HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

Hi,

1. What is the volume control? Pot or SA?
2. How critical is 60cm spacing between PSU and Amp?
3. Is XLR an input option?
4. Is Balanced an output option?

Thanks.

Well, look who's back in town !




You'll need Savvy or Tomasz to reply on that headphone amp.

Hi, George,

1. Alps Blue Velvet pot fitted as standard. Stepped attenuator option add £425 - same as in the P50SA: https://nvahifi.co.uk/products/nva-p50s ... eamplifier

2. The + version has 2 x 120va transformers in a second case. 60cm will ensure there is no EMF interference - in most instances, 30 to 40 cm will be fine, but you definitely won't be able to sit one on top of the other.

3. No. For two reasons. First, space is already limited. Second, there is no benefit to balanced connection in a domestic set up. It's only beneficial if you are running interconnects that are over 10 metres. It has become fashion among manufacturers (and consumers) who want to appear to be 'pro'. In a pro setting it is used to avoid noise with very long cable runs (sometimes in excess of 50 metres). If you hear a difference with normal length cables, it will be for one of a few reasons - the balanced output from the source has a slightly higher voltage output than the single ended output, or the single ended output stage has been deliberately downgraded.

4. No. There is no benefit with the NVA circuit. In some headphones amps, a balanced output is used to increase power. The AP10H is essentially a speaker amp fed through a headphone output - it has all the power, and more, that you will ever need.

Hope this helps. Tomasz can talk you through it, at length, if you want to have a deeper understanding.

PS. If you want to use the balanced output from your pre-amp / dac to the AP10H, you can do so using the appropriate convertor.

Thank you.

They'd be in separate shelves on my headphone station rack; between 30 and 40cm apart.

I shall have a little think to myself and get back to you.

Out of curiosity, are there any AP10H+ owners on the forums I can speak to?

We've sold 2 AP10H+ sets but neither owner is on the forum.

Did you see the Hi-Fi World review of the standard AP10H?

If not, here's the link: https://cdn.shopify.com/s/files/1/0104/ ... 1605018485

The AP10H+ is, effectively, the same as the Jammy Special that Doc made for him - just that the 2 x 120va power supply is now all in one case and the ALPS volume pot is a bit of an upgrade on what Doc used to fit.

Thanks for the link, I hadn't seen that. A nice review.

In the little grey box on the 3rd page the reviewer raised an issue of 'unusually high output impedance' but didn't suggest what the cause or impact may be. Can you explain?

Were I to order, what would the lead time be?

Thanks.

George Hincapie wrote: ↑Fri Jan 15, 2021 1:50 am Thanks for the link, I hadn't seen that. A nice review.

In the little grey box on the 3rd page the reviewer raised an issue of 'unusually high output impedance' but didn't suggest what the cause or impact may be. Can you explain?

Were I to order, what would the lead time be?

Thanks.

Remember the starting point – the AP10P is a speaker amplifier, the AP10H is a speaker amplifier that is 're-routed' through a headphone output with a padding resistor inserted to give appropriate volume levels. Adding the resistor creates output impedance – without it the amp would be too powerful and you would only be able to turn the volume control a tiny amount without damaging your ears. Re-routing the speaker output via a resistor is also how it used to be done by the Japanese in their 1970s amps / receivers, which are highly prized, today, by users of 'difficult' headphones as an affordable (and cool) way of getting the power they need. With modern stand alone headphone amps, though, there is much less power, so they are looking to keep impedance low in order to retain sufficient voltage – NVA is using impedance to reduce power, to avoid damaging you or your headphones! The NVA implementation is no longer the norm, but is becoming popular again among users with very high impedance headphones or planar magnetic headphones, which are known to be hard to drive.

Here's the update on production times: viewtopic.php?f=32&p=215814#p215814

George Hincapie wrote: ↑Fri Jan 15, 2021 1:50 am Were I to order, what would the lead time be?

Thanks.

PS. The standard AP10H is in stock - can be with you next week. It is more than enough for 95% of users. If you have 'very difficult' headphones, though, then the + version will give you extra headroom (no pun intended). Which headphones are you using, George?

I am currently using the AudioQuest Night Hawk Carbon headphones. I am also thinking about buying these: https://www.linsoul.com/products/harmonicdyne-zeus

Will PM you.

George Hincapie wrote: ↑Fri Jan 15, 2021 11:42 am I am currently using the AudioQuest Night Hawk Carbon headphones. I am also thinking about buying these: https://www.linsoul.com/products/harmonicdyne-zeus

Will PM you.

PM replied