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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 25th Nov 2017, 7:51 pm   #1
Levente
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Default Ferrograph Mono 1/2 track

Hey Guys,

It's been a while but hope all of you are well.

If any of you can advise on a symptom my tape recorder does, would be really awesome as I don't know what is happening.

Ferrograph Mono track.

All sounds fine, however, when I am recording a track and playing back, first 30 seconds of the recorded music is whining. After 30 seconds, all seems fine. I let the deck warm up for about 10 minutes before recording...and it does only at the very first recording, when I do another one or more, all sounding fine.

It seem that something needs some time to kick in during recording mode, and not sure what could that be...the large 0.1uF motor capacitor is still the old original Hunts. Could this be the issue?

Its not a major thing as after the first 30 seconds is OK, but it is bothering me not knowing what causing this.

Please let give me some hints or thoughts on this.

Thank you!
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Old 27th Nov 2017, 4:30 pm   #2
SteveCG
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Default Re: Ferrograph Mono 1/2 track

Levente,

What model of Ferrograph is it ?
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Old 27th Nov 2017, 5:02 pm   #3
Levente
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Default Re: Ferrograph Mono 1/2 track

hi Steve,

It is 4 but it is my guess only...it looks like Series 4 deck, as the amplifier section is custom made by someone called BTT and it's a Mullard design.

The unit is really sounding good, its just the first 30 second is whining when I record something...even tho it was switched on for 30 minutes before the recording took place...after this it worked fine...both on record and playback too.

It is weird..maybe nothing to do with the motor capacitor at all...that was only my guess...

Thanks!
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Old 27th Nov 2017, 5:38 pm   #4
BillDWVA
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Default Re: Ferrograph Mono 1/2 track

Hi Levente,

Have you got access to an oscilloscope and an external audio amplifier that you can temporarily connect up to the output(s) of the recording amplifier?

I would suggest checking with an oscilloscope that the bias oscillator is working properly when first switched to 'Record' and also that the output of the record amp is 'interfacing' correctly. You say it is not a standard Ferrograph circuit but there should be what is called a 'bias trap' in series with the record amp output (on the circuit it will be a tuned circuit consisting of a capacitor in parallel with a small choke, sometimes with a resistor and and capacitor in series) to stop the bias signal from saturating the audio amplifier. Be careful, the bias oscillator can generate quite high voltages in the wiring to the record head!

The bias oscillator will be running at a frequency of about 100kHz so is not audible but something is causing a 'modulation' that is your audible 'whining'.
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Old 27th Nov 2017, 5:56 pm   #5
Levente
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Default Re: Ferrograph Mono 1/2 track

Hi Bill,

Thanks for the advise. Its a bit of a "big fish" for me to do these tests, also not having an oscilloscope. I know it's a must have with these delicate gears, but sadly I don't have.

If the bias oscillator is not properly working would't be this whining permanent? It is going away after recording and playing for about 30 second-1 minute...just wondering..?

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Old 27th Nov 2017, 6:35 pm   #6
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Default Re: Ferrograph Mono 1/2 track

Levente. If you could make a recording of this whining and put it on You Tube or somewhere where we could hear it it would make it easier to diagnose the problem. 'Whining' can mean different things to different people. As you mentioned the motor I guessed your symptom was 'wowing' (speed variation) but others might have other ideas.
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Old 27th Nov 2017, 7:42 pm   #7
Hartley118
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Default Re: Ferrograph Mono 1/2 track

Is there an audible whine from the tape transport? I just wonder whether it's a mechanical issue and one of the head pressure pads is vibrating when everything is stone cold.

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Old 28th Nov 2017, 7:13 pm   #8
Levente
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Default Re: Ferrograph Mono 1/2 track

Hey Andrew/ Martin,

Andrew: will do a test in the next couple of days and a video. I am thinking also about one particular capacitor I did not change which is located under the Bias pot meter. When I refurbished this machine few months back, i hav changed all the old electrolytes caps, I did not touch the Philips mustard caps, however, there were a few of Wima bombs and other electrolytic s at the Bass/treble pots, gone bad....I remember, I have left one o.1uF cap at the bias, which was a black plastic casing cap...might this one also could be something to do with it?

Martin: thanks for your note. I have powered on the unit for 30 minutes before I did the test recording/run with these weird symptoms...machine itself was quiet warm...just don't understand that half of the song i have recorded did this moving/whining sound, like slowing down/speeding up motion evenly, then suddenly, at the half time of the song recorded, everything was fine.

Tape was a brand new sealed, 2012 year made "fresh" Quantegy..

thanks guys!
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Old 28th Nov 2017, 8:41 pm   #9
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Default Re: Ferrograph Mono 1/2 track

Is the tape shiney-back or matt-back? Should be shiney-back for a machine with pressure pads like the Ferrograph.
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Old 28th Nov 2017, 8:52 pm   #10
Levente
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Default Re: Ferrograph Mono 1/2 track

hi Graham, it looks like matt-back, brown front....Quantegy 407.
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Old 28th Nov 2017, 9:10 pm   #11
BillDWVA
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Default Re: Ferrograph Mono 1/2 track

Back-coated tapes sometimes 'squeal' as they pass through these Ferrograph decks, as has been said, they shouldn't really be used. Try a shiny tape; Maxell UD35 works well.
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Old 29th Nov 2017, 12:24 am   #12
jamesperrett
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Default Re: Ferrograph Mono 1/2 track

Quote:
Originally Posted by Levente View Post
hi Graham, it looks like matt-back, brown front....Quantegy 407.
It could be going sticky - I don't think Ampex/Quantegy ever really fixed their sticky shed problem so even the newer Quantegy tapes will be going sticky over the next few years if they aren't already.

There is a company called Recording The Masters in France who make tape according to the BASF formulations - their LPR35 tape might be more appropriate for a domestic machine.
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Old 30th Nov 2017, 4:38 pm   #13
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Default Re: Ferrograph Mono 1/2 track

A Series 4 Ferrograph uses pressure pads - and so should only be used with shiny backed tapes, as Llama has already said.
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