I received some Alpha pots from Australia.
Three 50k dual log pots and two 10k dual logs.
They are really small, cute.
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.
Gotta try them one of these days.
Three 50k dual log pots and two 10k dual logs.
They are really small, cute.
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.
Gotta try them one of these days.
carlosfm said:I received some Alpha pots from Australia.
Three 50k dual log pots and two 10k dual logs.
They are really small, cute.
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.
Gotta try them one of these days.
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.
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.
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.
TaaJ said:
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.
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.
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.
carlosfm said:
Peter Daniel said: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
Joe Rasmussen said:
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
Re: To use Caddock or not to use Caddock, that's the question !
I don't know, why don't you try it?
Upupa Epops said:" 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 ?
I don't know, why don't you try it?
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.
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.
Re: To use Caddock or not to use Caddock, that's the question !
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.
Upupa Epops said:" 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 ?
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.
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 .
Man with soldering iron, can hear differences when changes some devices, it is human's nature .- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.