se, srpp, pcb design criteria

[Electroshocked]

Hallo to all tubebuilders!

After being a member of diyAudio, i was motivated to epxeriment with my stocked parts, to find out the best match that could create the best sound according my point of.. ears.

I think that, the following schematic is the one that i liked most. It is a classic single ended design, driven by srpp voltage amplifier. Though i prefer point to point constractions, I decided to design a pcb. So, the following board had to meet the 'point to point constraction' criteria as much as possible.

design criteria:
1. Heaters must be supplied with a twisted pair directly to fillament pins (not on the board).
2. Star grounding begining from the reservoir capacitor and expanding at the cathode bypass capacitors (please see board).
3. The board wiring should be short as possible and the in between distance maximum as possible (avoiding Interference and capacitance).
4. The structure must allow to use multiple packages of some critical components (coupling capacitor, cathode resistors, bypass cathode capacitor..)
5. --> NOW ITS YOUR TURN!

any comments will be appreciated and it will help me to optimize my design before i go on printing it.

Thank you!

Link
http://rapidshare.com/files/235918604/se_srpp_pcb.rar

[azazello]

- AC wires must be away to DC wires.
- RCA connectors, volume control and preamp. tube must be very close.
- High-end is back
proportional to the number of composite parts!!

[Wavebourn]

Clovection flow and radiation have to be taken in mind. I see many PCBs made in China on ePay where electrolytics are directly placed around tubes.
Heavy elements sometimes are placed in the middle of the PCB, so vibrations cause higher deformations of the PCB.

[Wavebourn]

Sorry for the typo; I meant Convection.

[Electroshocked]

Thank you azzazelo and wavebourn for your useful tips!

Here is my first testing board ready to go!

All parts are from my junkbox and i just want to know that its working!

[Electroshocked]

IT IS WORKING!

INAUDIBLE NOISE!

It can be traced only using spectrum analyser.

I use DazyWeb software ( http://www.infinitespectra.com/ ).

The analyzer is set for maximum sensitivity, the 'probe' is attached in the mic input of my sound card and the +20db boost is activated from windows sound mixer properties.

I m VERY surprised by the noise generated from the interfernce of power transformer to the output transformer!
I think that you must do that test before you drill the mounting holes of OPT.

I ve already ordered a toroidal power transformer to run the same test...



I have A LOT to do!!

[athos56]

What did you use to make your board? I keep seeing proto boards, but the process I read about online seemed difficult.

[Electroshocked]

Dear athos56,


Though I ve made several handmade pcbs, this one is made by a proffesional pcb producer. Proto boards are expensive. I intent to order some copies of this in order to build some amps for some friends of mine. So, the total cost will be reduced.

If you want to build an amp just for you, you ll probably have to get your hands dirty (or burned!) using the chemicals needed. It is much cheaper for one or two pcbs.

I agree.. it is difficult and I hate chemicals..

[athos56]

Yeah, I do point to point and still manage to burn/cut/bruise (but not shock) myself in the process... Chemicals... maybe no

[Electroshocked]

Yes, it worked fine..
But there is always something else to do..
The following article seemed to me convincing..

http://www.geofex.com/Article_Folder...nd/stargnd.htm

There were some points that i missed..
Here I go again from the start..
Rewiring..