Search found 522 matches

by Gold
Fri May 17, 2019 11:49 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 110
Views: 96064

Re: Phono Transfer System Construction Information

For MM noise is not an issue (interference of course still can be). I've found that in NYC at least even a couple of feet of unbalanced cable on an MM cartridge picks up quite bit of crud. A balanced front end goes a long way. A DL103 with a transformer front end into the MM preamp was quieter by a...
by Gold
Fri May 17, 2019 10:43 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 110
Views: 96064

Re: Phono Transfer System Construction Information

I think the main reason to locate the preamp at the turntable is noise. One of the reasons I’m sticking with a step up transformer into the MM preamp for a DL103 is for the transformer CMRR and galvanic isolation.
by Gold
Wed May 15, 2019 10:07 am
Forum: Build
Topic: Mid Side M-S Matrix Construction Information
Replies: 112
Views: 204617

Re: Mid Side M-S Matrix Construction Information

I took another look at the MSII. I have a pile of the original MS boards so I didn’t look to closely at this. The switching options are fantastic. I’ve been trying to cobble together what this does with the original boards for my monitor controller. This takes care of all the options I want. Then th...
by Gold
Sat Apr 27, 2019 7:21 pm
Forum: Test, Measurement and Repair
Topic: HP3582A
Replies: 3
Views: 189

Re: HP3582A

Seems like I should probably sell it. Since it is good with very low frequencies I thought it might be useful for looking at turntable rumble and tape machine flutter. Those are more curiosities than anything else. I’m not planning on designing turntables or tape machines. I suppose it would be good...
by Gold
Fri Apr 26, 2019 12:56 pm
Forum: Test, Measurement and Repair
Topic: HP3582A
Replies: 3
Views: 189

HP3582A

I bought an HP3582A many years ago as I was just getting started building my console. I didn't have enough experience to use it when I got it. It has been sitting on a shelf ever since. I'm doing a spring cleaning and selling stuff I don't need and will never use. The input section looks like it nee...
by Gold
Fri Apr 26, 2019 12:48 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 441
Views: 155433

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

Looks good Wayne. I think my DL103 into your MM preamp with a Lundahl 1:8 stepup is about the same. I don't have FFT setup yet so I can't quite do an apples to apples comparison. I've been quite happy with this setup. I think I have a resonance around 10K. I underdamped the cartridge because to it s...
by Gold
Thu Apr 11, 2019 5:42 pm
Forum: Test, Measurement and Repair
Topic: entropy continued?
Replies: 34
Views: 2254

Re: entropy continued?

Umm, I got it wrong. I replaced the IC sockets and nothing changed. A real head scratcher. It turned out to be a general power issue. My power arrangement is a little more complicated than most. I use an 8 pole Buckaneer 400 series connector for power. I run separate wires for Audio Common and Chass...
by Gold
Tue Apr 09, 2019 5:28 pm
Forum: Test, Measurement and Repair
Topic: entropy continued?
Replies: 34
Views: 2254

Re: entropy continued?

Today one of the four opamps wasn't happy even with the Stabilant 22. I think I'm just going to replace the socket. This board must have been exposed to some debris. Maybe dust from a cutoff wheel? The other three boards aren't doing this. I should just replace all four sockets for good measure.
by Gold
Tue Apr 09, 2019 9:26 am
Forum: Test, Measurement and Repair
Topic: entropy continued?
Replies: 34
Views: 2254

Re: entropy continued?

billshurv wrote:
Tue Apr 09, 2019 3:29 am
How are you bending the IC leads before insertion?

I usually give the IC a small squeeze. Then I fit the IC pins in one side of the socket and bend the other side until it fits in the socket.

Is there a better way?
by Gold
Mon Apr 08, 2019 6:41 pm
Forum: Test, Measurement and Repair
Topic: entropy continued?
Replies: 34
Views: 2254

Re: entropy continued?

I'm working on getting the second T-Filter EQ going. Everything was going smooth until I loaded the first filter boards with IC's. When I powered it up the positive going half of the sine wave was coming up flat topped. After about five seconds the top half of the waveform would come up and look nor...