The added cost is not that big in relation to the finished product.
The cost is maybe double a 2" X 3" in ceramic is $22.50 in quantity 100.
Is it audible maybe, but it sure makes nice man jewelry and is a pleasure to work with. the cost of PCB's is small compared to metal and finishing.
The cost is maybe double a 2" X 3" in ceramic is $22.50 in quantity 100.
Is it audible maybe, but it sure makes nice man jewelry and is a pleasure to work with. the cost of PCB's is small compared to metal and finishing.
Sorry to hear this from you Stuart
Why? Bright red boards are cool. I have one of Pete Millet's power amps using one.
Good info, thanks.
Dan.
http://www.analog.com/library/AnalogDialogue/archives/43-09/EDch%2012%20pc%20issues.pdf
Last edited:
Discreet ceramic caps suffer from mechanical resonances. Oh, Lord, some are not so bad in SMDs.
Somewhat relevant to the current discussion, this appears to be a very interesting book ... Contamination Effects on Electronic Products - Tautscher - Google Books
Because you are working with high impedance tube circuits and surely you are aware about various publications on leakage, DA, etc in different insulators (Keithley, etc) and conventional approach for grid circuits (teflon/ceramic solder terminals, etc).
You can read discussions in Solid-state, when the capacitive load of so-called VAS is several pF and then you stated that
Personally, I would advise you to review your judgement
I'm not building electrometers. And I'm not building microwave gear. This is audio. Impedances are in the 10s of k and lower.
Tubes are made of glass and steel, transistors are made from epoxy. So how does the nonideality of a pF of circuit board (and that's generous!) affect that? And what is the magnitude of that modulation? Scale, Dmitri, scale!
Tubes are made of glass and steel, transistors are made from epoxy. So how does the nonideality of a pF of circuit board (and that's generous!) affect that? And what is the magnitude of that modulation? Scale, Dmitri, scale!
I built one that way perhaps 20 years ago. Learned my lesson about trading off real mechanical and reliability advantages against nearly-nonexistent electrical advantages. Never used PTFE for circuit boards after repairing several Berning amps where the flexure caused traces to break and lift.
I think the frequency reference is misleading. In the case of audio its a dynamic range issue. If you start with 10K Ohms and an impedance nonlinearity of 100 dB it translates into nonlinearities of gigaOhms. Its certainly possible to see a change in the .00001% range showing up for may reasons. Because of the scale 10K may not be low enough to reduce/eliminate the effect. Not much of an effect but it could be a bigger issue with high impedances. In this case it may be a voltage coefficient that's high enough to cause problems.There are a lot of these small issues that can turn up and bite you. For example a 600 Ohm source into a 10K load will have an amplitude error enough to throw off a precision measurement. Add cable capacitance and its hard to get trustworthy measurements at 100 KHz. 50 Ohms reduces the errors a lot.
Whether these errors are audible either individually or in concert with others is a real question, but I would rather deal with them if its easy than ignore them.
Glass epoxy does not make for a good capacitor but the materials that do have issues making them not suitable for PCB's. I got Tektronix to make PCB's for me back at Spectral, using the special material they cooked up to deal with hook. It worked and I believed it sounded much better. They were clear and really cool. However it had no fiberglass reinforcement so really fragile and some common solvents from the period would dissolve the board instantly. Then Tek closed down the PCB shop and we couldn't get the boards any more.
PCB trace capacitance non-linearity effect in link stages with kohm resistors is a nonsense. One has to be aware of possible stray capacitance effect between traces and possible trace crosstalk, not to meditate on trace capacitance nonlinearity. Be rather afraid of strong capacitance nonlinearities in JFETs.
I resolved that issue in the easiest possible terms available to me. I had two identical boards made, one using glass fibre boards with 35 microns of copper (the absolute standard), and another from the same manufacturer but using 70 microns of copper. I filled them up and adjusted them to exactly the same at 1 kHz. Then I listened. Simple power amps based on LM 391-100 chip driver circuitry with discrete output stages based on Motorolola MJ 21193/21194 power devices.
No surprises there, the thicker one did sound better. Not incredibly better, no revelation, but audibly better. I noted that the difference was across the board, meaning from the lowest to the highest frequencies, the midrange showing the least change.
The other materials people mentioned are not available to me.
No surprises there, the thicker one did sound better. Not incredibly better, no revelation, but audibly better. I noted that the difference was across the board, meaning from the lowest to the highest frequencies, the midrange showing the least change.
The other materials people mentioned are not available to me.
What, exactly, is the problem with glass-epoxy ?
Too much conductivity ? Mechanical resonances ?
While my 5GHz computer use such material for his mother board, any evidence by measurements that epoxy makes a difference in the 10MHz range in audio, compared with other exotic hype material ?
Can-we refer to any blind test showing obvious listening differences ?
Too much conductivity ? Mechanical resonances ?
While my 5GHz computer use such material for his mother board, any evidence by measurements that epoxy makes a difference in the 10MHz range in audio, compared with other exotic hype material ?
Can-we refer to any blind test showing obvious listening differences ?
Couple of decades ago, I assembled a phono stage on solid glass plates.
(through hole, with ceramic stand-offs and leads soldered to copper washers on the opposite side)
Looked grand, didn't sound that well (also a solid neurocognitive enhancement stimuli abuser in those days)
Is that circuit hook capacitance dive restricted to dissimilar materials ?
- Status
- Not open for further replies.