Search found 19 matches

by crin
Mon Jul 26, 2021 10:24 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 227
Views: 254308

Re: Phono Transfer System Construction Information

since i don't know which model of A80 you're talking about, i have put all Studer A80 repro amp schematics from the service manuals i could find as PDFs on my server: A80 R A80 RC mk I and mk II A80 VU Mk I A80 VU Mk II … Mk IV i think the schematic you're looking for is in the A80 VU Mk II … IV fil...
by crin
Tue Jun 29, 2021 7:30 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 227
Views: 254308

Re: Phono Transfer System Construction Information

i think i heard somewhere sometime that the VU bridge is the culprit. wasn't it that the non-VU A80s hat low-Z heads and that for the the VU-machines, studer had to develop new high(er)-Z heads? and could it be that you can't put a VU bridge on a machine that didn't have one ex-factory – and on the ...
by crin
Mon Mar 01, 2021 7:59 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 227
Views: 254308

Re: Phono Transfer System Construction Information

I have to say I am enjoying the fact that this breaks nearly every rule that audiophools hold dear and still works superbly. do you consider douglas self one of these audiophools, too? :D after all, he is staunchly opposed to balanced phono preamps. they are noisier than a single ended circuit – an...
by crin
Thu Jan 28, 2021 5:36 am
Forum: Test, Measurement and Repair
Topic: how to test relays for phono signals
Replies: 15
Views: 40109

Re: how to test relays for phono signals

crin wrote: ↑ is there a particular reason why you suggest the 1510 instead of the 1512? The datasheet is clear. Here high gain is needed. that's what puzzles me. according to the data sheets, both chips provide up to 60 dB of gain. the only difference i can see WRT gain is that the 1510 is specifi...
by crin
Wed Jan 27, 2021 9:46 pm
Forum: Test, Measurement and Repair
Topic: how to test relays for phono signals
Replies: 15
Views: 40109

Re: how to test relays for phono signals

The 1 K Rbias might not be enough. With the concern being the low levels of MC switching pick 10-100Ω. If the relay load resistor is 100Ω then you only need 2 mV of common mode voltage at the input to the diff amp to produce a contact current of 20 µA. not sure i understand you – are you suggesting...
by crin
Tue Jan 26, 2021 10:30 am
Forum: Test, Measurement and Repair
Topic: how to test relays for phono signals
Replies: 15
Views: 40109

Re: how to test relays for phono signals

i'm trying to figure your proposed null test with gain – would you place the inputs of the 1512 at C and NC and measure what comes out after 60 dB of amplification? but if there's no signal, how can it be distorted? but the idea of a null test has a lot of appeal. i'm still trying to figure out if t...
by crin
Mon Jan 25, 2021 10:53 am
Forum: Test, Measurement and Repair
Topic: how to test relays for phono signals
Replies: 15
Views: 40109

Re: how to test relays for phono signals?

i have the boost stages (waynes flat MM preamps), and i could also use the inverse RIAA filter to create a RIAA emphasized signal. but what kind of signals do i use, what kind of "error" could a relay possibly cause? one thing is the outgassing of plastic and environmental pollution seeping in throu...
by crin
Fri Jan 22, 2021 7:48 pm
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 227
Views: 254308

Re: Phono Transfer System Construction Information

somehow, this board looks familiar… :lol: reminds me of east texas: sparsely populated :mrgreen:
by crin
Fri Jan 22, 2021 7:34 pm
Forum: Test, Measurement and Repair
Topic: how to test relays for phono signals
Replies: 15
Views: 40109

how to test relays for phono signals

i'm looking for suggestions on how to test relays for use at phono (MM) levels: how to set up the test for repeatable results, what signals to use to detect measurable differences, what to look for etc. background: i'm building a flat phono preamp with several of wayne's MM and MC boards, various in...
by crin
Mon Sep 07, 2020 11:36 am
Forum: The Peabody Lounge
Topic: US Postal Service Air/Sea Shipment Diversion
Replies: 12
Views: 35021

Re: US Postal Service Air/Sea Shipment Diversion

a feast for dumpster divers… :D do they still put cheques in the mail in the US?

(good observation re the time of the crime. the shadows look more like 7-/8-ish. i think they made pre-dawn illegal a long time ago.)