Search found 15 matches

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: 239
Views: 264194

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: 1418

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: 239
Views: 264194

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: 239
Views: 264194

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: 1860

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: 1860

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: 5202

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: 25704

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.
by Bill Wilson
Mon Mar 16, 2015 10:23 am
Forum: Pro Audio Design
Topic: Limiters with optocouplers
Replies: 48
Views: 93537

Re: Limiters with optocouplers

Go online at Rolls Audio; look up the manual for the 422 field mixer. You will find a limiter implementation using vactrols & also low freq. cut on the output of their transformer less mike preamps.
by Bill Wilson
Mon Mar 16, 2015 10:19 am
Forum: Pro Audio Design
Topic: Voltage follower for high-pass
Replies: 11
Views: 21144

Re: Voltage follower for high-pass

Hi Carlmart: The simplest way to get some low freq. roll off would be to have 2 values of coupling caps at the output of the 1510 mike pre; one to give flat response down to approx. 30 hz & another that rolls off the low end at 6db per octave starting the roll off at 150hz. This is the method used b...