Balanced Input to Adcom GFP-750

[MaxBuck]

This preamplifier has a balanced input section that specifies it to be for CD player. Would this likely be acceptable for balanced DAC output also? What specification parameters would I need to research to verify this won't fry anything or lead to horrible playback sound? Right now here's all I have WRT specs:

Specifications

Output Level (Rated) 1.0V
THD + N @ Rated Output (20 Hz to 20kHz)
Balanced, <0.025%
Unbalanced, <0.095%
THD + N (1 kHz)
Balanced, <0.015%
Unbalanced, <0.017%
Output Impedance:
Balanced, <1200 ohms
Unbalanced, <600 ohms
Input Impedance:
Balanced, 94k ohms
Unbalanced, 47k ohms
Frequency Response: 20 Hz to 20 kHz, +0/-.25dB
IM Distortion (@ Rated Output):
CCIF from 4kHz to 20kHz (Balanced) <0.009%
CCIF from 4kHz to 20kHz (Unbalanced) <0.035%

SMPTE (Balanced) <0.05%
SMPTE (Unbalanced) <0.05%
Signal to Noise Ratio (Ref. To 1V)
"A" Weighted (Balanced) >102 dB
"A" Weighted (Unbalanced) >102 dB
Input Sensitivity (@ Rated Output)
Balanced 183mV
Unbalanced 365mV
Power Consumption: 30 VA

 

[Blumlein 88]

https://www.stereophile.com/solidpreamps/133/index.html

If you haven't seen this review, or maybe you have.

Older pre CD preamps sometimes had input sections that couldn't handle the more or less 2 volt input from CD players. The circuit in that preamp is very simple. It can output lots of voltage in JA's testing. His results make me think it is okay with balanced inputs of about 4 volts. You might want to keep it no higher than this from the DAC you are feeding to the balanced inputs.

 

[MaxBuck]

https://www.stereophile.com/solidpreamps/133/index.html

If you haven't seen this review, or maybe you have.

Older pre CD preamps sometimes had input sections that couldn't handle the more or less 2 volt input from CD players. The circuit in that preamp is very simple. It can output lots of voltage in JA's testing. His results make me think it is okay with balanced inputs of about 4 volts. You might want to keep it no higher than this from the DAC you are feeding to the balanced inputs.

Thanks very much!

 

[MusicNBeer]

I have this preamp and have measured this. It's super clean up to about 1Vrms input, then it hits compression and harmonics start rising fast.

I have the output voltage on my Benchmark Dac turned down to 1Vrms at full scale input.

Works great in this configuration.

 

[LTig]

https://www.stereophile.com/solidpreamps/133/index.html

If you haven't seen this review, or maybe you have.

Older pre CD preamps sometimes had input sections that couldn't handle the more or less 2 volt input from CD players. The circuit in that preamp is very simple. It can output lots of voltage in JA's testing. His results make me think it is okay with balanced inputs of about 4 volts. You might want to keep it no higher than this from the DAC you are feeding to the balanced inputs.

If I understand the review correct you can switch to passive mode if the input voltage is too high.

 

[MusicNBeer]

If I understand the review correct you can switch to passive mode if the input voltage is too high.

Yes you can. Be aware though, the input impedence in passive mode is only 2K Ohm so your source needs a good output stage to drive it cleanly.

Also, there's no balance control in passive if that matters to you.

 

[MusicNBeer]

It's unclear how the last measurement was done, the amplitude sweep. It doesn't say if it was the input voltage being raised with the volume fixed, or the input voltage fixed at 1V and the volume raised.

I assume it was input voltage raised, but it doesn't say what the volume was set to.

Regardless, it's not an overly useful device anymore with DACs providing such clean variable volume by remote. It does have silky smooth controls and looks cool to me.