[Fafner]

Yesterday I had a listen at Philip Glass's "Itaipu" recording with the Atlanta forces. This isn't exactly the most clear recording around, still I always like it to test audio equipment, given its extreme dynamic range.
Well, the Zähl was able to extract details which always eluded me with my previous amps, both in the very subtlest pianissimo and in the loudest passages, where lesser stuff just give you a wall of sound without much focus into how it's built. It was like looking at the score through a magnifying glass.

 

[GoldenSound]

Come on. You use a DAC with an external clock.

Plenty of us have been using after market headphone cables, fuses, power cables, etc etc I've got both chassis of my HM1 connected to a Shunyata Altaira grounding system. Everything is fair game, and there is indeed improvement to be had over stock.

External clocks can demonstrably provide a measurable improvement though. (Actual word clocks at least, which is how dCS does it. External 10Mhz clocks are a different matter)

 

[IanB52]

External clocks can demonstrably provide a measurable improvement though. (Actual word clocks at least, which is how dCS does it. External 10Mhz clocks are a different matter)

Depends on how you define improvement, and improvement over what.

I concede that they do sound good in a lot of applications, but if you are going from the data purist perspective, external clocks just add flavored jitter. The consensus in the audio engineering world is that an external clock can only add jitter unless the internal one is particularly bad.

I have no problem with them, as I have no problem with after market DC cables, fuses etc.

Most hifi DAC manufacturers subscribe to this as well with the exception of DCS, Esoteric, and a few others.

 

[Fafner]

Looks like my HM1 will need a repair already.
Suddendly, I'm not getting sound from the A input anymore! Tried to use input B with my Bartok fearing that it was the culprit, but it's working fine there.
Another sign something is wrong is that on input A I'm not getting the relay click when putting the volume to 0 or getting out of it (getting it on input B, and was getting it on A as well until today).

 

[GoldenSound]

Looks like my HM1 will need a repair already.
Suddendly, I'm not getting sound from the A input anymore! Tried to use input B with my Bartok fearing that it was the culprit, but it's working fine there.
Another sign something is wrong is that on input A I'm not getting the relay click when putting the volume to 0 or getting out of it (getting it on input B, and was getting it on A as well until today).

This occurred on one other unit. Turns out a jolt during shipping had caused one of the logic circuit connectors to come loose. So no actual damage/easy fix but still annoying that it happened.

Zahl should be able to fix you up quick (or with their guidance you may even be able to just open the amp and reconnect it yourself but check with zahl before doing this of course)

 

[Fafner]

It would be great if this could be fixable without sending it. Let’s see what Zähl replies me.

 

[Frankie D]

It would be great if this could be fixable without sending it. Let’s see what Zähl replies me.

Very curious to hear how this is handled ( as I have one on order ). Please keep us posted.

 

[Roasty]

hey guys
just realized my HM1 power supply/mains adaptor box emits a really faint but audible hum/buzz when the HM1 is powered on. it comes from the mains adaptor box and not the HM1 unit. it doesn't transmit thru to headphones. it goes away when the HM1 is turned off.

does yours do that too? I never heard it until now; it's 4.30am in a super quiet room. my HM1 had been in the lounge previously where there was a bit more background noise.

not sure if u guys can view the vid but here is the link https://drive.google.com/file/d/1WmmNLqv4XFtOcPzA2igUF4NCtIyvQZ5R/view?usp=drivesdk

 

[GoldenSound]

hey guys
just realized my HM1 power supply/mains adaptor box emits a really faint but audible hum/buzz when the HM1 is powered on. it comes from the mains adaptor box and not the HM1 unit. it doesn't transmit thru to headphones. it goes away when the HM1 is turned off.

does yours do that too? I never heard it until now; it's 4.30am in a super quiet room. my HM1 had been in the lounge previously where there was a bit more background noise.

not sure if u guys can view the vid but here is the link https://drive.google.com/file/d/1WmmNLqv4XFtOcPzA2igUF4NCtIyvQZ5R/view?usp=drivesdk

This is normal with any transformer in the presence of high mains THD (or DC offset, but 9/10 times it's just high THD).
The transformer core gets saturated and causes an audible vibration.

It doesn't cause any degredation in performance and isn't anything to worry about, just means that the power efficiency may be a hair lower. Amplifier performance/behaviour will be unaffected

To fix it you'd need to use a power regenerator. Can also try a DC blocker but given as the issue is usually high THD this normally won't fix it.

Depending on where you live, High mains THD may simply be a permanent issue. Other times it's a temporary thing and you should check if its only occurring if you have a large reactive load like a washing machine or refrigerator compressor running.

 

[jlbrach]

hey guys
just realized my HM1 power supply/mains adaptor box emits a really faint but audible hum/buzz when the HM1 is powered on. it comes from the mains adaptor box and not the HM1 unit. it doesn't transmit thru to headphones. it goes away when the HM1 is turned off.

does yours do that too? I never heard it until now; it's 4.30am in a super quiet room. my HM1 had been in the lounge previously where there was a bit more background noise.

not sure if u guys can view the vid but here is the link https://drive.google.com/file/d/1WmmNLqv4XFtOcPzA2igUF4NCtIyvQZ5R/view?usp=drivesdk

sadly this is a recurrent problem with power amps..especially tube amps...if it isnt too bothersome and doenst come through the headphone best to ignore it if possible

 

[Roasty]

This is normal with any transformer in the presence of high mains THD (or DC offset, but 9/10 times it's just high THD).
The transformer core gets saturated and causes an audible vibration.

It doesn't cause any degredation in performance and isn't anything to worry about, just means that the power efficiency may be a hair lower. Amplifier performance/behaviour will be unaffected

To fix it you'd need to use a power regenerator. Can also try a DC blocker but given as the issue is usually high THD this normally won't fix it.

Depending on where you live, High mains THD may simply be a permanent issue. Other times it's a temporary thing and you should check if its only occurring if you have a large reactive load like a washing machine or refrigerator compressor running.

Thanks for the info! that was reassuring.

I have some pics from my power conditioner which tbh I don't know how to interpret, but fwiw..

I notice the value on the power conditioner reads 244v. I have my Zähl unit set at 230v. should I change it up to 240v or just leave as is? or doesn't make a diff?

 

[GoldenSound]

I notice the value on the power conditioner reads 244v. I have my Zähl unit set at 230v. should I change it up to 240v or just leave as is? or doesn't make a diff?

Yeah I'd set it to 240V (turn the unit off first ofc)

 

[RobertSM]

This occurred on one other unit. Turns out a jolt during shipping had caused one of the logic circuit connectors to come loose. So no actual damage/easy fix but still annoying that it happened.

Zahl should be able to fix you up quick (or with their guidance you may even be able to just open the amp and reconnect it yourself but check with zahl before doing this of course)

Sorry chap. You're not qualified to make an armchair diagnosis on this.

Maybe this is similar to an issue you've heard about? Could be. But your achilles heel is clearly your inexperience and lack of internal self control.

 

[chesebert]

It is difficult to get a man to understand something, when his salary depends on his not understanding it.

 

[Frankie D]

?????