Search found 17 matches

by Bill Wilson
Wed Nov 27, 2019 5:08 pm
Forum: Pro Audio Design
Topic: Benchmark Mic Preamp from 1984 - Active Preamp History
Replies: 39
Views: 64319

Re: Benchmark Mic Preamp from 1984 - Active Preamp History

Sorry Wayne: I had forgotten I was on the wrong forum. It can be found on <Groupdiy.com> Look at the technical forum for Neotek, it is either the last or next to last post. By carefully matching the resistors around the discrete transistors on the front end; the CMRR approaches 100 db. I used 5% car...
by Bill Wilson
Sun Nov 24, 2019 10:41 pm
Forum: Pro Audio Design
Topic: Benchmark Mic Preamp from 1984 - Active Preamp History
Replies: 39
Views: 64319

Re: Benchmark Mic Preamp from 1984 - Active Preamp History

Paul Buff brought out his Transamp around 1975. In 1977 I was service mgr. for the Nashville MCI dealer. I met with Paul at Quadraphonic Studio; where we installed a Transamp in place of one summing amplifier, as a test toward improving the noise figure in the MCI 500 series console. It did provide ...
by Bill Wilson
Tue Mar 05, 2019 7:16 am
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 283689

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

No Wayne: The 103R cartridge sees a resistive load of 1.6k. As moving coil cartridges are almost universally flat in their response it makes little sense to try & load it with a low resistance. The 1.6k is made up of 2ea, 802 ohm 1/4w metal foils that also provide the necessary ground reference need...
by Bill Wilson
Mon Feb 11, 2019 3:49 pm
Forum: Test, Measurement and Repair
Topic: Heathkit IM-5238 AC Voltmeter Repair
Replies: 2
Views: 2260

Re: Heathkit IM-5238 AC Voltmeter Repair

I have a pair of these I built in 1978; when I went into studio equipment repair in Nashville. i have never had a problem with them other than a sticking meter movement. The meters were made by Dixon & I was able to find a replacement at Sky Craft in Orlando. Simply swapped scales & 8nstalled it. I ...
by Bill Wilson
Wed Jun 20, 2018 5:21 pm
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 283689

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

Yes Wayne it is the Preamp that Joe Neil did the pcb layout. The 103R is not retipped it is a slightly better cartridge. Some of the users that use mike xfmrs. for stepup claim it is as good as any in the up to $1000- range. I had talked to an applications engr. at That & designed a low Z resistive ...
by Bill Wilson
Mon Jun 18, 2018 10:23 pm
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 283689

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

Hi Wayne: Thought I would jump in with my two cents. I designed my own moving coil phono preamp, using either That 1510 or AD SSM2019 mike pres. for the balanced input. I based the design around Denons 103R M/C cartridge. The preamp gain is set for 1000 times; as the output from the 103R is 280 micr...
by Bill Wilson
Thu May 31, 2018 1:20 pm
Forum: Pro Audio Design
Topic: A new way to produce lettered front panels
Replies: 3
Views: 2308

Re: A new way to produce lettered front panels

For my initial front panel overlay, I used MS Word to print the lettering; also had to figure the placement of the controls. Then used a program named "Zamzar" to convert the file to one accepted by the sign shop. Now I am doing each control separately using 1. print, 2. cut & paste. Next take to th...
by Bill Wilson
Wed May 30, 2018 4:12 pm
Forum: Pro Audio Design
Topic: A new way to produce lettered front panels
Replies: 3
Views: 2308

A new way to produce lettered front panels

My local sign shop in the Tampa Bay area, introduced me to a company by the name of "Rowmark". They produce plastic sign material in both 1/32" & 1/16" thickness. The material comes in many different colors & is laser engraveable. Wayne asked me to share this method after seeing the results. You can...
by Bill Wilson
Thu May 24, 2018 5:36 pm
Forum: The Peabody Lounge
Topic: RIP Joe Neil
Replies: 13
Views: 6262

Re: RIP Joe Neil

I am stunned! I first met Joe in Feb. 1978. He was chief engineer at Bob Richardsons studio, just off I75 in Atlanta. I was service mgr. for the MCI Nashville dealer & was there to tune the eq on the control room monitors. We hit it off right from the start. We rekindled our friendship 2 yrs. ago. J...
by Bill Wilson
Mon Dec 28, 2015 1:24 am
Forum: Document
Topic: TI Parts Going End of Life
Replies: 20
Views: 27140

Re: TI Parts Going End of Life

Another TI part now listed by Mouser at end of life for the dip8 package, LME 49860. It will still be available in SOIC. Only problem is I do not want to go SMT as yet. It is the only one in the series to run on +- 22vdc.