Search found 263 matches

by ricardo
Tue Jan 12, 2016 6:09 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 499
Views: 773195

Re: A Low Noise Balanced In Moving Coil Preamp Using the ZTX

I tested a lot of ZTX medium power transistors circa 1980 when I was playing with MC cartridges & preamps, and so did Peter Baxandall. They did have small Rbb' but you had to select for 1/f noise. Once I found the Hitachi 2sa108x & 2sc254x devices, I stopped looking as they were better and d...
by ricardo
Mon Jan 04, 2016 9:42 pm
Forum: Stored Code
Topic: RIAA VST Plug-Ins
Replies: 2
Views: 11873

Re: RIAA VST Plug-Ins

mediatechnology wrote:I've tried the 96 kHz VST plug-in in Audacity and it sounds really good.
Audacity locates the plug-ins in "Effects|Container|SynthEdit"

Here are the links to the dlls:
I didn't know you can use VST plug-ins in Audacity :o :shock:
by ricardo
Wed Dec 16, 2015 5:35 pm
Forum: Stored Code
Topic: Hello - Anyone In Here?
Replies: 33
Views: 46684

Re: Hello - Anyone In Here?

(Just like I hate the half-second (?) latency delays when in a fast-paced conversation on a cell phone.."OK..OK...Eric...you talk and I'll be quiet".) Ma Bell landlines didn't mess with me like that! <g> Maybe you're too young to remember transatlantic phone calls :lol: Repeaters (amps pl...
by ricardo
Mon Dec 14, 2015 6:50 pm
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 455246

Re: Flat Phono Preamp Based on John's P10 and 2SK389

mediatechnology wrote:I didn't post the OPA2134 versus NJM2068 results because they are essentially identical.
Do you mean OPA2134 & NJM2068 have similar noise performance with Stanton 681?
by ricardo
Sat Dec 12, 2015 4:39 pm
Forum: Stored Code
Topic: Hello - Anyone In Here?
Replies: 33
Views: 46684

Re: Hello - Anyone In Here?

There was an expectation that we would end up using digital output mics, and that still could happen, but old shool analog mics are not going away anytime soon so analog mic preamps will stay with us for a while. With my mike designer's hat on .. I like to have my mikes behave up to 135dB spl and d...
by ricardo
Thu Nov 26, 2015 5:44 pm
Forum: Stored Code
Topic: Hello - Anyone In Here?
Replies: 33
Views: 46684

Windows Mixer replacement?

I did a fair amount of DSP in the early 90's with standalone boards & PC cards. Mostly machine code (and processing on DOS PCs in C) After 2 decades in the bush, I find everything has changed and computing power that I only dreamt about is available from the cheapest PC you can buy. But the know...
by ricardo
Fri Nov 20, 2015 4:03 pm
Forum: Pro Audio Design
Topic: A Flat Moving Coil Preamp Using Paralleled Amplifiers
Replies: 42
Views: 103630

Re: A Flat Moving Coil Preamp Using Paralleled Amplifiers

Richard published his design in 1981: http://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&t=749&start=14 Leach came 18 years later. The original Leach article was in Audio, 1979 or 1980. A friend of mine built it and was disappointed so I said I would do him a better one. All I d...
by ricardo
Tue Nov 17, 2015 11:05 pm
Forum: Pro Audio Design
Topic: A Flat Moving Coil Preamp Using Paralleled Amplifiers
Replies: 42
Views: 103630

Re: A Flat Moving Coil Preamp Using Paralleled Amplifiers

The "Altoids" circuit is from Marshall Leach, RIP: http://users.ece.gatech.edu/mleach/headamp/ Yes. But there's a HUGE difference in noise & THD between Leach and my versions. "The history of this design is that a friend built http://users.ece.gatech.edu/mleach/headamp/ and was d...
by ricardo
Wed Nov 11, 2015 12:48 am
Forum: Pro Audio Design
Topic: modified GFCI
Replies: 92
Views: 163033

Re: modified GFCI

Thanks, I can probably rig up a 500V supply (carefully) if needed. A 20VAC transformer backwards gets me there and more (assuming the transformer insulation can handle the voltage). Be VERY careful about doing that. Iron transformers have core & windings sized to start saturating near the 'work...
by ricardo
Mon Nov 02, 2015 7:24 pm
Forum: Pro Audio Design
Topic: Basic Mixer - 1646 output stage - seeking critique
Replies: 14
Views: 33781

Re: Basic Mixer - 1646 output stage - seeking critique

Any other reason for IC1b apart from restoring polarity? If not, you can omit it and just change polarity at the output of the 1646 _________________ You show all the 10k input mixing resistors grounded when that input is deselected. This means the mixing stage IC1a is operating at maximum noise gai...