[GreenKeys] Flecher TU170 signal levels?

[Harold Hallikainen]

On the input side, the TU-170 is pretty tolerant of wide levels since it
has a limiter. On the output side, there's a voltage divider to drop it
down to microphone level. My transceiver ( https://w6iwi.org/SEA245/ ) has
a 600 oh balanced "tri-state" line level interface between the transceiver
and multiple control heads. I added a transformer to the TU-170 with one
side of the transformer across the line and the other to the TU-170 input.
A reed relay connects the TU-170 output (before the above mentioned
voltage divider) to the transformer when in transmit.

Notes on the TU-170 are at https://w6iwi.org/rtty/tu170/ with a SPICE
analysis of the demodulator at https://w6iwi.org/rtty/tu170/spice/ .

Harold
https://w6iwi.org

On Fri, February 17, 2023 11:09 am, W2HX wrote:
> I think it isn’t so much a case of pre-dating line level, but more like
> who is the target audience for the device. The flesher type units were
> definitely consumer-grade items. And the consumer equipment would be less
> likely to have line level outputs and inputs. Hence reliance on speaker
> output level and frequently mic-input levels. However, if the audience is
> commercial or military there would be a much greater likelihood of having
> line-level equipment to interface with. That is my 2c take on the
> subject!
>
> From: greenkeys-bounces at mailman.qth.net
> <greenkeys-bounces at mailman.qth.net> On Behalf Of steve bennett via
> GreenKeys
> Sent: Friday, February 17, 2023 12:11 PM
> To: GREENKEYS BULLETIN BOARD <greenkeys at mailman.qth.net>
> Subject: Re: [GreenKeys] Flecher TU170 signal levels?
>
> Thanks to everyone who replied.
> I sort of suspected these devices pre-dated the use of "line level"
> signals.
>
> -Steve
>
> On Friday, February 17, 2023 at 11:34:36 AM EST, steve bennett via
> GreenKeys <greenkeys at mailman.qth.net<mailto:greenkeys at mailman.qth.net>>
> wrote:
>
>
> What are the Flecher TU170 signal levels?
> Is it compatible with "line level" signals like the ones used to
> interconnect stereo audio equipment?
> Or would you drive it from a headphone jack?
>
> Thanks,
> -Steve
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