anyone using the HM1 as a preamp into a power amp? any feedback on performance as opposed to going straight out of the HM1? eg with Abyss/Susvara.
Zähl HM1 - Reference Headphone Amplifier
- Thread starter Bkido
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Loquah
Headphoneus Supremus
Has anyone here used the HM-1's pass through RCA sockets? I have tried it now with two different amps down-chain and in both cases had significant issues with distortion that I can only assume is due to impedance issues when connecting the HM-1 plus other amps to the same output of the DAC. (Interestingly, if I use a simple RCA splitter to connect other amps it's fine - the problem only arises when the HM-1 is in the circuit using the pass-through or RCA splitters)
What have you got the HM1's gain set to and what is the output voltage from the DAC?
The HM1 has an input voltage limit of 10.6V in 0dB gain and 2V in +15dB gain.
Loquah
Headphoneus Supremus
Running TT2 in DAC mode so 2V via RCA IIRC. No issues with the DAC connected directly to the HM-1 only and not using pass through. The distortion occurs on both amps once the HM-1 is in the chain, but either amp on its own is fine (i.e. with no splitting or pass through of the cables)
Gain on the HM-1 is 0dB
Just to confirm, if you connect to the HM1, and listen through the headphone out, it's fine, but only once you connect something to the A-Thru (no other settings changed) the HM1 itself will also start to distort?
(also does the issue go away if you set the front headphone/preamp toggle to the middle setting?)
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Loquah
Headphoneus Supremus
Part 1 is correct. I'll have to check the pre-amp toggle
If it's only happening when something is connected but you're not actually changing any settings that implies some sort of severe impedance issue, is the device you're connecting to it turned on?
But also yeah make sure the preamp section is turned on. I think that has to be enabled for the A-Thru to work.
You can set it to preamp only, headphone only, or both
Loquah
Headphoneus Supremus
I removed the HM-1 entirely from my desk last night for some B-roll footage and have re-inserted it this morning with no such problems as previously. I can only assume that I had a loose interconnect or poor contact somewhere that was enough to cause problems when the input impedance reduced from having two amps connected. Same track, same amp, same headphones and no issues today.
It is a shame that the pass through doesn't work when the HM-1 is switched off though
Also, for those interested, the output toggle switch (headphones, pre-amp, both) makes no difference to the pass through.
It is a shame that the pass through doesn't work when the HM-1 is switched off though
Also, for those interested, the output toggle switch (headphones, pre-amp, both) makes no difference to the pass through.
eskamobob1
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I removed the HM-1 entirely from my desk last night for some B-roll footage and have re-inserted it this morning with no such problems as previously. I can only assume that I had a loose interconnect or poor contact somewhere that was enough to cause problems when the input impedance reduced from having two amps connected. Same track, same amp, same headphones and no issues today.
It is a shame that the pass through doesn't work when the HM-1 is switched off though
Super wierd. Glad it fixed it's self at least I guess
Loquah
Headphoneus Supremus
Yeah - definitely strange given that it happened across two different other amps connected downstream (Enleum AMP-23R and SPL Phonitor XE)
Spawn300Z
1000+ Head-Fier
Any updates on The 2023 deliveries?
RustyGates
100+ Head-Fier
What's up with the use of low quality, low reliability Jamicon caps in an 8K USD amp, instead of going with Panasonic or Nichicon at least?
When you use it as a pre-amp into a tube amp, it's magical, especially when you adjust the soundstage knob to +1. I currently use my HM1 as a pre-amp into a Nautilus. Sounds fantastic with 1266, Stealth and D8KP LE. Haven't tried Susvara yet.
Spawn300Z
1000+ Head-Fier
I was hearing that a tube as a pre to the HM-1 was magical also. Wonder which way is best.
