diyAudio - Entries for May 2013
Go Back   Home > Forums > Blogs > My DIY projects

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
I returned to DIY electronics in 2009 after a 20 year pause by building a few kits to get in shape. This blog is for me to keep track of my progress.
Old

Measurements with a sound card

Posted 13th May 2013 at 10:08 PM by alexcp (My DIY projects)
Updated 7th September 2013 at 10:36 AM by alexcp (Updated for ASIO4ALL)

I am using a USB sound card for measurements. It's a pain, but I have nothing better yet.

The sound card is the E-MU 0204. I've chosen it for the specs:
  • Dynamic Range (A-weighted, 1kHz, min gain): 113dB
  • Signal-to-Noise Ratio (A-weighted, min gain): 113dB
  • THD+N (1kHz at - 1dBFS, min gain): -101.9dB (.0008%)

The sound card is intefaced to the real world by Pete Millett's sound card interface.

The software is SpectraPLUS 5.0 by Pioneer Hill Software (PHS). (No link because my antivirus says their web site is infected.) The software runs on an old MacBook running Windows 7 in Boot Camp.

The results do not seem to be affected by nearby computers, flurescent lights, switching power supplies, etc.

The results are affected by:
  • Windows Mixer settings (levels and sampling rates)
  • Software settings (levels and sample rate)
  • Grounding of the sound card, the interface, and the device under test

The greatest source of pain is...
Attached Thumbnails
Click image for larger version

Name:	E-MU 0204 loopback spectrum.png
Views:	296
Size:	37.4 KB
ID:	1055   Click image for larger version

Name:	E-MU 0204 loopback THD+N vs Freq.png
Views:	160
Size:	37.5 KB
ID:	1056   Click image for larger version

Name:	E-MU 0204 ATEST spectrum.png
Views:	143
Size:	37.1 KB
ID:	1057   Click image for larger version

Name:	E-MU 0204 ATEST THD+N vs Freq.png
Views:	169
Size:	37.5 KB
ID:	1058   Click image for larger version

Name:	NE5532 power amp spectrum.png
Views:	199
Size:	32.4 KB
ID:	1059  

Click image for larger version

Name:	NE5532 power amp THD+N vs Freq.png
Views:	327
Size:	31.9 KB
ID:	1060  
alexcp's Avatar
diyAudio Member
Posted in Instrumentation
Views 691 Comments 0 alexcp is offline
Old

NE5532 power amplifier

Posted 12th May 2013 at 08:51 PM by alexcp (My DIY projects)

This is a project developed by Douglas Self and published in the Elektor in October and November 2010.

The idea is rather unusual: "An interesting power amplifier can be made by connecting enough 5532s in parallel, how about 32 for a start? This may sound like a radical course of action, but it actually works very well, making it possible to build a very simple amplifier that retains not only the excellent linearity but also the power-supply rejection and the inbuilt overload protection of the 5532, which reduces the external circuitry required to a minimum."

Elektor used to sell PCBs for this project, which I used. I modified the circuit slightly to incorporate an active volume control along the lines of Douglas Self's preamplifiers.

Here is the result:
Attached Thumbnails
Click image for larger version

Name:	NE553201.jpg
Views:	566
Size:	194.4 KB
ID:	1045   Click image for larger version

Name:	NE553202.jpg
Views:	383
Size:	147.9 KB
ID:	1046   Click image for larger version

Name:	NE553203.jpg
Views:	526
Size:	170.5 KB
ID:	1047   Click image for larger version

Name:	NE553204.jpg
Views:	543
Size:	205.0 KB
ID:	1048   Click image for larger version

Name:	NE553205.jpg
Views:	1147
Size:	246.3 KB
ID:	1049  

Click image for larger version

Name:	NE553206.jpg
Views:	1876
Size:	262.7 KB
ID:	1050   Click image for larger version

Name:	NE553207.jpg
Views:	434
Size:	203.0 KB
ID:	1051   Click image for larger version

Name:	NE553208.jpg
Views:	937
Size:	227.1 KB
ID:	1052   Click image for larger version

Name:	NE553209.jpg
Views:	255
Size:	236.5 KB
ID:	1053   Click image for larger version

Name:	NE553210.jpg
Views:	1893
Size:	253.3 KB
ID:	1054  

alexcp's Avatar
diyAudio Member
Views 2503 Comments 2 alexcp is offline
Old

Eternally Penultimate Zen - mod #4

Posted 11th May 2013 at 09:32 PM by alexcp (My DIY projects)
Updated 12th May 2013 at 05:24 PM by alexcp (Added pictures, links)

My first solid state amplifier build, in 2009, was The Penultimate Zen, aka Zen Variations Part 4, aka ZV4. It was built with the parts I could find back then, without knowing where to look. It ended up big, heavy with two 400VA toroidal transformers, ugly inside with some electrical tape here and there, without proper grounding, etc., etc. I was as disappointed with the sound as my wife was disappointed with that heavy black metal brick gathering dust.

My first mod on ZV4 came after I turned my disappointment into finding better part suppliers. I returned to my ZV4 and replaced the output caps with something marginally more decent from eBay. The sound improved a notch. Aha!

My second mod was to rebuild the power supply. I threw away one of the toroids, added a softstart circuit from Hypex, and put in a CRC filter with some Mundorf HC caps. One power supply for two single ended channels forced me to learn about grounding and add input transformers and balanced...
Attached Thumbnails
Click image for larger version

Name:	diyaudio46.jpg
Views:	347
Size:	216.0 KB
ID:	990   Click image for larger version

Name:	diyaudio47.jpg
Views:	227
Size:	224.3 KB
ID:	991   Click image for larger version

Name:	diyaudio48.jpg
Views:	220
Size:	171.6 KB
ID:	992   Click image for larger version

Name:	diyaudio49.jpg
Views:	606
Size:	239.5 KB
ID:	993   Click image for larger version

Name:	diyaudio50.jpg
Views:	357
Size:	211.0 KB
ID:	994  

Click image for larger version

Name:	diyaudio51.jpg
Views:	406
Size:	198.6 KB
ID:	995   Click image for larger version

Name:	diyaudio52.jpg
Views:	409
Size:	203.8 KB
ID:	996   Click image for larger version

Name:	diyaudio53.jpg
Views:	346
Size:	152.3 KB
ID:	997   Click image for larger version

Name:	diyaudio54.jpg
Views:	728
Size:	241.4 KB
ID:	998   Click image for larger version

Name:	diyaudio56.jpg
Views:	198
Size:	150.2 KB
ID:	999  

alexcp's Avatar
diyAudio Member
Views 1007 Comments 0 alexcp is offline
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 08:23 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2