Styroflex Capacitors - capacitance value options - U87 clone

[sarakisof]

For  R18,R19 2.2k resistors:
It was written somewhere here into basic thread (dont remember exactly who),  that it could be a good idea to use  0.1%  tolerance resistors for easiest matching. If so, could these be an ideal option?
http://gr.mouser.com/Search/ProductDetail.aspx?R=PTF652K2000BZBFvirtualkey61300000virtualkey71-PTF652K2000BZBF

its 500v instead of 250v of the one with 1% tolerance but i think it will be okey. and i suppose if it could be about purchasing 10x1%, now i have to buy less?...

ps. a lil bit offfff topic but...  :

 

[Khron]

Unless you're working with tube stuff or other high-voltage devices, voltage ratings in resistors are pretty much irrelevant (imho)
Especially when they're in the signal path...

Plus i'm, let's say, skeptical about "audio quality" resistors. 2.62eu for ONE? Gimme a break!.. ;D You could buy a few tens (if not hundreds) from a less "boutique" brand, and hand-match them yourself to at least 0.1% (with a half-decent multimeter and a few minutes), but that's just me I've never been a fan off throwing money at a problem...

And if you're worried about noise... For example the Rode NT2-A is rated at a mere 7dB self-noise, and it uses all SMD resistors. And you can bet your booty they haven't used 2$ a piece resistors I'd be surprised if they bothered with anything more than "normal" 1% ones.

 

[ln76d]

Unless you're working with tube stuff or other high-voltage devices, voltage ratings in resistors are pretty much irrelevant (imho)
Especially when they're in the signal path...

Plus i'm, let's say, skeptical about "audio quality" resistors. 2.62eu for ONE? Gimme a break!.. ;D You could buy a few tens (if not hundreds) from a less "boutique" brand, and hand-match them yourself to at least 0.1% (with a half-decent multimeter and a few minutes), but that's just me I've never been a fan off throwing money at a problem...

And if you're worried about noise... For example the Rode NT2-A is rated at a mere 7dB self-noise, and it uses all SMD resistors. And you can bet your booty they haven't used 2$ a piece resistors I'd be surprised if they bothered with anything more than "normal" 1% ones.

In fact, they used 2$ resistors - price for all in the circuit

 

[Khron]

THAT expensive? Well, then again, there ARE also those 2-3 1G ones, which might not be the 0.0x cents the more usual ones are...

But hey - it's how you use it... or something-something ;D

 

[RuudNL]

It is the same with 'boutique' capacitors. ($25/pc.)
Maybe I am only using the 'good' ones, but I never heard a significant difference between capacitors.
IMHO what people think to 'hear', is the hole in their wallet!

 

[Khron]

Confirmation bias is a fickle b*tch Just earlier this week, i came across this little gem:

http://www.soundonsound.com/reviews/preamp-post-mortem

Need i say more? ;D

 

[RuudNL]

;D

 

[ln76d]

Maybe I am only using the 'good' ones, but I never heard a significant difference between capacitors.
IMHO what people think to 'hear', is the hole in their wallet!

Ok, i need to admit, that i hear difference between capacitors (of course not always, not every part of the circuit etc.).
Also did many blind tests. In fact i learned how to hear the equipment, not just signals, working few years in audiphile equipment shops some years ago. That was the only good thing from whole this work, rest was like spending time in psychiatric hospital.
Anyway, quality (or intended effect) doesn't rise with the price.
There's many great electronic parts which you can buy really cheap.
Tests, tests, tests - if you have a little more time, then really try.
Best option to start is microphone output cap, before transformer (tube or fet).
I did many tests, my favourite result is the lowest capacitance possible (to get full response) and metal paper dielectric.
Really worth to spend some time on this.

 

[Khron]

Metallized paper? You don't want that. I've seen more than a few of those transparent-cased paper-and-foil Rifa X2 / Y2 caps blown, both myself and online, due to decomposing / old age

https://www.google.fi/search?client=firefox-b-ab&biw=1651&bih=850&tbm=isch&sa=1&q=rifa+failed&oq=rifa+failed&gs_l=psy-ab.3...11184.11558.0.11732.4.4.0.0.0.0.181.296.0j2.2.0....0...1.1.64.psy-ab..3.0.0.CqRdLIcxIvs

 

[ln76d]

X2/Y2 are completely different type an application - mostly, psu, high current - yeap they can blow.
I had in mind hermetically sealed MP, MBM, PIO etc.

 

[sarakisof]

Plus i'm, let's say, skeptical about "audio quality" resistors. 2.62eu for ONE? Gimme a break!.. ;D You could buy a few tens (if not hundreds) from a less "boutique" brand, and hand-match them yourself to at least 0.1% (with a half-decent multimeter and a few minutes), but that's just me I've never been a fan off throwing money at a problem...

Tottaly agree.

In fact, they used 2$ resistors - price for all in the circuit

hahahah

 

[sarakisof]

Another question: tested today my interface's (Focusrite Saffire Pro 24 DSP - officialy advertised at 48V.) voltage phantom power  with a simple DMM and its 43,5V in both mono xlr inputs.
Could this be a problem for my future built of the U87 clone operation or smthing?
(international spec voltage is 48V +- 4V.  so  i may be out of limits?)

 

[ln76d]

After build measure it inside microphone. Your bias voltage value also will be lower. Borrow different preamp or phantom supply and verify again. Many preamps (especially built in audio interfaces) have weak phantom supply.

 

[winner]

I don't understand, why did you choose the 630 v? It is highest circuit voltage of 48 v, not can choose small voltage? Is it in order to sound? Who can tell me the answer :-*

 

[RuudNL]

The voltage of the phantom power is 48 Volts. But...that is without a load!
With every mA load, the voltage drops 3.4 V (6.8 / 2).
So, a microphone drawing 4 mA has a maximum working voltage of 34.4 V.
Anyway, in a solid state microphone the voltage for the audio part can never be higher than 48 V.
(In the case of a DC/DC converter, the polarisation voltage can be higher however.)
So if you use 50 or 63 V capacitors for the audio part, you're fine.
The only reason to use capacitors with a higher voltage rating, is that they usually have a lower leak current, but that is only important in parts of the circuit with a high impedance.

 

[winner]

The voltage of the phantom power is 48 Volts. But...that is without a load!
With every mA load, the voltage drops 3.4 V (6.8 / 2).
So, a microphone drawing 4 mA has a maximum working voltage of 34.4 V.
Anyway, in a solid state microphone the voltage for the audio part can never be higher than 48 V.
(In the case of a DC/DC converter, the polarisation voltage can be higher however.)
So if you use 50 or 63 V capacitors for the audio part, you're fine.
The only reason to use capacitors with a higher voltage rating, is that they usually have a lower leak current, but that is only important in parts of the circuit with a high impedance.

Thank you, teacher, why do I often see someone who USES a lot of pressure-resistant capacitors so that they can really sound good? It's just a psychological effect

 

[Khron]

"Because reasons" Or rather, because of various myths and pieces of misinformation...

https://www.youtube.com/watch?v=BYTlN6wjcvQ

Thank you, teacher, why do I often see someone who USES a lot of pressure-resistant capacitors so that they can really sound good? It's just a psychological effect

 

[winner]

"Because reasons" Or rather, because of various myths and pieces of misinformation...

https://www.youtube.com/watch?v=BYTlN6wjcvQ

Thank you. Maybe it's psychological

 

[RuudNL]

"Because reasons" Or rather, because of various myths and pieces of misinformation...

https://www.youtube.com/watch?v=BYTlN6wjcvQ

I really like this man! Especially where he talks about the 'delay' the guitar player could hear in his cable!  ;D
Also about the number of bits and 'dithering'. "Of course it is technically better, but can you hear it?!"

 

[Khron]

Since it's so appreciated, here's the "sequel" to that, from the same author - https://www.youtube.com/watch?v=Zvireu2SGZM ;D