| Joe Rasmussen |
Here is the photo of the "Silver-Carbon" pot that I've mentioned from time to time. This is clearly different from the Panasonic (supposedly also S-C) available from Thel in Germany and others:
This is the only pot I know that sounds uncoloured to me. The only pot I know that can stand comparison to a pair of resistors making up a "static" pot. And yes, it's tiny and soldering needs to be up to the job. Please note, it's not a quarter inch shaft, it requires a standard spline knob.
Here is my earlier post which describes the static resistor test that can be repeated with all pots:
Please read: http://www.diyaudio.com/forums/show...4156#post454156
Now Peter Daniel was dissapointed with the Panasonic S-C pot. It could be the lack of character (neutrality?) it may have if it sounds the same as mine? Hope Peter doesn't mind me saying that. One has to make allowance that some may not like it? Maybe they wouldn't like the DACT or similarly? Or perhaps my pot (I hope you don't mind me calling it that) is in fact that much better than the Panasonic? I just don't know.
Maybe somebody should get their hands on a Panasonic and do the same static resistor test, it's not a difficult one to do (and can be done with any pot). And if the Panasonic is up to the job, then some will like it and others will not.
The beauty of the static resistor test is that you have a real reference, it takes out the 'taste' factor and forces you to make an objective assessment/judgment. Try it, set it up and do it to a series of pots, this is what DIY is all about, then report back the findings.
So there you have it, a challenge that anybody can participate in, only basic equipment and your ears are required.
Joe R.
PS:For the photographic bums like myself, the above photo was with the latest Canon Pro-1 Series, 8 MegaPixel Digital Camera |
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| Peter Daniel |
Static resistor test (a pair of resistors forming a voltage devider) is only good if resistors have no sonic signature. I yet, didn't find such resistors.
For the record, I compared Panasonic pot against Vishay/Holco static resistor setup, and Panasonic was not comparable. |
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| Joe Rasmussen |
| quote: | Originally posted by Peter Daniel
Static resistor test (a pair of resistors forming a voltage devider) is only good if resistors have no signature. I yet, didn't find such resistors.
For the record, I compared Panasonic pot against Vishay/Holco static resistor setup, and Panasonic was not comparable. |
OK, maybe you're right re Panasonic. I used Beyschlag MF and compared to them any conductive plastic was far more colured. But the levels has to be within 0.1dB of each other, measured on the speaker terminals, switchable so that audio memory doesn't fail. That is the only way to conduct this test.
(BTW, this is also a useful way to test amps.)
If the levels are not matched precisely, the test will tend to favour the louder. I did another 'blind level reference test' where I increased by 0.6dB and my unware listener said this was definitely more 'transparent' and better. It wasn't, it was the exact same gear.
Joe R. |
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| Peter Daniel |
Nevertherless, Panasonic is a really nice pot. It does not posses the brightness that some Nobels have and sounds rather sweet. However, I was missing the last word in transparency, the discreet attenuator exhibits. I can suspect that Panasonic will appeal to tube enthusiasts;)
Testing a pot, like anything else in audio, greatly depends on the rest of a setup, more specificaly what is before the pot and what comes after. |
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| BlackDog |
| quote: | Originally posted by Joe Rasmussen
[B]Here is the photo of the "Silver-Carbon" pot that I've mentioned from time to time. This is clearly different from the Panasonic (supposedly also S-C) available from Thel in Germany and others:
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Joe,
Forgive me if I'm totally off track but that pot looks suspicously similar to what can be bought from Jaycar in NZ (you have them in Aus too!) for NZ$7.00 -- that's approx US$3.50 for the dual gang version.
I think I have one at home somewhere..
here's the link to Jaycar pot.
Maybe I'm wrong. Does yours have any identifying marks on it?
SteveM |
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| rdf |
I almost hate to ask, but has anyone tried using linear wirewound ten-turns? They've been in my passive for almost a decade now and I've never felt the need to swap them out. With ten turns the linear aspect is no big deal, and I do like the fact that the audio never jumps from metal to plastic (or carbon) to metal.
Just wondering about the experiences of others. |
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| jamesjung21 |
| quote: | Joe,
Forgive me if I'm totally off track but that pot looks suspicously similar to what can be bought from Jaycar in NZ (you have them in Aus too!) for NZ$7.00 -- that's approx US$3.50 for the dual gang version.
I think I have one at home somewhere..
here's the link to Jaycar pot.
Maybe I'm wrong. Does yours have any identifying marks on it?
SteveM |
Yeah,
I was wondering about that too...:rolleyes:
Joe, could you please let me know what it says at the back of the pot?
Cheers,
JayJay |
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| mrlots2do |
| quote: | Originally posted by BlackDog
Forgive me if I'm totally off track but that pot looks suspicously similar to what can be bought from Jaycar in NZ (you have them in Aus too!) for NZ$7.00 -- that's approx US$3.50 for the dual gang version.
SteveM |
I'm interested in dual gang and multi gang versions $USD. How much to ship to US? Anyone going to organize a group buy? If not, who sells them in the US? |
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| phs |
jaycar pots are definite cheap imitations, although if someone were willing id love to know how much difference there ACTUALLY is.
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| mozfet |
OK where do I get some to try???
Mozfet |
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| Joe Rasmussen |
| quote: | Originally posted by Peter Daniel
Nevertherless, Panasonic is a really nice pot... I was missing the last word in transparency, the discreet attenuator exhibits...
Testing a pot, like anything else in audio, greatly depends on the rest of a setup, more specificaly what is before the pot and what comes after. |
For sure. I like Beyschlags because I have to keep a very large number and values in hand, got a $1000 plus worth. I am not saying that selective use of other more exotic types will not improve sound (oops, I just used a double-negative - I gotta watch my grammar :smash: ).
I like the DACT asused in my RTP Reference Preamp (a VSEI design), and although not cheap, they are very good for the money. I can justify them is a $20.000+ preamp, no doubt.
But what is the best Pot?
That is in some ways a more exciting question, as Carlos indeed said on another thread. Real world affordability is a worthwhile quest.
Joe R. |
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| carlosfm |
Exciting.:D
Oh yes.:nod:
And cheap!
And small!
I like it.:)
Maby there's a place in Europe where to buy them?:bawling: |
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| falcott |
Hang on, I'm not missing something here, am I? Joe, are you saying that your favourite pot is available from Jaycar? I like decent audio AND cheap price!
I have a couple of Alpha metalcased 50k log pots I was thinking of using. I wonder if they are up to the same standards as their (your?) little plastic jobs?
I was just reading somewhere that Alpha makes 7,000,000 pots per month! |
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| phs |
hrm i guess i am wrong, i always assumed because of their price (few bucks AU) that they were substandard.
so in circuits where pots are preferred i am assuming that they have your full approval Joe? |
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| carlosfm |
| quote: | Originally posted by phs
hrm i guess i am wrong, i always assumed because of their price (few bucks AU) that they were substandard. |
It's not because it's cheap that it has to be bad.
It's just not a "fancy" brand.
People like to buy expensive...:rolleyes:
Some chips are also just a few bucks and give very good results.;)
This forum here is about them.:D |
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| Joe Rasmussen |
| quote: | Originally posted by carlosfm
Exciting.:D
Oh yes.:nod:
And cheap!
And small!
I like it.:)
Maby there's a place in Europe where to buy them?:bawling: |
I like it too.
So now my big, or should I say little secret is out. This pot is really tiny. It is a "9mm" class pot.
Strange enough I cannot find this exact one on Alpha's website - so I wonder if Jaycar picked up a big stash of these made OEM for another manufacturer/supplier?
I should have known that my secret would come out with that photo, but as Solomon said, "spread a little on water and some of it will come back..." - I suppose he meant goodwill and a bit more...?
I am quite sure Jaycar will accept overseas orders. And at the price, even shipping costs are acceptable just to try one. So maybe we can keep this thread going as others start listening to them. I use the 50K Log and that is the link I have shown. Channel balance is no worse than 0.5dB and often better, on the samples I have measured. Hope that will stay.
Oh, I must confess, I have a little history with Jaycar. Quite a few years ago I did some consultancy work for Gary Johnston, owner of Jaycar. I measured Taiwanese/Chinese speakers/drivers to find the best of the batch of samples, my work was later incorporated as comments, T-S values, recommended box types and tuning etc in Jaycar Catalogues. In those days very few computer systems for measuring T-S Parameters were available (unlike today - I now use ClioWin) that I had to write the software myself (it helps to live in the same town as A.N.Thiele).
| quote: | Originally posted by phs
hrm i guess i am wrong, i always assumed because of their price (few bucks AU) that they were substandard.
so in circuits where pots are preferred i am assuming that they have your full approval Joe? |
They are better than any conductive plastics that I know about - the Alps (Blue and Black) and the chunky Noble, Allen-Bradley Mod-Pots and Bournes - in terms of colouration and tonal neutrality. That is my opinion.
So what do I do if I now get a whole bunch of opposing views in the near future? Maybe find a hole to hide in. :warped:
Joe R. |
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| jamesjung21 |
NICE!!!:D
Because Jaycar is less than 50M away from my school:cool:
Have a look at this quotation from Jaycar:
"These pots are rapidly becoming the industry standard for miniaturised audio, digital and telecommunications equipment."
If anybody needs this pot in a small quantity, I can help you to get some...
I can probably send'em in small packets at my local post shop...
But I don't want hundreds of people asking me to help! I can just help a few people, so that they can try it without having much trouble...
Just contact me via : sendtojamesj@hotmail.com if you need help.
Cheers,;)
James Jung |
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| carlosfm |
Mouser sells Alpha pots:
http://www.mouser.com/taiwanalpha/
Maby they have or can get that specific pot.
Joe, is there a reference number or something on those pots? |
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| phs |
mmm very interesting revelation,
personally i have only used them in a LM1875 circuit for a friend so i never really benefitted from first hand experience, but after an endorsement from a Mr Rasmussen i will be using these more often *tips hat* :) |
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| falcott |
Thanks Joe!
Now, how the hell do I make custom knobs for these things??? :confused: Probably have to buy cheap plastic knobs, knock the centre out and press it into what I want to use... :smash: |
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| Variac |
Electric guitar knobs work on standard splined shafts.
Hey, you could have dice shaped knobs on your preamp-or skulls!!
Seriously , they do make some nice guitar/amp knobs....
I like the ones that are knurled chrome cylinders.
Hmmmm how about Fender knobs on a sunburst maple wood panel... |
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| carlosfm |
| quote: | Originally posted by Variac
Hmmmm how about Fender knobs on a sunburst maple wood panel... |
I like the retro style of Marshall amps.
Those knobs are :cool:. |
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| tiroth |
| Mouser has a 9mm Taiwan Alpha series that look like these pots but they don't have manufacturer part numbers. Anyone tried calling? |
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| wrenchone |
| From what I can see, the 9mm Alpha pots stocked by Mouser are all singles. They do have ganged 12mm units in both linear and audio taper, so you can try the quasi audio taper shunt resistor hack if you don't trust the tracking of the ganged audio taper pots. I have no idea if their ganged 12mm and larger pots sound as good as the 9mm ones, but they're pretty cheap, so it won't cost you a lot to find out either way... |
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| thomas997 |
I have asked Alpha about this and they sent me this picture.
They look fairly similar to me.
Minimum order quantity is 1000 though. |
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| KT |
Anyone do a listening test on these yet?
Inquiring minds (and ears) want to know!
Thanks,
KT |
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| Peter Daniel |
I received them yesterday, listened only briefly, but initial findings show that they are indeed pretty neutral and quite detailed.
Will follow up later with more listening impressions.
They are very tiny too;) |
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| carlosfm |
Where did you buy them, Peter?
$$$?
No channel imbalance at low volume?
Cheap?
Neutral?
Detailed?
I'm exxxxxxxcited!!!:bawling: |
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| Peter Daniel |
One of the members (from New Zeland) was offering sending them to interested parties, so I jumped on his offer.
I can surely say that for the price you can't go wrong with this pot. I also like the small size as the signal path is shorter ;)
Will do more listening tests today and report back. |
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| Cappy |
Peter,
A little bird told me that you had a PEC (Precision Electronic) pot you were going to try also.
I would be interested in any comparison you can make between the two pots as I am currently using (and liking) the PEC. |
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| ofb |
does anyone have experience with the discussed pots and this panasonic?
panasonic EVJ-C20F02D54, datasheet , digi# P2U4503, $2.66 US.
a little while ago the opinion in the headamp crowd was there really wasn't anything to choose between it and the expensive alps blue. i'm curious where it fits with the experience of the group here. |
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| KT |
Peter,
I'm sure you know we're all interested in your long-term listening impressions. Hope these are the giant-killers they promise to be.
I also ordered some of these pots to try out but don't have a gainclone ready to put them in at the moment. So I haven't listened, yet.
I ordered mine directly from the Jaycar website. They arrived stateside with no problems. Seems to me this is the most direct way of purchasing these.
Hope others will have a chance to try these out and post their impressions.
Thanks,
KT |
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| ofb |
EDIT: i just realized my post was unclear. it could be read to mean the pana EVJ was considered equivalent to the alps blue, which would be crazy talk.
i meant only that they'd found nothing cheaper than the alps that was better than the little EVJ; if you wanted better then you should go straight to the blue. sorry for the confusion. |
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| wrenchone |
| I'm curious to hear if anyone has listened to a cermet pot, like from Bourns or Spectrol/Vishay,and how they would compare to the lot mentioned so far. I'm considereing volume and balance controls for a new preamp, and the variety is overwhelming, to say the least. The preamp will be arranged so that aux inputs see the pot first through a coupling cap, followed by a line level buffer. |
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| lazyfly |
I've used a few of these. Hell they're the only decent quality pot here unless you go to RS or the like.
I can't compare them to anything but cheapy pots and they're certainly much better. Low level channel seperation is tighter and they weren't as muddy sounding.
Cheap at $5.50 AU too.
*edit: Here's one I destroyed earlier, actually I killed the shaft ;)
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| Steve Eddy |
| quote: | Originally posted by wrenchone
I'm curious to hear if anyone has listened to a cermet pot, like from Bourns or Spectrol/Vishay,and how they would compare to the lot mentioned so far. |
For me, I've found cermets to be the least preferred. But don't let that stop you. If you don't mind spending a few bucks, I'd recommend trying several different ones and decide for yourself what sounds best to you.
se |
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| Steve Eddy |
Here's a PEC I dissected some time ago.
The wiper, unlike most other pots which use some sort of stamped spring metal, is that little back slug of carbon at the bottom in the second row from the left. It seats in the piece of molded plastic just above it and it floats in the two holes in the spring steel wafer attached to the shaft.
se |
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| Coolin |
| quote: | Originally posted by wrenchone
I'm curious to hear if anyone has listened to a cermet pot, like from Bourns or Spectrol/Vishay,and how they would compare to the lot mentioned so far. I'm considereing volume and balance controls for a new preamp, and the variety is overwhelming, to say the least. The preamp will be arranged so that aux inputs see the pot first through a coupling cap, followed by a line level buffer. |
Im using a cermet Vishay P11 and think they are amazing. Havent had any pots in this thread to compare it to though.
Its also available in more channels.
Im still looking for alternatives that have up to 6 channels though. |
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| carlosfm |
I received some Alpha pots from Australia.:cool:
Three 50k dual log pots and two 10k dual logs.
They are really small, cute.:D
Smooth operators, absolutely no noise, beautiful.
Measuring in ohms between input and ground they have little difference between channels (specially for the price they cost).
Actually, on one of the 50k pots I measure exactly 47.6k on both tracks.:eek:
Gotta try them one of these days.:cool: |
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| TaaJ |
| quote: | Originally posted by carlosfm
I received some Alpha pots from Australia.:cool:
Three 50k dual log pots and two 10k dual logs.
They are really small, cute.:D
Smooth operators, absolutely no noise, beautiful.
Measuring in ohms between input and ground they have little difference between channels (specially for the price they cost).
Actually, on one of the 50k pots I measure exactly 47.6k on both tracks.:eek:
Gotta try them one of these days.:cool: |
Would they be suitable to hook right into Brians boards or would you recommend a series resistor? And if so what value? (I'm going to use a 50k Log)
I wont be using a buffer or snything. |
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| carlosfm |
On that amp, without an input buffer, you have 22k from NI to ground, at the input.
Right?
50k log would not be the ideal.
Big series resistors should not be used.
22k or 25k log would be fine, removing that resistor.
Or try the 50k log pot without the 22k resistor and check DC-offset on the output.
Instead of removing the 22k resistor, you can change it for a much higher value, like 220~330k. |
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| Peter Daniel |
| quote: | Originally posted by TaaJ
Would they be suitable to hook right into Brians boards or would you recommend a series resistor? And if so what value? (I'm going to use a 50k Log)
I wont be using a buffer or snything. |
There is no problem connecting those pots (50k) to Brian's board. I did that and it works perfectly well, providing good control range. I would not recommend removing 22k shunt resistor. It's there for a reason (to limit DC offset) and even with 50k pot it works fine. Additional influence is sonically and if you are using premium kit, a Caddock there will improve the sound of almost any pot. |
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| carlosfm |
Peter, that resistor will change the scale of the pot, it will attenuate until some level.
May not be a problem for some people.
The 22k to ground is for DC-offset optimization, but when you put a pot behind it there's some issues.
That configuration is fine for a power amp.
EDIT:
That resistor has influence on the sound of the amp.
Instead of attenuating, my suggestion of using a 22k~25k log pot with a 220~330k to ground will have much less influence on the sound of the amp, even with "normal" resistors.
IMHO. |
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| Peter Daniel |
| As I said, 50k pots (Nobel, Alpha, Panasonic) work perfectly well with 22k shunt resistor, and after using that configuration for 2 years ( on Amp-1) I don't feel like changing anythig ;) |
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| carlosfm |
I'm not telling you to change anything.:dodgy:
It's your amp, your ears, your clients.
I gave my oppinion. |
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| Peter Daniel |
| quote: | Originally posted by carlosfm
I gave my oppinion. |
Well, giving an opinion on something you didn't try may be misleading. Here's a quote from a review of the amp with 50k pot (and 22k shunt resistor):
| quote: | | The Noble attenuators' initially shallow taper and precisely mapped stepping. Not only was I never shy of proper adjustment options for the desired volume -- a common complaint with stepped attenuators -- I could open the pots to 11 o'clock on my 103dB Avantgarde horns to obtain regular output levels. Looking at the AMP-1's very high gain of 30dB, this suggested that the majority of gain comes on very gradually and late. This makes the controls active and potent well past high noon to broaden useful real-world range. |
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| maxw |
| quote: | Originally posted by carlosfm
On that amp, without an input buffer, you have 22k from NI to ground, at the input.
Right?
50k log would not be the ideal.
Big series resistors should not be used.
22k or 25k log would be fine, removing that resistor.
Or try the 50k log pot without the 22k resistor and check DC-offset on the output.
Instead of removing the 22k resistor, you can change it for a much higher value, like 220~330k. |
| quote: | Originally posted by Peter Daniel
As I said, 50k pots (Nobel, Alpha, Panasonic) work perfectly well with 22k shunt resistor, and after using that configuration for 2 years ( on Amp-1) I don't feel like changing anythig ;) |
OK, I have a 10k log one of these, can I use it with a resister? it wont be permanent, just for testing but I still want optimal sound. I am not fussed about how adjustable it.
Either of you two can answer but no need for the b1tching :D :clown: :) |
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| Joe Rasmussen |
| quote: | Originally posted by Peter Daniel
... a [22k] Caddock there will improve the sound of almost any pot. |
Hi Peter
Understand the need for the 22k, but more interested in your comments re sound. This applies when a buffer is used too. I note BrianGT uses/recommends Caddock MK132, I suppose is the one you have in mind.
Joe R. |
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| Peter Daniel |
| quote: | Originally posted by maxw
OK, I have a 10k log one of these, can I use it with a resister? it wont be permanent, just for testing but I still want optimal sound. I am not fussed about how adjustable it.
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Of course you can use it;) |
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| Peter Daniel |
| quote: | Originally posted by Joe Rasmussen
Understand the need for the 22k, but more interested in your comments re sound. This applies when a buffer is used too. I note BrianGT uses/recommends Caddock MK132, I suppose is the one you have in mind.
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I believe this would apply when buffer is used as well, although I'm not using a buffer. I tried many different resistors types and to my ears Caddock in a feedback loop always sounded the best. I'm not crazy about MK132 in other applications, but for some reason it fits sonically here (providing other parts match it).
But the question was about shunt Caddock. Well, I didn't pay that much attention to shunt resistors, but it happen that for recent CES I built two versions of the amp: one had 22k Caddock in shunt position, the other had Vishay VTA55 for shunt. I didn't go to CES, but my associate reported that for some reason the amp with shunt Vishay didn't sound as 3-dimentional as the amp with the Caddock, to the point that they actually didn't play that amp at CES, as the other one was much better sounding. I didn't belive it initially, but later at home we tried comparing the amps, and indeed, Caddock did something to the sound that it became much more spacious and dimentional. From now on I'm using Caddocks for shunt as well, and even when you add a pot the influence is still there ;) |
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| carlosfm |
| quote: | Originally posted by Peter Daniel
Well, giving an opinion on something you didn't try may be misleading. |
Peter, I was giving an oppinion (because I was asked for it) of something I tried.
I have a NI amp. Started as unbuffered and is now buffered (and regulated). |
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| Upupa Epops |
| " Is something wrong in state of amps...", if shunt resistor make the differences in sound. How you can explain it, Peter ? Isn't it only blind faight or placebo effect, 'cos Caddock is more expensive ? :cool: |
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| Peter Daniel |
| quote: | Originally posted by Upupa Epops
" Is something wrong in state of amps...", if shunt resistor make the differences in sound. How you can explain it, Peter ? Isn't it only blind faight or placebo effect, 'cos Caddock is more expensive ? :cool: |
I don't know, why don't you try it? ;) |
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| KT |
Carlos,
Thanks for sharing your experience with this. I certainly think your observations are valid and submitted with good will, and should be welcomed in this thread.
As always, we look forward to hearing more about your audio adventures.
Best,
KT |
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| carlosfm |
| quote: | Originally posted by KT
Carlos,
Thanks for sharing your experience with this. I certainly think your observations are valid and submitted with good will, and should be welcomed in this thread.
As always, we look forward to hearing more about your audio adventures.
Best,
KT |
Gee... thanks.:cool:
Peter, I certainly don't have Avantgarde 103db sensitivity speakers as the guy on the review you posted.
The gain and volume scale was fine for him with those ultra-sensitive speakers.
For me, that's explained.
I have "normal" sensitivity speakers.
Solved!:cool: |
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| Peter Daniel |
Yes, one have to consider that the amp may work with all kind of speakers. Using 50k pot with 22k shunt gives more control over low volume levels and with high efficiency drivers it is actually an advantage.
And as I mentioned, I didn't observe any anomalies when 90dB speakers were used either. One has also consider different taper characteristics of various pots. While it works for me with Nobel, Panasonic and some other, it may no necessary work with all the pots. |
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| Peter Daniel |
| quote: | Originally posted by Upupa Epops
" Is something wrong in state of amps...", if shunt resistor make the differences in sound. How you can explain it, Peter ? Isn't it only blind faight or placebo effect, 'cos Caddock is more expensive ? :cool: |
While my previous response was rather automatic and in order to avoid further complexity in explaning things, I'll try to shed more light on a simple "is it better because it's more expensive" or "is something wrong with the amp" type of inquiries.
Well, Pavel, if you read my previous explanation, you would notice that Vishay VTA55 (at $7/pc.) is actually more expensive than Caddock MK132 ($3.50/pc.), yet Caddock sounds better ;)
Secondly, I wouldn't expect that there was something wrong with the amp, when shunt resistor makes a difference. Contrary, I would rather think, and praised, the revealing properties of the amp (and the system) that make it possible to hear sonic differences in such seemingly unimportant part of the circuit as the input shunt resistor. ;) |
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| Upupa Epops |
| Peter, I don't know which cost all resistors which are made. I mean, that if is some resistor loaded realy deep bellow his nominal wattage and in this case is listened difference between both ones, is something wrong and I'm asking what is it. I was many times present on acoustical comparation tests and I know very well how is easy to deceive human's ear and mainly brain, 'cos man often hear, what can to hear. Realy scientific method for confirmation of your claim must be make quite differently and I hope, that you know how. ;) Man with soldering iron, can hear differences when changes some devices, it is human's nature :cool: . |
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| Vikash |
| These are cheaper in GBP including shipping (works out to about £6.75 for 1) than the same in AUD. I can't find an excuse not to try one (or 10). Take note UK forum members. |
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| Peter Daniel |
| quote: | Originally posted by Upupa Epops
Man with soldering iron, can hear differences when changes some devices, it is human's nature :cool: . |
Well, the guy who first pointed out the difference to me, does not do soldering, and he also didn't know that I put different resistors.
How can you explain that?
He did not hear what he wanted to hear. He heard the DIFFERENCE and he didn't know why.
I'm not much into scientific experiments that's why I'm not making any claims. You should be aware of that. All you see here, are my personal observations. They might be correct or may not, and you use them as you wish.
Coming back on topic, those pots are definitely worth a try, I did like them. |
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| carlosfm |
| quote: | Originally posted by Vikash
These are cheaper in GBP including shipping (works out to about £6.75 for 1) than the same in AUD. |
The price of some good op-amps.:cool:
| quote: | Originally posted by Vikash
I can't find an excuse not to try one (or 10). Take note UK forum members. |
You mean pay 67.50 pounds for 10 resistors?:bawling:
Sorry, but I have more effective ways to spend my money.:angel:
And better sounding.:cool: |
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| Peter Daniel |
| quote: | Originally posted by carlosfm
You mean pay 67.50 pounds for 10 resistors?:bawling:
Sorry, but I have more effective ways to spend my money.:angel:
And better sounding.:cool: |
I thought he was talking about those Alpha pots. Looks like I'm not the only one "hearing" things ;) |
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| carlosfm |
| quote: | Originally posted by Peter Daniel
I thought he was talking about those Alpha pots. |
We were talking about resistors, you and Upupa, and Vikash's post was not very clear, sorry.
Anyway, those resistors you mentioned are expensive too.
| quote: | Originally posted by Peter Daniel
Looks like I'm not the only one "hearing" things ;) |
My new pre is driving me nuts.:cool: |
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| Vikash |
| Good to see you two not at each others throats for once :clown: Yes I meant the pots. That was incredible maths Carlos. 10 of these cost £22 shipped to my door, and you would know how cheap this is if you were over here and tried ordering even a single component from RS or Farnell. ;) |
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| Vikash |
| For those interested, there is a UK jaycar site: www1.jaycarelectronics.co.uk and these pots are priced at £1.55, but minimum order is £20 + £5 postage. Items still come from Australia. |
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| carlosfm |
| quote: | Originally posted by Vikash
Good to see you two not at each others throats for once :clown: Yes I meant the pots. That was incredible maths Carlos. 10 of these cost £22 shipped to my door, and you would know how cheap this is if you were over here and tried ordering even a single component from RS or Farnell. ;) |
You said on your post: "works out to about £6.75 for 1".
Were you saying the price of one pot or is this advanced english and I didn't get it?:D
I multiplied this value by 10. |
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| Vikash |
| You did not factor the static cost of delivery or the bulk discount at 10 pieces. Thus 1 pot is ~$15.50 inc. del., and 10 cost $56 inc. del. (not $155). I thought you ordered from this site? |
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| wrenchone |
| I was rummaging through my stuff, looking for something else entirely, and stumbled across a couple of Allen-Bradley dual cermet 100k linear pots with coencentric shafts. I'll use one of these with 15-20k shunt resistors in an ultrasimple box I'm ginning up to test some preamp boards. Just two knobs in front - the input selector and the coencentric knob for volume/balance. The box can be really small since the power supply will be on the outside. I also have what appears to be a dual 50k Clarostat hot-molded carbon control, also with the same type of shaft, and some of the usual Noble and Alps blue and black conductive plastic types that I can throw in later on for comparison. It'll be interesting to see if I can tell the difference between pots. It's my first new preamp in over 20 years - I can hardly wait... |
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| alcar |
| Thanks for the UK Jaycar link Vikash. ;) I'll order some today. |
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| Vikash |
| Well I've ordered many of them to fill the minimum order quantity, so if you only want a few I can sell you them in a smaller quanitity. Email me if you're interested. |
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| alcar |
| Thanks Vikash . You have email.:D |
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| mrlots2do |
Beware.... really stupid questions.
What is the difference between log and linear pots?
Which type of pot is better?
What is Fake Law? |
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| Vikash |
a quick search can often prevent thread pollution ;)
log/tapered attenuates the singal in a logarithmic(ish) scale, or closer to what humans percieve as volume change.
log is usually the goal, but linear can be 'law-faked' to act as a log pot. Some prefer log to begin with, others swear by law-faked linear. |
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| x. onasis |
| Mr.lotstodo, click |
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| Nuuk |
Crikey - does he know what he's talking about? :rolleyes: |
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| carlosfm |
Hey!
These Alpha pots are really good!:bawling:
I'm testing the 10k log on my preamp and I'm really amazed. :up:
Absolutely no audible channel imbalance since minimum volume.
*** Side note ***
I've heard a "high-end":dead: , expen$ive Goldmund preamp two weeks ago and that thing played only the left channel until almost 1/4 volume.:eek: :bawling:
*** End of side note *** :D
This pot is transparent, "direct", detailed, "airy".
One has to be really talented to pick the good stuff from the cheap things.
Or maby it's a question of feelings.:sing:
It's very easy to buy expensive, isn't it?
Joe, thanks for presenting us to this affordable high-end pots.:angel:
They work like a charm.:cool:
:spin: |
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| mrlots2do |
| quote: | Originally posted by x. onasis
Mr.lotstodo, click |
Thanks x.onasis, Vikash
Nuuk, I actually understood reading that part of your webpage. I'll go back for seconds, thirds and fourths always. Thanks |
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| KT |
OK, this shows that I haven't done my homework (and maybe that it's late and I'm a little bit lazy), but in the GC design, why is it advantageous to have a lower value pot?
I noticed, for example, that Carlos uses the 10k pot. I think Peter tried the 50k value. Why would the 10k value be preferable, if it is?
I bought some 50k pots, myself. Would these be fine to use in Brian and Peter's non-inverted design?
Would it be different in an inverted circuit?
Thanks for indulging me on this.
Best,
KT |
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| Nuuk |
| KT - this may help answer your question! ;) |
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| carlosfm |
| quote: | Originally posted by KT
I noticed, for example, that Carlos uses the 10k pot.KT |
KT, I'm testing the 10k pot on my preamp.
Anyway, on Brian/PD boards you have 22k from input to ground, and there should be no problem in using 10k log there.
You may prefer it over the 50k log if you have "normal" sensitivity speakers (say, up to ~89db).
If you have very sensitive speakers the slight attenuation at the low range of the 22k resistor + 50k pot may be better for you.
Use what you have for now, try it. |
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| KT |
Thanks, Carlos.
If I understand it correctly, the value of the pot along with the 22k shunt resistor affect the response curve of the volume control? The 50k pot will give better control in the lower ranges, then?
I'm not an engineer, but just briefly, how do the pot values affect the input impedence of the amp? Is that something I should keep in mind, or am I just playing around with the volume response curves when I change values, let's say between a 10k and 50k pot?
A little OT, here: has anyone tried the PEC pots in an electric guitar? Must sound very nice.
Thanks,
KT |
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| carlosfm |
| quote: | Originally posted by KT
Thanks, Carlos.
If I understand it correctly, the value of the pot along with the 22k shunt resistor affect the response curve of the volume control? The 50k pot will give better control in the lower ranges, then? |
Yes.
It may be fine, or it may be too much, depending on the sensitivity of your speakers.
| quote: | Originally posted by KT
I'm not an engineer, but just briefly, how do the pot values affect the input impedence of the amp? Is that something I should keep in mind, or am I just playing around with the volume response curves when I change values, let's say between a 10k and 50k pot? |
The pot makes the input impedance of the amp.
10k is fine, 50k is an easy load for the previous stage to drive.
I tend to prefer lower impedance pots (10~25k). |
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| wrenchone |
| The thread that rose from the dead.... I just picked up some 50k single unit Alpha 9mm pots from Mouser. They are amazingly tiny, and very smooth and well damped. I'm currently running a pair of Bourns 50k conductive plastic pots in my new preamp with 19k Dale MF law-fake resistors. They sound OK, though there is some channel imbalance. I'm pulling the preamp this weekend to do some other changes, and I'll throw in the Alphas to see if I notice a difference... |
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| Joseph K |
So as to push this thread another bit forward, I've just noticed in the catalog of RS the little, green, 9mm carbon pots, which are Alps. Apart from the name, they seem to be the exact same thing than those Jaycar/ Alpha taiwan pots.. They are of number 249-9137.
What is your opinion, am I right?!
Ciao, george |
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| mrlots2do |
| quote: | Originally posted by Joseph K
I've just noticed in the catalog of RS the little, green, 9mm carbon pots, which are Alps. Apart from the name, they seem to be the exact same thing than those Jaycar/ Alpha taiwan pots..
They are of number 249-9137. |
I went to RadioShack website but they don't list this pot. Can you post a pic. I'm very much interested.
Phil |
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| Joseph K |
Some more details [compare this with the Jaycar documents]
Elemento resistivo al carbone
Potenza nominale a 70°C 0,05W
Tensione massima 50V~
Tolleranza resistenza ±20%
Errore in serie entro 3dB da -40 a 0dB
Rotazione 300°
Durata rotazionale 15.000 cicli
Temp. di funzionamento da -25°C a +70°C
Dimensioni corpo Largh. 9,5mm; Alt. 11,35mm
Profonditą corpo 7,05mm (singola) 9,55mm (doppia)
Boccola di montaggio Ę 7,35mm; Lungh. 7mm (singolo);
Lungh. 10mm (doppio)
Alberino Ę 6mm; Lungh. 13mm (singola);
Lungh. 15mm (doppia)
Maybe it is present only in the Italian catalog?
Ciao, George |
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| mrlots2do |
| quote: |
Maybe it is present only in the Italian catalog?[/B] |
I can almost understand those specs, LOL. It doesn't say if they are log pots and at what ohm value.
What do they cost in Italy and how much to send me some in the USA?
Phil |
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| Joseph K |
I hope you were able to decipher the Italian ? As a sum, it seems to me that all the main parameters are equal -
power 50 mW, 50 Vac max voltage, 3db tracking error from -40 to 0 db.. etc.
I think there is a common manufacturer, then there are different re-badging distributors..
Still, I might be wrong, this is why I ask.
Ciao, George |
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| Joseph K |
These are the generic parameters, then You have the choice from
10 k lin /log single / dual up to 100k lin / log single /dual.
The price here is 2.48 EUR / single + VAT; 3.18 EUR / double +VAT.
Not cheap - here, in Europe, RS was never cheap.
Should control the situation with foreign transports. If it would not work out, maybe the UK RS branch could be checked? |
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| mrlots2do |
| I just called Radio Shack in USA. They don't have these items listed for USA sales. |
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| motherone |
| The RS listed above is not Radioshack.. It's a supplier in the UK/Europe, I believe. |
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| maxw |
| quote: | Originally posted by motherone
The RS listed above is not Radioshack.. It's a supplier in the UK/Europe, I believe. |
Yes you are right except RS components is pretty much world wide ;) |
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| JandG |
| On the Jaycar silver-carbon pots, should I be getting the Linear or LOG taper..? I would be using them for tube preamp vilome controles @ 100k in dual mono or maybe even stereo pot. |
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| taj |
I would think you will be better off with a log (audio) taper. The volume will rise too quickly (the control will be very sensitive at the beginning) if you use a linear pot. Apparently you can fake a log taper by adding a resistor to a linear pot, so that may be an option for you if the appropriate log pot is hard to find.
You might also want to consider getting or making a stepped attenuator. There's a guy in Taiwan (search on eBay) who makes quite satisfactory ones for a great price. He uses Dale resistors and the switches look and act pretty nice. He will make up the proper resistance for you if he doesn't have the correct one for sale already.
..Todd |
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