diyAudio - View Profile: googlyone
Go Back   Home > Forums > Members List

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

googlyone googlyone is offline

diyAudio Member

About Me

  • About googlyone
    Electronics engineer, worked on digital, RF, systems engineering, software. Now in management :(
    Adelaide, South Australia
    Strong interest in electronics, particularly analog, power audio and DSP. Hands on, try it out type
    Operations Manager in product design and manufacturing company
    Real Name


Total Posts
General Information
  • Last Activity: Today 07:43 AM
  • Join Date: 7th November 2006


View googlyone's BlogRecent Entries
Latest Blog Entry

Posted 21st August 2015 at 05:16 AM by googlyone Comments 0
Posted in Uncategorized
Over the years I have played with measuring - well - just about everything in audio.

distortion measurement has been one of these preoccupations, not the least because it is hard to do, and using commercial gear, expensive.

I have built analogue hear to do this, used mixes of analogue and digital and of late played with using modified commercial sound cards. My efforts on the Sound Blaster x-Fi were interesting but ultimately not rewarding enough for me to leave the mods in there.

I have also been playing with using the A/D and D/A converters from my DSP crossover for this purpose. These are modular and use a common I/O plug with power MLCK, SCLK, LRCLK and Data (alone with I2S for the CS4398 and sometimes a digital volume control).

--- notwithstanding the fact that in previous tests I have shown the digital volume control is the MAJOR source of distortion - I will plug ahead with this, and likely leave that out of the test...

Posted 29th March 2015 at 12:51 PM by googlyone Comments 2
Posted in Uncategorized
I have been playing with measuring distortion of signal sources and amplifiers a bit over the last year or two.

I am serious enough to spend some time and thought on this, but not serious enough to sink significant cash into application specific test equipment.

I have a couple of USB Sound Blaster X-fi Music (SB1240) sound cards I use for measurements. The original intent of these was for speaker test and general music. I am pressing these into use for more serious measurement.

The ADC in these is the Cirrus Logic CS5361, which is a pretty good ADC. The DAC is the AKM4396, which is a decent DAC.

When making measurements I hit a problem. The raw performance of the CS5361 is specced to be -99dBc guaranteed an -105dBc typical for THD+N. I couldn't get this.

A few things quickly went onto my list of things to try:
-1- Switching - the sound card has a lot of this - how was it implemented?
-2- Op amps...

Posted 27th January 2015 at 02:07 AM by googlyone Comments 0
Posted in Uncategorized
I recently picked up a pair of, I guess, 1970's Richard Allan three way speakers. The line-up are RA drivers with which I am not familiar. Bass, LP10B, midrange LP5B and tweeters - long dead and replaced with mismatched dome tweeters.

Richard Allan was reasonably popular in Australia in the 70's and 80's, and did some pretty good gear. I was interested to see how these went, but did need to do something about the tweeters.

On pulling the drivers out, I noted a few things:
- The LP10B is a 10 inch bextrene cone woofer, using a 1.5" voicecoil rather than the HP10B's 2" coil. It is also very much an "acoustic suspension" driver - read on.

- The LP5B is very much like a 5" version of the KEF B110 - as used in the LS3A. I read somewhere that Richard Allan made a version of the LS3A under license, but that might be an "internet fact".

- The crossover was made by KRIX, a local speaker manufacturer...

Posted 26th January 2015 at 08:39 AM by googlyone Comments 2
Posted in Uncategorized
The Engineer in me led to plots and graphs, but no pics of the speakers!!!

Attachment 1540

With a neat old badge...

Attachment 1545

The bass driver is a classic Richard Allan unit, you can tell them a mile away by the red (sometimes blue and black) felt:

Attachment 1541

The midrange has a fair bit of the B110 about it's looks, though it is smaller and behaves quite differently. This thing is very much a product of it's era (1970's):

Attachment 1542

The surround on the midrange is stated as PVC in some literature I found. I kind of believe this, though it has been coated with something sticky. It is not sticky on the back.

The cabinets were in moderately good condition. There were some coffee stains on the top of one, and water stains on the side of the other. In the end I sanded and revarnished them.

The timber...

Posted 6th December 2014 at 04:10 AM by googlyone Comments 0
Posted in Uncategorized
Over the last couple of decades I have built an awful lot of power electronics stuff, especially power amplifiers.

So I have bought and used a commensurately large number of power electronic devices.

As a young hobbyist this started with salvaging bits from refuse - especially in the late 70's and early 80's larger power devices were far from cheap. This generally worked really well, as I never did really trust what I pulled out of refuse gear, and I tested stuff that I used. (also not the least as data on power devices came from "equivelant devices" books such as the "Towers guide" and if you were really lucky you found a datasheet somewhere (on paper!). no intenet....

Why the digression?

Oddly with the advent of the internet and subsequently things like EBAY:
- I could get all sorts of things that you just could not buy locally in small quantities.
- Unscrupulous buggers out there started...
Recent Comments
The sound blaster is...
Posted 21st August 2015 at 04:56 AM by googlyone googlyone is offline
How does this unit compare...
Posted 13th August 2015 at 05:54 PM by Harry Manback Harry Manback is offline
Yes it is a philips...
Posted 27th January 2015 at 02:04 AM by googlyone googlyone is offline
The tweeter is not a...
Posted 26th January 2015 at 08:10 PM by Boden Boden is offline
OK that is hardcore!!...
Posted 4th November 2014 at 06:27 AM by wintermute wintermute is offline
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 12:57 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2