I am considering the following teflon caps for the 50/500 portion of the RIAA network. Does anyone have any experience with these or lower values?
https://solen.ca/en/products/solen-...ors-s3q330n-0_33uf-1000v-teflon-film-tin-foil
https://solen.ca/en/products/solen-...ors-s3q330n-0_33uf-1000v-teflon-film-tin-foil
That's huge, larger caps can pick up more hum/noise from the surroundings. Its also a pretty large value for an RIAA network, usually the values come out somewhere in the 3 to 30nF range for the main poles and zeroes - I've done it with 3n3 and 12n for instance, 330nF seems a suboptimal choice to me, that feels more like a value for a rumble filter where the poles are around 15Hz... Beware of self-inductance too as the RIAA network needs to work nicely upto 20kHz, even for the 50Hz components.
I am currently using a 22nF Russian teflon and want to experiment with larger values to get the impedances down. The 2122 Hz pole uses a 680pF Russian teflon, replacing a polystyrene type. The teflon sounded significantly more detailed and cleaner IMO. I haven't necessarily decided on the 0.33uF, rather perhaps the 0.1 or the 0.22uF value (cost doesn't reduce significantly though). Any thoughts by anyone on using COG/NPO capacitors?
The hum/noise issue hasn't been completely worked out yet. The moving coil head amp is an enclosed battery powered unit with slightly more noise, with the phono network adding a slight amount of hum. This is currently an open air breadboarded thingy with poor power supplies as of yet. This is being tested feeding a Topping PA-5 class D amplifier fairly well reviewed by ASR.
https://www.audiosciencereview.com/forum/index.php?threads/topping-pa5-review-amplifier.28512/
The hum/noise issue hasn't been completely worked out yet. The moving coil head amp is an enclosed battery powered unit with slightly more noise, with the phono network adding a slight amount of hum. This is currently an open air breadboarded thingy with poor power supplies as of yet. This is being tested feeding a Topping PA-5 class D amplifier fairly well reviewed by ASR.
https://www.audiosciencereview.com/forum/index.php?threads/topping-pa5-review-amplifier.28512/
This is what John Curl of Blowtorch/Vendetta fame told me in another RIAA cap thread:
"Hi Wintermute, follow Zung's advice and get the component tester. I still recommend the REL RT polystyrene caps for my RIAA stages. Everything I have designed from Vendetta, Constellation, Parasound, and others always use REL RT caps in the RIAA. 1% matching is a problem to purchase, but you can buy a few extra, and hope for a good 2 channel match. Also you can balance the cap values by adding a small polystyrene cap in parallel to one of the caps to get closer in tolerance."
Complete thread https://www.diyaudio.com/community/threads/capacitor-recommendations.385006/
"Hi Wintermute, follow Zung's advice and get the component tester. I still recommend the REL RT polystyrene caps for my RIAA stages. Everything I have designed from Vendetta, Constellation, Parasound, and others always use REL RT caps in the RIAA. 1% matching is a problem to purchase, but you can buy a few extra, and hope for a good 2 channel match. Also you can balance the cap values by adding a small polystyrene cap in parallel to one of the caps to get closer in tolerance."
Complete thread https://www.diyaudio.com/community/threads/capacitor-recommendations.385006/
put them on a good analyzer and see that they stop acting like good caps at a much lower frquency than same value polystyrene....
... which is what i'd recommend that you use instead. spend that money on some hard to get JFETs or something!
the rel cap that wntrmute2 mentions is a good one to use and it's much cheaper.
... which is what i'd recommend that you use instead. spend that money on some hard to get JFETs or something!
the rel cap that wntrmute2 mentions is a good one to use and it's much cheaper.
I have used all manner of caps, though no Rel-Cap RTE's or COG/NPO's. The caps used in the past (over the past 30 years or so) included Wima FKP's and MKP's, Rifa polystyrene's and a host of others I can't remember. The Russian teflon's were the most analytic, though being to a large degree sterile sounding. My suspicion is that they reveal circuit issues as opposed to mitigating them, hence can require voicing the network as a whole. IMO there is nothing wrong with this as that is my plan in the end (by whatever means) anyway.
Before going to that resort I want to experiment in mitigating the sterility of the sound while keeping the analytic. IMO the whole of the network is beginning to analytically bloom more so now in the midrange, seemingly in part by lowering the higher frequency aggression. Thats the direction I prefer the sound to go, while also maintaining and/or opening up the lower registers to control the weight of the whole.
Currently there are no coupling caps from my Denon 103R moving coil cartridge to the output. The Topping amplifier has a gain control and AC coupling and shuts down once in a while (perhaps 20 times or so now) on low frequency transients.
Before going to that resort I want to experiment in mitigating the sterility of the sound while keeping the analytic. IMO the whole of the network is beginning to analytically bloom more so now in the midrange, seemingly in part by lowering the higher frequency aggression. Thats the direction I prefer the sound to go, while also maintaining and/or opening up the lower registers to control the weight of the whole.
Currently there are no coupling caps from my Denon 103R moving coil cartridge to the output. The Topping amplifier has a gain control and AC coupling and shuts down once in a while (perhaps 20 times or so now) on low frequency transients.
Teflon is very stable.
I'd expect at least 100 years for any characteristic to change.
Not sure "they" have any sound of their own, sound comes from the whole circuit design.
IF a capacitor changes sound, audibly, it is broken
As in : open - shorted - >100% away from expected value - lossy where resistive component (series or parallel) is comparable to impedance at working frequency.
I expect none of that in a high quality Teflon cap, even less in an expensive one..
You can also use a value that's a bit too small in a capacitor's position and then trim it up to spec by paralleling smaller ones, since the caps come in lots of pF sizes suitable for use in trimming.