EDAboard.com | EDAboard.de | EDAboard.co.uk | WTWH Media

curious symptom old Fisher stereo amp, inputs strange

Ask a question - edaboard.com

elektroda.net NewsGroups Forum Index - Repair Electronics - curious symptom old Fisher stereo amp, inputs strange

Goto page Previous  1, 2, 3


Guest

Wed Jan 09, 2019 8:45 pm   



On Tuesday, 8 January 2019 22:34:00 UTC, thekma...@gmail.com wrote:
Quote:
John-Del:

On a lot of receivers/amps(esp. older ones),
'Tape Out' does mean 'coming from' the
tape/cassette deck, and 'Tape In' means
what is going out of the receiver/amp to
the record deck.

From my own experience.


Other way round. Confusion can come from the fact that on a lot of amps the selected input is connected directly to the tape output*, thus one can always use 'tape output' as an unswitched input. I say always... some amps won't work this way since there are buffers in the way, and they don't pass signal backwards.

*Phono inputs are of course preamplified first.


NT


Guest

Wed Jan 09, 2019 9:45 pm   



tabb...@gmail.com wrote: "Other way round."

Nope. I hooked the thing up via literal interpretation, and
got no playback audio from tapes, and nothing recorded
to blanks.

Once I reversed them, like I said, everything worked as it
was expected to.

And as can be seen from Terry's testimony some posts back,
I'm not the only one experiencing gear labeled counterintuitively
to how it was supposed to be hooked up.

You weren't there in either of our cases, so you can't refute
either of our experiences.

Chuck
Guest

Wed Jan 09, 2019 9:45 pm   



On Tue, 8 Jan 2019 16:35:58 -0800 (PST), dansabrservices_at_yahoo.com
wrote:

Quote:
On Tuesday, January 8, 2019 at 6:07:32 PM UTC-5, thekma...@gmail.com wrote:
5:36 PMdansabr...@yahoo.com wrote:
"You have those backwards. On A RECENT receiver, the tape in
"comes from" the tape.
The tape out comes from the pre-amp section prior to the
volume control. "

See my edit(caps) above.

On older gear, pre-1980, the routing of
those ins and outs as I described them
stands. How do I know? Because I
assumed the same thing you stated
above, and got no audio! Once I
flipped both RCA pairs around, Voila,
everything was fine.

I won't argue your results, but with 35 years of repairing audio gear, I have not seen one yet that has that property. The in/out label on any gear is usually for that particular unit. The same exists on tape machines. There are input and output jacks there as well. The "output" jack on the tape should be activated when the tape is in play mode, thus is an output.
Me either. Audio-video tech for 30+ years.


John-Del
Guest

Thu Jan 10, 2019 12:45 am   



On Wednesday, January 9, 2019 at 3:30:16 PM UTC-5, thekma...@gmail.com wrote:
Quote:
tabb...@gmail.com wrote: "Other way round."

Nope. I hooked the thing up via literal interpretation, and
got no playback audio from tapes, and nothing recorded
to blanks.

Once I reversed them, like I said, everything worked as it
was expected to.

And as can be seen from Terry's testimony some posts back,
I'm not the only one experiencing gear labeled counterintuitively
to how it was supposed to be hooked up.

You weren't there in either of our cases, so you can't refute
either of our experiences.


No one is calling you a liar, but after nearly 50 years repairing consumer electronics as a career, I've never seen one wired like that. To me, this means the examples you cite are aberrations or at least a very small percentage of the units in service. They could have been wired that way intentionally or maybe the jacks or TM switch were miswired. It's also possible the rear panel was simply silk-screened incorrectly or a revised version was released with the previous version's back panel.

As I pointed out above, the other possibility is that the INs and OUTs were prefaced by "connect to", which changes the context entirely. I recall some low end packaged component systems that did not use universal nomenclature, but had connection "instructions" on the back panel (ie: connect to tape deck output).

Tim R
Guest

Fri Jan 11, 2019 3:45 pm   



MIDI in and out confuses me though.

I've never been able to get it to work except by trying it both ways.

Weird thing on this Fisher amp. Putting in headphones (and it's a 1/4 inch jack) disconnects speakers automatically. There's no way to have both room sound and headphone sound. Still it's nice to have this working again.


Guest

Fri Jan 11, 2019 3:45 pm   



On Friday, January 11, 2019 at 9:26:30 AM UTC-5, Tim R wrote:
Quote:
MIDI in and out confuses me though.

I've never been able to get it to work except by trying it both ways.

Weird thing on this Fisher amp. Putting in headphones (and it's a 1/4 inch jack) disconnects speakers automatically. There's no way to have both room sound and headphone sound. Still it's nice to have this working again.


This is a very common setup. I have received units with no sound that turned out to be a failure of the headphone jack. Without the headphones, the jack shorts the signal line to allow it to continue to the amp. If the jack does not short, then no sound. Rare, but I have seen it a number of times over the years.


Guest

Fri Jan 11, 2019 7:45 pm   



Tim R:

Are there buttons or switches on that Fisher amp
for selecting pairs of speakers?

Tim R
Guest

Sun Jan 13, 2019 1:45 pm   



On Friday, January 11, 2019 at 12:45:21 PM UTC-5, thekma...@gmail.com wrote:
Quote:
Tim R:

Are there buttons or switches on that Fisher amp
for selecting pairs of speakers?


Yes.
There are two sets of speaker outputs, the A and the B.
There is a little square pushbutton, marked out for A and in for B.
With the headphone inserted, there is no sound from A whether the button is in or out. I've never put speakers on B so I've not tested that set.

Apparently you can't use two sets of speakers at the same time, or one set plus headphones. That seems curious to me. My other stereo amps don't work that way. But I'm not complaining, this little amp is perfect for what I use it for, a portable amp to get sound from a laptop I bring to various places.

John-Del
Guest

Sun Jan 13, 2019 4:45 pm   



On Sunday, January 13, 2019 at 7:09:40 AM UTC-5, Tim R wrote:
Quote:
On Friday, January 11, 2019 at 12:45:21 PM UTC-5, thekma...@gmail.com wrote:
Tim R:

Are there buttons or switches on that Fisher amp
for selecting pairs of speakers?

Yes.
There are two sets of speaker outputs, the A and the B.
There is a little square pushbutton, marked out for A and in for B.
With the headphone inserted, there is no sound from A whether the button is in or out. I've never put speakers on B so I've not tested that set.

Apparently you can't use two sets of speakers at the same time, or one set plus headphones. That seems curious to me. My other stereo amps don't work that way. But I'm not complaining, this little amp is perfect for what I use it for, a portable amp to get sound from a laptop I bring to various places.


To further complicate things, I remember working on some cheaper amps that would put the A speakers in series with the B speakers if both A and B were selected so as not to kill the outputs with too low impedance. So if you had a pair of speakers on A and nothing on B, pushing the B would kill all sound. Used to get a few nuisance calls over that.


Guest

Sun Jan 13, 2019 9:45 pm   



Tim R:

Since there are speaker selectors then the speakers, in theory,
should not be canceled by plugging in headphones. On my 1990s
era JVC receiver, I have to remember to deselect all speakers
when listening via headphones, or I'll still be sharing what I'm
listening to with the wife - or the neighbors...! And speakers on
buss A, B, or both can still be driven with it while listening to
headphones, so I have to remember to select them out.

Sounds like yours has got some serious main board(motherboard to
us PC geeks) issues, or soldering issues.

Tim R
Guest

Mon Jan 14, 2019 4:45 am   



On Sunday, January 13, 2019 at 3:23:25 PM UTC-5, thekma...@gmail.com wrote:
Quote:
Tim R:

Since there are speaker selectors then the speakers, in theory,
should not be canceled by plugging in headphones. On my 1990s
era JVC receiver, I have to remember to deselect all speakers
when listening via headphones, or I'll still be sharing what I'm
listening to with the wife - or the neighbors...! And speakers on
buss A, B, or both can still be driven with it while listening to
headphones, so I have to remember to select them out.

Sounds like yours has got some serious main board(motherboard to
us PC geeks) issues, or soldering issues.


Well, I dunno about that.
Most equipment I've had if the headphone jack was 1/8, it would disconnect speakers, and if 1/4, not.
But looking at this CA-400, I can only select A or B speakers. I can't choose none. So it makes sense that the headphone would disconnect them. Maybe it's working properly.


Guest

Mon Jan 14, 2019 5:45 am   



Tim R:

My old 1980s Sears one-piece Tuner/Phono/Cassette
had 1/4" headphone out, and it cancelled the speakers
when I plugged cans into it, just as the 1/8" on my
later bookshelf CD/Tuner/Aux.

That Fisher though sounds like one of a kind!

Chuck
Guest

Mon Jan 14, 2019 5:45 pm   



On Sun, 13 Jan 2019 19:00:48 -0800 (PST), Tim R <timothy42b_at_aol.com>
wrote:

Quote:
On Sunday, January 13, 2019 at 3:23:25 PM UTC-5, thekma...@gmail.com wrote:
Tim R:

Since there are speaker selectors then the speakers, in theory,
should not be canceled by plugging in headphones. On my 1990s
era JVC receiver, I have to remember to deselect all speakers
when listening via headphones, or I'll still be sharing what I'm
listening to with the wife - or the neighbors...! And speakers on
buss A, B, or both can still be driven with it while listening to
headphones, so I have to remember to select them out.

Sounds like yours has got some serious main board(motherboard to
us PC geeks) issues, or soldering issues.

Well, I dunno about that.
Most equipment I've had if the headphone jack was 1/8, it would disconnect speakers, and if 1/4, not.
But looking at this CA-400, I can only select A or B speakers. I can't choose none. So it makes sense that the headphone would disconnect them. Maybe it's working properly.
It is. A very common configuration.



Guest

Tue Jan 15, 2019 5:45 am   



>"I won't argue your results, but with 35 years of repairing audio gear, I have not seen one yet that has that property. The in/out label on any gear is usually for that particular unit. The same exists on tape machines. There are input and output jacks there as well. The "output" jack on the tape should be activated when the tape is in play mode, thus is an output. "

That has not been my experience. In most amps the tape output is pretty much at the output of the input selector, or in the case of a Yamaha for example, form another separate selector. As such it can be backfed.

If it is buffered or even resistor isolated that will not work so well, but it seems the engineers decided that the low output impedance as worth it to keep the noise down. As such, not only can it be backfed, it can also be shorted by the wrong thing connected and cause no output. I got this DCD Pro CD player, commercial, like DJ model. I had it temporarily hooked up wrong because I couldn't really see in the back, it was going IN to the tape OUT. Well when the CD player was shut off it apparently shorts the outputs and that resulted in no sound from any source.

In another case I had a VHS HIFI, a Sanyo VCR-7200 that when turned off got non linear at the record INPUTS. It caused severe distortion unless it was turned on. It is easy to figure out why, the input stage was probably diode protected against overvoltage and when the power supply dropped, the shunting was to zero volts.

It is a piece of wire, the "current" can go both ways.

I didn't mention it before I think, but some of those units used a TC9164 or something as a selector chip and those did go bad. I had to change a bunch of them back when. That was how they were - the tape output was the only "input" that would work.

What I don't remember is if those chips fed a CMOS switch set or had it onboard. Like 4066s, or the cheaper one, 4016 ? Whatever.

I could probably find a print and find out but why don't you just to it ? Right from Google you got Electrotanya, and then there is hifiengine and hifimanuals. You need a membership to the latter two but they don't charge, they don't spam or any of that. I got nothing but good to say about those sites.

If you need the TC9164 they are out there. I have just Googled it and it seems they do have the actual switches onboard.

I know that amp is considered BFC by audiophiles but that series of amps is not bad. The circutry is fine, low distortion, all that. Anything the audiophools don't hear in it is their own problem. The only problem is they are underbuilt, for someone like me. I mean I will work it into 2.3 ohms n shit, they don't like that, they get too hot. That's why I don't use one, but for normal human beings the are OK.


Guest

Tue Jan 15, 2019 5:45 am   



>"But I'm wondering if the tape mon connections are simply labelled "in" and "out", or if they're preceded by "connect to"... "

I can't stand shit like that. Just say it, output or input, not what you connect it to.

Goto page Previous  1, 2, 3

elektroda.net NewsGroups Forum Index - Repair Electronics - curious symptom old Fisher stereo amp, inputs strange

Ask a question - edaboard.com

Arabic version Bulgarian version Catalan version Czech version Danish version German version Greek version English version Spanish version Finnish version French version Hindi version Croatian version Indonesian version Italian version Hebrew version Japanese version Korean version Lithuanian version Latvian version Dutch version Norwegian version Polish version Portuguese version Romanian version Russian version Slovak version Slovenian version Serbian version Swedish version Tagalog version Ukrainian version Vietnamese version Chinese version Turkish version
EDAboard.com map