Search found 5494 matches

by mediatechnology
Sat May 25, 2024 12:11 pm
Forum: Pro Audio Design
Topic: More work for the wizard
Replies: 5
Views: 248

Re: More work for the wizard

Yes something like that... with the sleeve driven L+R the left output was driven with L-R so they combined to cancel out the R. Alternately the right output was driven with R-L so the left cancelled out. JR That sounds right and you end up with 2L and 2R which doubles your voltage swing and squares...
by mediatechnology
Sat May 25, 2024 10:33 am
Forum: Pro Audio Design
Topic: More work for the wizard
Replies: 5
Views: 248

Re: More work for the wizard

Back in the 80s I designed a headphone amp while at Peavey (the HB-1) that drove the sleeve with opposite polarity to generate 2x the voltage output from +/-15v rails. I designed it after hearing how loud a drummers headphone mix was during a session. 8-) JR So if I were to guess the sleeve was dri...
by mediatechnology
Sat May 25, 2024 6:23 am
Forum: Pro Audio Design
Topic: More work for the wizard
Replies: 5
Views: 248

Re: More work for the wizard

Thanks for the input Magnus! I think there may be two reasons for balanced headphone wiring. The first is to provide extra voltage swing for hard-to-drive-phones. The second is to avoid the shared I*R drop in the TRS sleeve connection. The I*R drop in the common sleeve connection reduces the Mid com...
by mediatechnology
Mon May 20, 2024 1:43 pm
Forum: Build
Topic: Quadrature Summing Filter Construction Information
Replies: 2
Views: 22670

Re: Quadrature Summing Filter Construction Information

Updated the board (QSF_4), schematic and BOM to add 22 pF compensation caps to use NJM2068, LM833, 4558 and other PNP op amps having a >750 kHz peaking response. The are not needed for the TL072, NE5532 or OPA2134.
by mediatechnology
Sun May 19, 2024 9:38 am
Forum: The Peabody Lounge
Topic: Gerber Text File Editing Fun
Replies: 5
Views: 573

Re: Gerber Editing Fun

I set aside this editing project for a couple of weeks while I soldered boards and dealt with the usual yard, household and auto entropy. The remaining Gerber Fun task was to move the Left channel "G" character 25 mils west. (Actually 24 mills to match the Right.) As you can see I got it d...
by mediatechnology
Fri May 17, 2024 7:12 pm
Forum: Pro Audio Design
Topic: Using The TI PCM4222 A/D Evaluation Module
Replies: 27
Views: 35701

Re: Using The TI PCM4222 A/D Evaluation Module

Glad you were able to put it to work!

I use 96 kHz since I primarily use it for test and measurement and occasionally for RAW (flat) vinyl capture.
by mediatechnology
Mon May 06, 2024 11:11 am
Forum: The Peabody Lounge
Topic: Gerber Text File Editing Fun
Replies: 5
Views: 573

Re: Gerber Editing Fun

I've used the Ucamco viewer and file checker. They're a great resource. Code for D21 defines a 0.065 x 0.065 pad: %AD D21 R,0.065X0.065*% The entire thermal pad, bottom layer, is 5 objects total. Square pad of 0.065X0.065 And four identical square polygons of 36x37 mils of negative polarity keep-out...
by mediatechnology
Mon May 06, 2024 10:38 am
Forum: The Peabody Lounge
Topic: Gerber Text File Editing Fun
Replies: 5
Views: 573

Re: Gerber Editing Fun

Thanks! Not sure I'm brave or just crazy. I've been using Gerbv : https://sourceforge.net/projects/gerbv/ and GerberLogix : https://easylogix.de/products_detail.php?prog_id=1 Every layer, except the .oln outline layer, requires modification. Top and bottom copper, top and bottom silkscreen, top and ...
by mediatechnology
Mon May 06, 2024 6:39 am
Forum: The Peabody Lounge
Topic: Gerber Text File Editing Fun
Replies: 5
Views: 573

Gerber Text File Editing Fun

I just sent off a revised layout to ExpressPCB that I had "stretched" 0.2 inches to add some additional compensation caps. The previous layout worked fine when reasonable op amps were used but peaky 4558-class op amps such as the NJM2068, LM833, MC33078 and NJM45XX-series were problematic....
by mediatechnology
Sun May 05, 2024 6:41 am
Forum: Build
Topic: Mastering Stereo Insert Switcher with Flip Construction Information
Replies: 33
Views: 118847

Re: Mastering Stereo Insert Switcher with Flip Construction Information

Who made that unit? I'd love to send them referrals. Have seen similar on Reverb. If you have contact info that would be great. I may be able to refer other custom work to them. Hi, i am new here, and i won`t be able to DIY a Mastering Insert Switcher, that is why i would like to buy one of these l...