Quite interesting website Martin. Almost makes me want to learn German, but I fear my patience these days isn't what it used to be. For now I'll just look at the pictures
Post subject: Re: testing audio tubes for microphonics
Posted: May Fri 03, 2019 8:05 am
Member
Joined: Nov Wed 15, 2006 7:56 am Posts: 1421 Location: germany
I have designed and build that in the old style, using solding stripes and wires binding. As a experience. The plan what is where is the one and all, with the shortest possible connection. ( see Heathkit plans) The microphonic sensitive parts are the both microphone preamps, each with a EF86. The layout have a centered grounding at one point (negative out from PSU.). The most time is required for planing, the building is rather fast about the good plan. Martin
Post subject: Re: testing audio tubes for microphonics
Posted: May Fri 03, 2019 9:41 am
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Joined: Sep Thu 23, 2010 6:37 am Posts: 12437 Location: Powell River BC Canada
What I used to do with German tape recorders like the Uher Stereo Record 3 was to add a new bridge rectifier fed from the transformer winding the for the magnets needed to operate the record/play relays and the capstan seal-in.
That gave me 12 volts DC, to power the heaters of the EF86 tubes, and made a hum free machine.
_________________ de VE7ASO VE7ZSO Amateur Radio Literacy Club. May we help you read better. Steve Dow ve7aso@rac.ca
Post subject: Re: testing audio tubes for microphonics
Posted: May Fri 03, 2019 2:25 pm
Member
Joined: Mar Sun 31, 2019 3:44 am Posts: 126 Location: Alberta,Canada
this morning i went back and looked all the pictures. very nice work Martin. in 1979 i bought 2 sets of Canton speakers 1 pair of CT2000's and 1 pair of CT1000's 1 woofer in each is done and parts here are near impossible to find , but i am not giving up . Cheers Don