Neumann SM-2 work, various noises and wiring.

Mostly assembled EAPreq 500 series preamp prototype.

Greg wrote: Fri Sep 29, 2023 12:35 pm
Mostly assembled EAPreq 500 series preamp prototype.

Ooh, that sounds interesting. Is it based on any kind of lineage/similar to any well known circuits?

losthighway wrote: Fri Sep 29, 2023 1:23 pm

Greg wrote: Fri Sep 29, 2023 12:35 pm
Mostly assembled EAPreq 500 series preamp prototype.

Ooh, that sounds interesting. Is it based on any kind of lineage/similar to any well known circuits?

Based off our preamp.. This is something that's taken me too long to get on. Thankfully friends lit a fire.

Greg wrote: Fri Sep 29, 2023 12:35 pm... EAPreq 500 series preamp prototype.

Very exciting!

Greg wrote: Thu Oct 05, 2023 10:57 pm

losthighway wrote: Fri Sep 29, 2023 1:23 pm

Greg wrote: Fri Sep 29, 2023 12:35 pm
Mostly assembled EAPreq 500 series preamp prototype.

Ooh, that sounds interesting. Is it based on any kind of lineage/similar to any well known circuits?

Based off our preamp.. This is something that's taken me too long to get on. Thankfully friends lit a fire.

Are you selling those? Love my Mid-side matrix.

Mickey242 wrote: Mon Oct 09, 2023 10:05 pm

Greg wrote: Thu Oct 05, 2023 10:57 pm

losthighway wrote: Fri Sep 29, 2023 1:23 pm

Ooh, that sounds interesting. Is it based on any kind of lineage/similar to any well known circuits?

Based off our preamp.. This is something that's taken me too long to get on. Thankfully friends lit a fire.

Are you selling those? Love my Mid-side matrix.

Pretty soon, yeah. Just need to get some of the unfun stuff done. (packaging, pricing, pricing)...
Glad you're liking the Matrix!

Repaired a Neumann SM-2 mic cable. The thicker filament wire busted somewhere near the end of the cable. This end always had a weird twisted look to the jacket, like it spent a long time coiled under stress decades ago. Anyway, I found a spot that if I massaged I could bridge the open connection. I cut the cable back clear of that and reattached the connector. The other end had a dent in the threaded collar, so I replaced that, while I was at it. This might have to do with some reported intermittent behavior with the SM-2s...

More work on the EApreq500 module.

This that and the other...

Various Neumann SM-2 work related to minimizing noise.

EApreq500 work.

Neumann SM-2 #585

Trying out two Phædrus AC701 replacement amps. We have four SM-2 bodies and three capsule assemblies. The noisiest SM-2 was volunteered for the experiment. So far soooo quiet and nice. I can't wait to try it out next to a stock mic in session.

-Elsewhere-

Studer A820MCH reel motors go limp after hours of operation.

Found overheated section of the Power Fail Sense board, including a rough repair.
I upgraded Power Fail Sense board to latest version (820.869.81), which cools down its operation and allows for a little more forgiving sense of the ±15v rail values.
It is possible that heat build up with the machine in an unventilated corner is causing other issues, which could lead to a logic controlled shutdown.
Previous unsuccessful attempts to trouble-shoot this problem were -
Replacing the relay on the Power Fail Sense Board, whose plastic case was missing, exposing the contacts to the elements.
Exercising all connections between the motor control, and Tape Deck motherboard
Swapping the Spooling Motor Controller and Drive boards with known working ones.

Testing/finishing 10 more DI boxes.
Working on power supply pcb layout for tube mics.
EApreq500 work.