the American version of the part. They tried to get away with a stock 5 finger wiper to connect the two traces. Alps tooled up a custom wiper with two sets of 3 fingers for each trace. While perhaps difficult to visualize, the alignment of wiper fingers over two thin silkscreened traces on the substrate was marginal and in the course of production we encountered wiper intermittancies. The reason for multiple fingers is so some can bounce off surface irregularities and there will always be one or more touching. The five evenly spaced fingers to cover both tracks worked well enough to get the design approved pre production, but in full production a number of parts suffered scratchy noises when rotated.
This is a long way to say there are subtle quality differences that are not readily apparent, even perhaps to competing manufacturers. Alps has their technology well under control. FWIW Alps is not the only vendor making decent parts but there may be a little more to it than a casual inspection would reveal.
I have opened up lots of such parts and find the Alps well engineered and well built. I have seen lots of wannabes that looked vaguely similar but weren't, so don't assume all inexpensive series parts are the same.
JR
PS: Another factor which no doubt altered the perceived market position of Alps controls has been relative currency swings between Yen and dollar or western currencies over the years. I even recall 200+ Yen to $ exchange rates way back when, but not for a long time. So while they were the same parts they were no longer all that cheap.
Quality with respect to such components is perhaps a relative concept. Alps is mostly engineered to target high volume mass market applications so not gold plated but in comparison to some other brands, even old line American companies, I've seen differences that favor Alps for quality in similar parts. Two examples come to mind, one process and another design judgment.
The process related problem was from an American company (with factory in Taiwan). The resistive element on simple carbon element pots has it's bulk resistance set by first the general conductivity of the ink, and secondly when fixed or cured in an oven it shifts and locks on it's final resistance. There is some fine adjustment available by time spent in the fixing oven. Apparently this factory had messed up their wet resistance and had to over cook the elements to bring them in to 20% tolerance. The result was a brittle pot that cracked and failed in normal production handling. The most disturbing part about this incident is that when I approached that vendor to get their process straight they said we were too picky of a customer for them :roll:
The second example was design related. For an important product series we had decided to second source all of the key components which in this case included rotary pots. The specific component was an unusual EQ control with two resistive traces screened side by side on a common substrate and shunted by a wiper. This effectively gave us two pot sections in one with superior tracking. A design problem was later discovered in the American version of the part. They tried to get away with a stock 5 finger wiper to connect the two traces. Alps tooled up a custom wiper with two sets of 3 fingers for each trace. While perhaps difficult to visualize, the alignment of wiper fingers over two thin silkscreened traces on the substrate was marginal and in the course of production we encountered wiper intermittancies. The reason for multiple fingers is so some can bounce off surface irregularities and there will always be one or more touching. The five evenly spaced fingers to cover both tracks worked well enough to get the design approved pre production, but in full production a number of parts suffered scratchy noises when rotated.
This is a long way to say there are subtle quality differences that are not readily apparent, even perhaps to competing manufacturers. Alps has their technology well under control. FWIW Alps is not the only vendor making decent parts but there may be a little more to it than a casual inspection would reveal.
I have opened up lots of such parts and find the Alps well engineered and well built. I have seen lots of wannabes that looked vaguely similar but weren't, so don't assume all inexpensive series parts are the same.
JR
PS: Another factor which no doubt altered the perceived market position of Alps controls has been relative currency swings between Yen and dollar or western currencies over the years. I even recall 200+ Yen to $ exchange rates way back when, but not for a long time. So while they were the same parts they were no longer all that cheap.
Thanks, mr. Roberts!
thermionic
Well-known member
- Joined
- Jun 3, 2004
- Messages
- 1,671
Board software very glitchy for me today...
thermionic
Well-known member
- Joined
- Jun 3, 2004
- Messages
- 1,671
A couple of years back, I needed to source a stereo pot for an OEM for a hi-fi preamp. I obtained samples from several OEMs, and measured a few of each pot for stereo tracking tolerances.
Alps came second only to P+G (The RF15 - machined from a stainless billet - a work of art). I was shocked at how poor Clarostat 388s figured...very surprising, worst than many budget OEMs. Alpha's matching was ok, as was Sfernice. Bourns 51 was similar.
The only 2 brands that exceeded their quoted spec were P+G and ALPS.
If you open the pots up, Claro have a clever multi-finned wiper that ensures uber-quiet operation, it's just shame about the stereo tracking... Maybe I had a bad batch?
ALPS offer great value in terms of performance, but they don't last long at all in my experience. I've seen a lot of kit with the more expensive RK27s that need replacement...
I've yet to try AB modpots for stereo (I asked the group here a while back and got no feedback...). They aren't cheap and are NOS.
I like Bourns 51 and 91, but the feel can be inconsistent. They're super-quiet in operation and I use them more than any other pot. They last many times longer than any carbon in my experience.
BTW - John, Do you know how they match stereo pots for tolerance? I've seen pots that match well in tracking, but measure a lot different from end-to-end... I wonder how they match the gangs?
If you ever get a chance to visit the P+G factory, do it - the place is amazing. The factory is spotlessly clean and staff morale is high. Attention to detail is impressive. If you've been to the plant, you'll know why P+G's quality is so good, although you do pay for it!
Justin
Alps came second only to P+G (The RF15 - machined from a stainless billet - a work of art). I was shocked at how poor Clarostat 388s figured...very surprising, worst than many budget OEMs. Alpha's matching was ok, as was Sfernice. Bourns 51 was similar.
The only 2 brands that exceeded their quoted spec were P+G and ALPS.
If you open the pots up, Claro have a clever multi-finned wiper that ensures uber-quiet operation, it's just shame about the stereo tracking... Maybe I had a bad batch?
ALPS offer great value in terms of performance, but they don't last long at all in my experience. I've seen a lot of kit with the more expensive RK27s that need replacement...
I've yet to try AB modpots for stereo (I asked the group here a while back and got no feedback...). They aren't cheap and are NOS.
I like Bourns 51 and 91, but the feel can be inconsistent. They're super-quiet in operation and I use them more than any other pot. They last many times longer than any carbon in my experience.
BTW - John, Do you know how they match stereo pots for tolerance? I've seen pots that match well in tracking, but measure a lot different from end-to-end... I wonder how they match the gangs?
If you ever get a chance to visit the P+G factory, do it - the place is amazing. The factory is spotlessly clean and staff morale is high. Attention to detail is impressive. If you've been to the plant, you'll know why P+G's quality is so good, although you do pay for it!
Justin
It's been years since I messed with this, but indeed section to section tracking in multi section pots can be problematic. My worst experience with this was in an adjustable 4 pole L-R crossover. The 4 ganged alps pot even at their best tracking was still a potential issue for good Q integrity over full adjustment range. I was able to minimize bulk resistance and tracking errors at endpoints by the toplogy I used. I actually had a technician measure tracking at mid rotation and added a fixed resistor to tweak it in there too. This is yet one more thing that modern DSP does better.
From memory I recall a tracking spec something like 3dB at -40dB for dual volume controls which IMO is adequate for typical volume applications. It seems the stepped attenuator approach can be quite good for more yen.
JR
PS: Yes I recall using P&G faders on consoles back in '70s. My budget for faders at Peavey wasn't quite that rich, something like $40 ea back in the good old days, or motorized for only $375 ea.
but very nice parts.
From memory I recall a tracking spec something like 3dB at -40dB for dual volume controls which IMO is adequate for typical volume applications. It seems the stepped attenuator approach can be quite good for more yen.
JR
PS: Yes I recall using P&G faders on consoles back in '70s. My budget for faders at Peavey wasn't quite that rich, something like $40 ea back in the good old days, or motorized for only $375 ea.
but very nice parts.
G
Guest
Guest
What guys can you say about Song-Huei? Piher? Piher in catalogs clearly states matching "available upon request".
I don't recognize Song-Huei.
I've used Piher trimpots but their panel controls seemed to be little more than trimpots with shafts. This observation was formed years ago so they have probably changed since I last looked at them.
JR
I've used Piher trimpots but their panel controls seemed to be little more than trimpots with shafts. This observation was formed years ago so they have probably changed since I last looked at them.
JR
