Search found 559 matches

by Gold
Tue Jul 16, 2019 11:47 am
Forum: The Peabody Lounge
Topic: Entropy
Replies: 957
Views: 351554

Re: Entropy

The new batteries worked. I need to try charging the set I removed to see if the battery charger is working or not. I'm now investigating installing solar panels to charge the batteries. When I was first getting going the batteries needed to work without exception. I couldn't take the chance of arri...
by Gold
Tue Jul 09, 2019 6:35 pm
Forum: The Peabody Lounge
Topic: Entropy
Replies: 957
Views: 351554

Re: Entropy

AGM or glass matt is a sealed battery. Lead acid are unsealed and need maintenance. You have to keep water in the battery. Lead acid also corrode so you have to keep the terminals clean. There is outgassing with lead acid so they are not suitable for indoor use. I got the new batteries. They come fu...
by Gold
Tue Jul 09, 2019 2:13 pm
Forum: The Peabody Lounge
Topic: Entropy
Replies: 957
Views: 351554

Re: Entropy

did you search this..? there might be some way to resurrect a sick/dead battery... I found a few but don't know what battery technology you are dealing with. JR PS: From watching too many cowboy movies as a kid, bushwhacking, meant to ambush somebody. It looks like there is no way to resurrect them...
by Gold
Mon Jul 08, 2019 4:34 pm
Forum: The Peabody Lounge
Topic: Entropy
Replies: 957
Views: 351554

Re: Entropy

I tried to charge the solar batteries today to bring to the mountains. They wouldn't charge. After doing a bit of searching I think I have only myself to blame. I let them sit depleted for nine months. It seems a 70% charge is best for long term storage and preserving battery life. It's going to be ...
by Gold
Mon Jul 08, 2019 12:15 pm
Forum: The Peabody Lounge
Topic: Entropy
Replies: 957
Views: 351554

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: 269146

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: 35
Views: 60215

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: 269146

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: 269146

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: 269146

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...