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500B TAPE HEAD/TAPE MON Input Questions

Rockyhill

Rockyhill

AK Subscriber
Subscriber
The 500B has TAPE MON & TAPE HEAD input jacks. Are these inputs of equivalent sensitivity, more or less?

I use AUX and TAPE MON; TAPE MON is significantly less sensitive. As a result I only use it with a DAC that has adjustable output to overcome that reduced sensitivity (specs for the Grant TubeDAC-11 Output Level: DAC output: 2V, pre line output/ tube buffer output:max 6V.) I use the pre line out and have the control set at about "2 o'clock". Not sure what voltage is being delivered.

Would I be better off using the fixed 2V DAC output to avoid damaging the receiver?

https://www.hifiengine.com/manual_library/fisher/500-b.shtml

I recall, but can't locate, a thread that discusses how to change one of the tape inputs into a line level input. If it's not too complicated I might consider that. I have recently obtained an external RCA input selector switch so this is less of a need, however, but as the system evolves one never knows what new input devices one will need to connect!.
 
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Tape Mon and TAPE HEAD are NOT Equivalent in sensitivity. Actually the TAPE HEAD is analogous to Phono for a Mag cartridge with a slightly different Equalization called NAB. It's only for use by TAPE DECKS that DO NOT have a preamp on them like a TEAC A4000 or other decks with no amplifier electronics. The Tape Heads are wired direct to the RCA's on the back of the deck and connect to the TAPE HEAD input. It then gets amplified and equalized in the 500b. Tape Monitor is more of a line level(even tho right now it's slightly less in sensitivity than the AUX on the 500B due to it being closer to the final output section by 1 preamp gain circuit.

You'd overload the receiver using the 2V fixed on the DAC to Aux or Tape Mon.. I'd use the adjustable and keep it under 250mv. See the spec's for the 500b below.

ScreenHunter_31 Jan. 02 13.43.jpg
 
larryderouin said:
Tape Mon and TAPE HEAD are NOT Equivalent in sensitivity. Actually the TAPE HEAD is analogous to Phono for a Mag cartridge with a slightly different Equalization called NAB. It's only for use by TAPE DECKS that DO NOT have a preamp on them like a TEAC A4000 or other decks with no amplifier electronics. The Tape Heads are wired direct to the RCA's on the back of the deck and connect to the TAPE HEAD input. It then gets amplified and equalized in the 500b. Tape Monitor is more of a line level(even tho right now it's slightly less in sensitivity than the AUX on the 500B due to it being closer to the final output section by 1 preamp gain circuit.

You'd overload the receiver using the 2V fixed on the DAC to Aux or Tape Mon.. I'd use the adjustable and keep it under 250mv. See the spec's for the 500b below.

View attachment 844949
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Thank you sir.
 
Resurrecting this old thread. I’m reconfiguring my setup and want to connect a miniDSP 2x4 HD to the Fisher AUX. What off the shelf product can I use to drop the 2v output to a safe level?
 
Yep,
Here are examples:

266-240_HR_0.jpg


Parts Express has 3dB, 6dB, and 12dB (no affiliation).
 
Let's run the numbers:

dB (voltage) = log (v2/v1)x20 = log (.25/2.0) x 20 = -18 dB.

So, none of them attenuates that much. The 12 dB would get you to 500 mV. The 500B can easily handle 500 mV through the AUX input.
 
Well, looked at that spec sheet and I suppose 500mV is a bit high (I take there is no output level control on your device). You could daisy-chain the 6 and the 12 dB units for 18 dB total attenuation, I guess (dB are additive).
 
Got the attenuators today. -24 dB. It’s been a long time since I played with functions so I don’t know the voltage drop but a CCA connected to the aux input sounds great.
 
I now have -18dB attenuation going into AUX. (-6 + -12). I’m finding the volume control needs to be set to 11+ (haha) in order to get reasonable output. Does that sound right? I’m tempted to remove the -6 attenuators.
 
Give it a try--may be the best set up for your unit.

To answer your question, I'm usually comfortable if robust listening volume (i.e. the 'first watt' of output) happens around 10 to 11 o'clock on the dial. This eliminates minor volume control tracking issues that can happen if you have to have the control scrooched all the way down before things start getting loud.

I'm not looking for 'Spinal Tap' levels at this position, just room filling sound where I can hear the details.
 
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He's crazy, white haired, glows at night.........And drives a DeLorean. ;)
 
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Consider that 2v number is likely peak output. It won't be that high all the time unless you listen to music that was mastered at "11" with lots of compression.

also tend to agree that a less-touchy volume control is a good thing. So many things do all the useful work below 10:00
 
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