Awesome, how did I miss that? Lol. I guess at the time I didn't know what difference I was looking for. Thanks so much AndrewT! I had it backwards after all , I thought A would have a higher gain factor.
It may seem a little bit weird, but I'm actually getting excited looking through the data spec sheets, lol. It's been a good 9-10 years since I looked at this type of "component" data 🙂 .
The BOM calls for:
C1-Polypropylene Capacitor-4.7uf (35V - 50V) (5, 10, 12.5, 15, 22.5, 25mm LS); suggested= P/N: 399-6028-ND
just to clarify; is the 35V-50V AC range, DC range, or [35AC - 50DC] ? the spec sheet for for the suggested shows 30VAC - 50VDC, so Im thinking acceptable DC range?
I was gonna use the WIMA MKS2B044701K00KSSD
Also, I would assume all lead spacing above are acceptable.
Thanks
C1-Polypropylene Capacitor-4.7uf (35V - 50V) (5, 10, 12.5, 15, 22.5, 25mm LS); suggested= P/N: 399-6028-ND
just to clarify; is the 35V-50V AC range, DC range, or [35AC - 50DC] ? the spec sheet for for the suggested shows 30VAC - 50VDC, so Im thinking acceptable DC range?
I was gonna use the WIMA MKS2B044701K00KSSD
Also, I would assume all lead spacing above are acceptable.
Thanks
C1 is the DC block and high pass filter capacitor at the input.
The worst case input voltage is probably a +24dBu from a PA style source. 3Vpk comes from a CDP designed for domestic audio.
18V rating would satisfy both domestic and professional levels, so any of 25V, or higher, is good enough.
The maximum signal that the amp can accept without clipping is much lower.
The worst case input voltage is probably a +24dBu from a PA style source. 3Vpk comes from a CDP designed for domestic audio.
18V rating would satisfy both domestic and professional levels, so any of 25V, or higher, is good enough.
The maximum signal that the amp can accept without clipping is much lower.
Thanks AndrewT.
Just to make sure I understand... +24dBu * (.775) = 18.6, which is how you got the 18V rating mentioned below? Its been a long time, lol.
Are you saying that 3V is the typical peak-peak signal for home audio? (I'm assuming CDP is compact disc player) please forgive my ignorance on the theory.
I'll be OK one of these days, LOL.
Just to make sure I understand... +24dBu * (.775) = 18.6, which is how you got the 18V rating mentioned below? Its been a long time, lol.
Are you saying that 3V is the typical peak-peak signal for home audio? (I'm assuming CDP is compact disc player) please forgive my ignorance on the theory.
I'll be OK one of these days, LOL.
This is what I get at mouser for possible PP caps for C1
Polypropylene (PP) 4.7 uF Film Capacitors | Mouser
Polypropylene (PP) 4.7 uF Film Capacitors | Mouser
evanc:
I picked the Wima mks2 as compared to the suggested Kemet R82CC4470AA30J. I was a little confused that the suggested part was polyester, but figured it wasn't necessarily important due to the suggestion. perhaps I misunderstood, or it was a typo?
I picked the Wima mks2 as compared to the suggested Kemet R82CC4470AA30J. I was a little confused that the suggested part was polyester, but figured it wasn't necessarily important due to the suggestion. perhaps I misunderstood, or it was a typo?
Polypropylene is most often recommended for signal path. Someone more knowledgeable then me will have to explain why.
A coupling capacitor is selected to allow signal to pass. That results in very low signal voltage across it (it passes the signal).
Very low voltage means very low distortion.
If you select your input DC blocking capacitor to have an F-3dB of approx 1 decade below the audio signal, then distortion due to a bad capacitor only becomes significant as that F-3dB frequency is approached.
Do you mind that there is some distortion of a 2Hz (non audio) signal?
On that bassis, of the above, you can use electrolytics (the worst for distortion), or the low distortion polyesters and similar, or the very low distortion polypropylene and similar.
Choose your F-3dB to minimise any audio (audible) distortion.
Very low voltage means very low distortion.
If you select your input DC blocking capacitor to have an F-3dB of approx 1 decade below the audio signal, then distortion due to a bad capacitor only becomes significant as that F-3dB frequency is approached.
Do you mind that there is some distortion of a 2Hz (non audio) signal?
On that bassis, of the above, you can use electrolytics (the worst for distortion), or the low distortion polyesters and similar, or the very low distortion polypropylene and similar.
Choose your F-3dB to minimise any audio (audible) distortion.
+24dBu is 15.849times
0.7746Vac (1mW into 600ohms) times 15.849 = 12.277Vac = 17.362Vpk
Vpp = 2times Vpk (Vpp is useful when reading a scope and you need to convert back down to Vpk and to Vac, if a sinewave).
2Vac (a typical CDP 0dBfs) is 2.828Vpk = 5.657Vpp
0.7746Vac (1mW into 600ohms) times 15.849 = 12.277Vac = 17.362Vpk
Vpp = 2times Vpk (Vpp is useful when reading a scope and you need to convert back down to Vpk and to Vac, if a sinewave).
2Vac (a typical CDP 0dBfs) is 2.828Vpk = 5.657Vpp
as explained in post1832 polyproylene is relatively unimportant for a coupling duty. Select an appropriate F-3dB for effective DC blocking duty and you don't have to worry about added distortion of the audio signal.
BUT ! for filtering duty a completely different set of rules applies.
A capacitor used as a filter of the audio signal will have significant audio signal voltage across it.
Bad capacitors will distort the signal, they can be in series or in shunt. Both will equally distort the audio signal. That's why we rarely (preferably never) see hiK ceramics and electrolytics filtering audio signals.
MKS and similar add a tiny bit of distortion and for ultra clean signal are best avoided.
Polypropylene and other ultra low distortion capacitors can be used to filter audio signals. The quality of the polypropylene film is not considered. The quality of manufacture is a concern. "Audio Quality" capacitors may be of poor construction and unless proved to be good (by measurement, not by listening) should be avoided.
Distortion added by MKS and MKP capacitors is so low that any "test results" one sees are always done when the cap is used as a filter and at relatively high voltage to make the measurement of added distortion rise above the noise floor of the very specialised test equipment.
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I just read post 1832 & 1834 very very clever .. the best explanation I ever saw... thank you Andrew..
Thanks for the explanation AndrewT. I am OK with the math in post 1833. All makes perfect sense. Post 1832 & 1834 goes a little bit deeper than my current level of knowledge. I will have to re-read them after another coffee and try to make better sense of it 🙂 . I honestly do appreciate all of your efforts in helping me understand better!
P.S. is there a source of information that you'd typically recommend for reference on theses types of topics?
P.S. is there a source of information that you'd typically recommend for reference on theses types of topics?
This Forum and the many thousands of links.
But you do need to learn to sort the wheat from the chaff. There is total rubbish posted on this forum as well as the good.
edit:
I can't spell wheat.
why is my spell checker not working for the past 10days?
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Also,
Just an FYI for an perspective Canadian builders.
Cost in Canadian Dollars (CAD) so far:
Primrose:
800VA XFMR = $231.00 (shipped to door)
DIY Audio:
Deluxe 5U = $425.00
Soft Start = $37.00
UNI PSUV3 = $37.00
Badger CB = $59.00
Shipping-NL = $126.00
Customs = Not sure yet
Total: = $915.00 + Customs (Still have to buy all electronic components for the PSU, Soft Start, and Badgers, + input/outputs for case)
Just an FYI for an perspective Canadian builders.
Cost in Canadian Dollars (CAD) so far:
Primrose:
800VA XFMR = $231.00 (shipped to door)
DIY Audio:
Deluxe 5U = $425.00
Soft Start = $37.00
UNI PSUV3 = $37.00
Badger CB = $59.00
Shipping-NL = $126.00
Customs = Not sure yet
Total: = $915.00 + Customs (Still have to buy all electronic components for the PSU, Soft Start, and Badgers, + input/outputs for case)
Thanks AndrewT. Yes, I have been doing a lot of reading here. A lot of "opinion" sometimes bleeds through creating confusion for me 🙂. I am by no means an expert, so sometimes I will be following a thread with a basic understanding, and about 20 pages into it realize that it wasn't necessarily scientific fact based 😛 .