The beaty of p2p wiring

[Peter Daniel]

Anybody still arguing that making PCBs is better? I don't see a better way to built this circuit. Of course it's still work in progress but the end is near. Any idea what this might be?

[till]

I can´t understand why i should spend same amount of money for a PCB as for parts needed for a hole amp. (OK, a small amp like the ZEN ones.)

I built bride of ZEN that way, took 2 hours and maybe 20Euro for parts.

[HarryHaller]

Say are those aqua colored caps ceramics?

Hurry please, the peace and well being of the forum may depend on it!

H.H.

[Peter Daniel]

Originally posted by HarryHaller
Say are those aqua colored caps ceramics?


H.H.

I couldn't find a better cap for 10pF value in parallel with 100k ohm in a feedback loop.

[Vince Maida]

I have to agree with H Potter that point to point wiring is a fine way to build something in small quantities. I've worked in the microwave field for 30 years and have prototyped tons of designs
using point to point (albeit very short distances) wiring over a continuous ground plane. The technique works well up to about a couple of gigahertz where the transition from lumped elements to tranmission lines starts to become necessary.
In fact when comparing the performance of designs implemented on a PCB to the point to point technique (especially when the circuit impedances are high), the point to point technique usually results in superior performance. This is mostly due to the higher loss of the PCB dielectric and built in stray capacitance
. At audio frequencies I suppose the additional capacitance inherent in PCB runs can contribute to some signal degradation. Looking at it another way the dielectric constant of air is 1, Glass epoxy=5, even teflon is 2.2. A Lower dielectric constant yields a smaller capacitance for a given trace to ground plane spacing.

[Jocko Homo]

Looks like we are up to 2 microwave types now. And we are both Italian.......hmmmmmmm.

Jocko

[Peter Daniel]

I have just finished prototyping Grey's Aleph X. Everything is mounted on big heat sink. I used 12 output devices per channel and Expect the rails to be +/- 20V.

[Peter Daniel]

That's the close up of front end. I mounted differential mosfets on metal plate and current source mosfet is suspended above. Two green power resistors are the outputs to ground 30 ohm. You can also notice that I used 0.1ohm Caddock resistor at the output. It's 16W and it compact size really fits my setup. I also thin it souns much better than the bunch of parallel resistors. Everything could be so close together that signal traces are practically not existant. I'm really curious about the sound, but still second channel and PS have to be done.

[Peter Daniel]

And the final picture shows how the output mosfets are connected. You really don't need the PCB for that stage, everything fits together and locks in place. By using PCB I would introduce unnecessary connections and longer signal paths. You can see the sensing circuits hanging between the rails. I had pretty hard time puting current sense circuit together but finally I manage to make it compact. That's the place for those circuits, beside output devices and not on the front end board. Grey, you can see that I'm also using Panasonic blue power resistors. With so many of them in the output I would be hard pressed to spend money on anything more expensive. And thank you for the Aleph X circuit.

[Elso Kwak]

Hi HPotter,
It very strongly reminds me to the Jadis amplifiers, known for excellent sound quality.
For even small production I prefer PCB's as making mistakes is very easily done and a major disaster in a poweramp.