Search found 2252 matches

by JR.
Wed May 23, 2018 2:55 pm
Forum: The Peabody Lounge
Topic: RIP Joe Neil
Replies: 12
Views: 829

Re: RIP Joe Neil

I am almost reluctant to post because I did not know him, but I know a bunch of the same test equipment. I thought I was a pack rat, I see lots of old school heath kit and other brand old soldiers I used in the past.

Several iconic classics like that old HP sine wave generator 8-) .

JR
by JR.
Wed May 23, 2018 12:43 pm
Forum: Document
Topic: Audio Op Amp Shootout at Cycfi.com
Replies: 1
Views: 39

Re: Audio Op Amp Shootout at Cycfi.com

How did that Johnny Carson routine go... "everything we would ever want to know about op amps on one list" :lol:

JR
by JR.
Mon May 21, 2018 1:38 pm
Forum: Pro Audio Design
Topic: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 57
Views: 80341

Re: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp

I always wanted to fly a DC coupled A/D converter up with the DC coupled amp, then optically shift the digital output down to baseline. Maybe converter technology is stable enough to consider one(or more) converter footprints now? Or not.... 8-) BTW is the ZTX optimal for 150-200 ohm..? Reportedly s...
by JR.
Mon May 21, 2018 9:18 am
Forum: Build
Topic: Need help in choosing a amplifier IC for DIY home 2.1 speakers
Replies: 5
Views: 105

Re: Need help in choosing a amplifier IC for DIY home 2.1 speakers

The DIY Forum has three sections on amplifier building: Solid State http://www.diyaudio.com/forums/solid-state/ Chip Amp http://www.diyaudio.com/forums/chip-amps/ Class 'D' http://www.diyaudio.com/forums/class-d/ Something for every skill level and price point. I could waste a lot of time there.......
by JR.
Fri May 18, 2018 1:14 pm
Forum: Build
Topic: Need help in choosing a amplifier IC for DIY home 2.1 speakers
Replies: 5
Views: 105

Re: Need help in choosing a amplifier IC for DIY home 2.1 speakers

Maybe I'm just old and tired (I've designed amps before), but I bought some cheap small (3x stereo class A/B) amps to flesh out my living room home theater. Not much power (<20W ch) but loud enough for a quiet room. At some point I may cobble together some Hypex (class D) amp modules, They also make...
by JR.
Fri May 18, 2018 8:42 am
Forum: Document
Topic: Analog Devices "RFI Rectification Concepts" MT-096
Replies: 2
Views: 62

Re: Analog Devices "RFI Rectification Concepts" MT-096

well known but poorly understood... :lol:

JR
by JR.
Tue May 15, 2018 11:30 am
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 212
Views: 97181

Re: A Low Noise Balanced In Moving Coil Preamp Using the ZTX851

For one of my kit phono preamps using JFET inputs (P-10), I measured hundreds of JFETs in a fixture for Vgs with a nominal source resistor termination, then paired them up for closest Vgs match. They actually delivered lower THD in circuit when matched. Unexpected since the topology pretty much hold...
by JR.
Tue May 15, 2018 9:16 am
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 212
Views: 97181

Re: A Low Noise Balanced In Moving Coil Preamp Using the ZTX851

I apparently missed this the first time around.

One question.... at max gain, how much is the current density of the two input devices shifted apart? This might affect HF CMRR but this is picking a very tiny nit.

Nice circuit.

JR
by JR.
Mon May 14, 2018 3:03 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 212
Views: 97181

Re: A Low Noise Balanced In Moving Coil Preamp Using the ZTX851

Without thinking too hard, is there some way to servo that for good match?

JR
by JR.
Sat May 12, 2018 9:57 am
Forum: The Peabody Lounge
Topic: Entropy
Replies: 456
Views: 206711

Re: Entropy

The new PS is not UL listed :roll: but CE marked and also has the double insulated mark (box inside a box). I specifically bought one with a two wire line cord to get the double insulation. It is also plugged into a GFCI outlet so really unlikely to kill me. :o You obviously don't have one of the n...