Many Chi-Fi amplifiers use the same mini format volume potentiometers that apparently always need to look like quality but often really aren't. Also the difference between linear and logarithmic is not clear in China. Not to complain but these start to scratch after only a few months when one has bad luck and some are durable without issues. No brand name, all look about the same so no visual indication which ones to look for. The ones used are knockoffs of Alps RK097 but in various values. Dual-unit Alps RK097 only exists in 10 kOhm.
So I kindly ask for replacement potentiometers in the same format and of the logarithmic kind and of better quality. Preferably with metal shaft, either knurled/flat/round. Value 10 kOhm, 20 or 25 kOhm. I recall reading here in a thread about unknown (in the West) Japanese brands but I can not find that anymore.
So I kindly ask for replacement potentiometers in the same format and of the logarithmic kind and of better quality. Preferably with metal shaft, either knurled/flat/round. Value 10 kOhm, 20 or 25 kOhm. I recall reading here in a thread about unknown (in the West) Japanese brands but I can not find that anymore.
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I thought it was other way around.
https://www.soundstageultra.com/ind...digital volume control,noise level of the DAC.
https://www.soundstageultra.com/ind...digital volume control,noise level of the DAC.
No attenuation in the digital domain except when it is about FDA for me.
These devices already have volume control by potentiometer. So I look for a source for good quality logarithmic potentiometers in RK097 style.
These devices already have volume control by potentiometer. So I look for a source for good quality logarithmic potentiometers in RK097 style.
I've used heaps of these over the years and never had any issues.
The Alpha that is sold by Jaycar and Altronics in Oz and only comes with a spline shaft but can have AxxK or BxxK.
https://www.jaycar.com.au/10k-ohm-l...os=3&queryId=aa06d676a659686f099069429cafb90f
There was a thread from Peter Daniel on these in 2004.
https://www.diyaudio.com/community/threads/so-i-did-try-all-those-different-potentiometers.40676/
In recent years I've used Bourns PTD90 series and they come in various shaft types and lengths and AxxK or BxxK.
https://www.digikey.com.au/en/products/detail/bourns-inc/PTD902-2020K-A103/3781035
https://www.bourns.com/docs/product-datasheets/PTD90.pdf
The Alpha that is sold by Jaycar and Altronics in Oz and only comes with a spline shaft but can have AxxK or BxxK.
https://www.jaycar.com.au/10k-ohm-l...os=3&queryId=aa06d676a659686f099069429cafb90f
There was a thread from Peter Daniel on these in 2004.
https://www.diyaudio.com/community/threads/so-i-did-try-all-those-different-potentiometers.40676/
In recent years I've used Bourns PTD90 series and they come in various shaft types and lengths and AxxK or BxxK.
https://www.digikey.com.au/en/products/detail/bourns-inc/PTD902-2020K-A103/3781035
https://www.bourns.com/docs/product-datasheets/PTD90.pdf
Yes! Thank you, that Bourns type looks OK. The Alpha in the first link looks exactly like the ones that scratch after a while (but they all look the same and are often also green). If you recommend them I take you used them as replacement for the scratchy Chi-Fi versions?! Will try them when I can find them here.
I recall light grey/white Japanese versions for the Japanese market that were supposedly very good but I don't recall the brand name.
I recall light grey/white Japanese versions for the Japanese market that were supposedly very good but I don't recall the brand name.
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Not pin compatible, too large, too boutique and way too expensive. I look for an exact replacement type for Chinese Class D devices which use a miniature potentiometer. That's because casings are very small. The RK097 style has become kind of standard in these devices.
Off topic: Alps RK27 is criticized a lot but they're better than most would like to admit. You can easily fool someone in blind tests we found out. It was Bruno Putzeys who measured TKD potentiometers and found they distorted more than other brands. Now many like distortion but I won't pay 90 Euro ex shipping for that 🙂
Off topic: Alps RK27 is criticized a lot but they're better than most would like to admit. You can easily fool someone in blind tests we found out. It was Bruno Putzeys who measured TKD potentiometers and found they distorted more than other brands. Now many like distortion but I won't pay 90 Euro ex shipping for that 🙂
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True but not in this case. They scratch because they are cheap garbage and they are often also linear types for some reason. Two good reasons to look for a better logarithmic type.
Being off topic king myself I see in just 10 posts that the first post is quickly forgotten. It reminds me of a kids game taught here. You are with many children in a circle and have to pass the message "Jean-Paul has a broken finger". When it passes the last person the message is quite different and often fatal.
Being off topic king myself I see in just 10 posts that the first post is quickly forgotten. It reminds me of a kids game taught here. You are with many children in a circle and have to pass the message "Jean-Paul has a broken finger". When it passes the last person the message is quite different and often fatal.
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Not fully pin compatible but their size will fit it seems. Probably good quality based on experiences with Sfernice in the past. Thanks, it is on my list.
Thanks but these have a design error as they are mechanically not OK. I have repaired the version with angled contacts several times. The metal part is clamped over the plastic housing and when experiencing some mechanical force the clamp removes itself. A rare case where the original is less good than its copies. Die taugen nix. A large(r) volume control knob is out of the question with these. My guess is that the quite good RK097 (but 10 kOhm only) is an improved version of RK09. Same construction as other Alps types with screws/rivets going through the housing.
So I have: Bourns PTD902, Vishay Sfernice P11A and the Alpha Taiwan potentiometers. Any other ideas?
So I have: Bourns PTD902, Vishay Sfernice P11A and the Alpha Taiwan potentiometers. Any other ideas?
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You are right. Over the years this has not been an issue for me, using these in a variety of musical amps on stage. Impacts onto the shaft are kept to the mounting threaden, thus much more robust than german vintage Preh, Ruwido etc. On the other hand these are still available with numerous values at a budget price. A niche product - as our hobby.
They are used in this otherwise quite good Destiny/Ipar tube hybrid preamp but rarely survive shipping even when the knobs are taken off for transport:
https://destiny-audio.com/products/destiny-pre-amplifier
They are mounted as usual but as there is no protection or retention clip on the shaft so:
Impacts on the front side of the shafts cause the shafts of both potentiometers to open the clamps and then push the plastic housings + PCB to the back so the potentiometers fall apart. Not robust at all but the device has high weight which does not exactly help. Very difficult to solve as these are the rare angled PCB mount version in unusual value. The clamp is like a spring and refuses to function as a clamp anymore. My solution is to make a new metal clamp over the complete potentiometer but this is a time consuming operation. Finger weg
https://destiny-audio.com/products/destiny-pre-amplifier
They are mounted as usual but as there is no protection or retention clip on the shaft so:
Impacts on the front side of the shafts cause the shafts of both potentiometers to open the clamps and then push the plastic housings + PCB to the back so the potentiometers fall apart. Not robust at all but the device has high weight which does not exactly help. Very difficult to solve as these are the rare angled PCB mount version in unusual value. The clamp is like a spring and refuses to function as a clamp anymore. My solution is to make a new metal clamp over the complete potentiometer but this is a time consuming operation. Finger weg
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Could? simply use a Full sized Pot or Attenuator. .😉
Not as if the cheap Chi Fi junk warrants it though.
Not as if the cheap Chi Fi junk warrants it though.
I tried one of the Vishay/Sfernice P11A pots in front of my cap coupled B1 buffer. A few things, the only ones available at Mouser are linear taper. I found a log taper Alps Blue Velvet to suit me better. With the Vishay, there was a small range between full attenuation, only one channel playing and then too much signal. Also the shaft size is the smaller 3mm(1/8") size with a slotted end, so you may not be able to retain your original knob.
Ha OK good info. P11A should be available with 6 mm shaft somewhere. Linear taper versions are unusable for correct volume control.
Some sound better than full size branded amplifiers even without any reworking. Frustrating to guys going back in time 🙂
Full size potentiometers don't fit as explained plain and clear. The Chi-Fi amplifiers with MA12070 use original Infineon (Germany/Austria) chips. We would probably not have found the chip without trying out Chi-Fi amplifiers.
Some sound better than full size branded amplifiers even without any reworking. Frustrating to guys going back in time 🙂
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