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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 21st Aug 2019, 7:31 pm   #1
Amraduk
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Default Fidelity Playmaster/Braemar Tape Recorder

A friend of mine has a Braemar tape recorder and wants to connect it to his computer so he can copy his tape recordings.

According to the 1969-1970 issue of the R+TV servicing book there is a monitor output which gives 400mV at 2K. Looking at the circuit diagram shows this output is connected to the anode of V1b (ECC83) via a 100K resistor and a 0.05uF capacitor.

If my arithmetic is right, that would give a signal of about 20 volts at the anode of V1b but it is dependant on the setting of the volume control. Does this sound about right? If so, then I presume that connecting it to the computer's line input with approx 10K input impedance would be satisfactory?

Regards,

Dave.
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Old 22nd Aug 2019, 2:25 pm   #2
Edward Huggins
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

A "Monitor" output on these types of machines is usually independent of the recorder's volume control - i.e. a flat output of c.200/350mV - and is also usually nowhere near any anode.
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Old 23rd Aug 2019, 12:07 pm   #3
ricard
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

The OP did say that the circuit diagram shows the output connected to an anode via 100k.

Connecting to a 10k input would give roughly a 1:10 potential division, so about 2 volts which should be a reasonable level for a line input. I bit worried about the loading on the anode, as the anode resistor will also be in the 100k region, but I'm thinking that the worst result would be the lowering of the signal level to about half, so 1 volt which should also be ok.
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Old 23rd Aug 2019, 12:28 pm   #4
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

0.05 sounds like paper, worth a check!
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Old 23rd Aug 2019, 9:39 pm   #5
Amraduk
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

@ Edward

The volume control is between V1a and V1b (ECC83) and the Monitor O/P is taken from V1b anode, so the volume control will affect the Monitor O/P.

@ ricard

The information in the R+TV service book says: "Monitor output: 400mV at 2k." With a 10K load instead, the output will of course be higher, in this case, assuming that 20V at the anode of V1b is 20V (is that about right?), it will be about 1.8V. I would think that the loading on V1a would have been taken into account at the design stage.

Many thanks for every ones comments.

Regards,

Dave.
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Old 23rd Aug 2019, 10:02 pm   #6
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

The Fidelity Braemar is electrically identical to the Playmaster, as has already been mentioned the monitor output is dependent on the setting of the volume control.

As the output does not have any DC on it it could safely be connected to the line input of a computer sound card and by experimenting with the setting of the machines volume control and the level controls on the computer sound card software you should be able to make satisfactory recordings using software such as Audacity or Magix Audio lab.

Don't get too bogged down with voltage levels and such, you might want to include a series resistor of around 10k in series with the 'hot' lead between the machine and the computers sound card input, also be aware that the output from the Braemar will be mono and the input on the sound card will most likely be stereo so you will either need to parallel the left and right inputs or just record on one channel and let the software sort it out later.

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Old 23rd Aug 2019, 11:43 pm   #7
Amraduk
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

Hello Andii,

It wasn't so much that there's no DC on the monitor O/P, although that is important, provided that there are no faults that might cause that, it was more a question of signal levels and, yes, juggling the level controls on the computer and the volume control in the tape recorder had occurred to me. I will see how it goes before adding a 10K in series with the signal path.

Regards,

Dave.
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Old 24th Aug 2019, 1:58 am   #8
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

You may find that to obtain sufficient output to drive the computer the volume has to be turned up so high that the sound from the speaker is annoyingly loud. I have found this when driving an amplifier from the monitor socket on similar machines. Unfortunately it is not possible to obtain a stronger signal due to the position of the volume control in the tape recorder amplifier chain.
If this is the case then the easiest way around it is to mute the loudspeaker. To do this then you will need a long reach phono plug and a suitable resistor for the essential dummy load. These plugs are not so easy to come by now but there will be one on the supplied microphone (if available) that could be borrowed. Sometimes a direct recording lead was supplied, this should also have the necessary long plug.

Peter
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Old 25th Aug 2019, 9:10 pm   #9
Amraduk
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

Hello Peter, I thought I had replied to your post but it's not here! I have some long reach phono plugs so if I find a need to mute the loudspeaker, it will be easy to do.

Regards,

Dave.
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Old 25th Aug 2019, 9:17 pm   #10
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

Glad to hear you have the necessary plug David, not so easy to find these days. If it’s like the ones I had with 2 plastic pieces and a surrounding metal collar that has to be pushed on, I always found soldering to them was a pain!

Peter
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Old 26th Aug 2019, 9:01 am   #11
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

Quote:
Originally Posted by Amraduk View Post
The information in the R+TV service book says: "Monitor output: 400mV at 2k." With a 10K load instead, the output will of course be higher, in this case, assuming that 20V at the anode of V1b is 20V (is that about right?), it will be about 1.8V. I would think that the loading on V1a would have been taken into account at the design stage.
Sorry, missed that in your original post. Yes, then the loading should not be a problem. The 2k specified I would think is because that was a common impedence for headphones back in the day. Interesting to note that this nowadays corresponds reasonably well to the input impedence and level of a transistorized amplifier.
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Old 26th Aug 2019, 2:31 pm   #12
david freeman
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

I have connected a Playmaster to my Roksan amplifier’s line input, using the monitor output and muting the ext speaker. It sounded surprisingly good!
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Old 29th Aug 2019, 12:07 am   #13
Amraduk
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

Hello David,

That sounds promising!

Regards,

Dave.
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Old 29th Aug 2019, 12:08 am   #14
Amraduk
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Default Re: Fidelity Playmaster/Braemar Tape Recorder

Hello Peter,

No, the ones I have are metal bodied with screw-on covers.

Regards,

Dave.
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