Search found 615 matches

by Gold
Mon Jul 08, 2019 12:15 pm
Forum: The Peabody Lounge
Topic: Entropy
Replies: 1137
Views: 420731

Re: Entropy

I'll find out Thursday whether the fuel stabilizer in the generator for the well pump worked. It hasn't been touched since November 2018. I know I'll need to clean the spark plug gap. Hopefully that will be it for emergency entropy. Hopefully there won't be too much more entropy on this trip. My mai...
by Gold
Tue Jul 02, 2019 11:28 am
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 298804

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

Here is the PV46SD line amp. This is my favorite era of Neumann design. The next era using the OA10 opamp doesn't sound as good and neither does the later IC based designs. The SP66 console I have uses them. The signal flow of the SP66 is PEV EQ-RV66 Attenuators-EE66-HT66 passive 12dB/oct HPF/LPF-PV...
by Gold
Mon Jul 01, 2019 5:43 pm
Forum: Pro Audio Design
Topic: Benchmark Mic Preamp from 1984 - Active Preamp History
Replies: 39
Views: 68829

Re: Benchmark Mic Preamp from 1984 - Active Preamp History

FWIW this was never considered a microphone preamp by Neumann. The PV76 was the microphone preamp. I have that schematic too. This was used post output fader on an SP172 for “relative disk level”. I’m sure it was used in their multichannel mixing consoles somewhere too. The tricked out line amp is t...
by Gold
Mon Jul 01, 2019 4:41 pm
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 298804

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

Ah, cool. Thanks!
by Gold
Mon Jul 01, 2019 3:22 pm
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 298804

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

mediatechnology wrote:
Mon Jul 01, 2019 3:03 pm
It's pretty much a transformer-based instrumentation amp.

I could see it used as a mic preamp, mix amp, cutterhead feedback amp or flat phono front end.
To use as a flat phono front end for an MM cart would you change C1 and C2 to be 23k5Ω resistors?
by Gold
Mon Jul 01, 2019 2:55 pm
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 298804

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

Wayne, It's just a flat amplifier with an available 26dB of gain. It was used as a generic amplifier in Neumann consoles of the era. There is a PV15, PV26 and PV46. They are not all the same circuit but they are all from the same design era. I actually thought it had an unbalanced front end from mem...
by Gold
Mon Jul 01, 2019 2:34 pm
Forum: Pro Audio Design
Topic: Flat Phono Preamp Based on John's P10 and 2SK389
Replies: 248
Views: 298804

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

I have about a dozen of these PV26b amps. It occurred to me these might make a good front end for the PTS. I thought I'd post a schematic and see if I'm totally off base or close.


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by Gold
Wed Jun 26, 2019 3:19 pm
Forum: Pro Audio Design
Topic: A Low Noise Balanced Input Moving Coil Preamp Using the ZTX851
Replies: 498
Views: 226781

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

After a quick comparison I think I like the sound of 100Ω loading better than 1KΩ. I came to a similar conclusion. I forget exactly how I have the DL103 terminated. Since I’m using a step up transformer the R source is transformed. I remember using a lower value than the manufacturers recommendatio...
by Gold
Mon Jun 24, 2019 12:27 pm
Forum: The Peabody Lounge
Topic: Entropy
Replies: 1137
Views: 420731

Re: Entropy

I drive a minivan so gas powered tools are banned from inside the cabin. I also like having a sword close by for any other types of emergencies.
by Gold
Mon Jun 24, 2019 10:45 am
Forum: The Peabody Lounge
Topic: Entropy
Replies: 1137
Views: 420731

Re: Entropy

We keep a Silky Saw Sugowaza in the car. It’s a Japanese tree saw that is amazing. For trees up to about 6” in diameter it is as fast as a chain saw. You never know when there is downed tree across the road. We took delivery of a shed to be used as the kitchen last May. Two of the windows were non f...