[adanac061]

Just thought id pass this along, pretty interesting thread.
People with more technical knowledge might understand the arguing more than me...

Its a thread about NVa amps and equipment , the actual owner and creator
richard dunn jumps onboard and it goes down hill from there ..Enjoy

http://www.zerogain.com/forum/archiv...p/t-13158.html

Full version

http://www.zerogain.com/forum/showthread.php?t=13158

 

[Richard Dunn]

Quote:

Originally Posted by adanac061 /img/forum/go_quote.gif Just thought id pass this along, pretty interesting thread. People with more technical knowledge might understand the arguing more than me... Its a thread about NVa amps and equipment , the actual owner and creator richard dunn jumps onboard and it goes down hill from there ..Enjoy http://www.zerogain.com/forum/archiv...p/t-13158.html Full version http://www.zerogain.com/forum/showthread.php?t=13158

They are a funny lot at zerogain and the moderators are the nastiest of the lot. They even have a private forum called "guards chat" just for the moderators so they can be rude about and take the piss out of the members behind their backs. They put me on by accident and I had an amusing 6 months reading it, when I thought I ought to tell them of their mistake. So they booted me off the whole forum in case I told anyone

Richard

 

[elnero]

Are you the Richard Dunn of NVA?

 

[Richard Dunn]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif Are you the Richard Dunn of NVA?

No he is just a figment of my imagination, he never really existed.

Richard

 

[elnero]

Quote:

Originally Posted by Richard Dunn /img/forum/go_quote.gif No he is just a figment of my imagination, he never really existed. Richard

lol

Nice to see you here!

I'm hoping to get to hear adanac061's AP10H at the meet we're having here on PEI in a couple of weeks. I tried one briefly with a pair of Audio Technica W100's a few years back, I quite liked the sound but I did notice some noise. The AT's are only about 30 or 32 ohms and your recommendations for the amp was a headphone impedance minimum of around 200 to 300 ohm. With that in my mind I veered away from buying one but I'm curious if the low impedance would be responsible for the noise and what detrimental effects there would be using lower impedance headphones with the amp?

 

[Richard Dunn]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif lol Nice to see you here! I'm hoping to get to hear adanac061's AP10H at the meet we're having here on PEI in a couple of weeks. I tried one briefly with a pair of Audio Technica W100's a few years back, I quite liked the sound but I did notice some noise. The AT's are only about 30 or 32 ohms and your recommendations for the amp was a headphone impedance minimum of around 200 to 300 ohm. With that in my mind I veered away from buying one but I'm curious if the low impedance would be responsible for the noise and what detrimental effects there would be using lower impedance headphones with the amp?

I posted this to the other nva thread :-

*The website is out of date about the AP10h. The one produced up to 2000 was the same circuit as the other AP10 series amps, but output transistors removed as the driver transistors had more than enough guts (current drive), even just about enough for the Grados. The new incarnation leaves in the output transistors and feeds the phones via large wirewound resistors which we change according to the headphones being used so it will drive 1ohm phones if need be. I did the change because I now use Grados.

All the NVA integrated and stereo power amps now have the option of this same circuit built in.*

What sort of noise?

Richard

 

[elnero]

It was just a low level background noise, nothing too serious but could have had the potential to be annoying on softer songs. I had always assumed it was the impedance mismatch but possibly it was just an anomoly displayed by that one particular amp.

One other thing I forget, can the headphone amp also be used as a speaker amp?

 

[Richard Dunn]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif It was just a low level background noise, nothing too serious but could have had the potential to be annoying on softer songs. I had always assumed it was the impedance mismatch but possibly it was just an anomoly displayed by that one particular amp. One other thing I forget, can the headphone amp also be used as a speaker amp?

That is AP10p for one input or AP10x for four inputs and selector switch. AP10x you have to go for the headphone option as well. All 10 series are the same circuit but AP10h has smaller PSU and no heatsinks on the output devices, they just sink heat to the base.

Go to ebay for full listings.

Noise - hum or hiss?

How old was the unit. Pre 2000 or since 2006, there was a 6 year gap in production. The new ones are better.

Richard

PS regarding current delivery question that I note from another thread, it has 4 12amp darlingtons - potential at max device design voltage swing of 48amps, talk about overkill, it could explode your brain cavity (lol). Luckily restricted by series wirewound resistors, much lower voltage swing and power supply VA. But it will drive anything down to a bit of wet string hanging off your ears, I just wouldn't recommend wet string for music.

 

[elnero]

This was an older one, as I said it was a few years back now and only a brief listen at the dealer/distributor in Nova Scotia. If I remember correctly it was more of a hiss than a hum because I didn't characterize it as a possible grounding issue.

A good friend of mine owns one which I had heard with HD600's previous to the audition I'm referring to, this was a mesmorizing experience and probably one of the defining moments that turned me towards realizing headphones could serve as a true hi-fidelity listening experience.

 

[Richard Dunn]

Quote:

Originally Posted by elnero /img/forum/go_quote.gif This was an older one, as I said it was a few years back now and only a brief listen at the dealer/distributor in Nova Scotia. If I remember correctly it was more of a hiss than a hum because I didn't characterize it as a possible grounding issue. A good friend of mine owns one which I had heard with HD600's previous to the audition I'm referring to, this was a mesmorizing experience and probably one of the defining moments that turned me towards realizing headphones could serve as a true hi-fidelity listening experience.

Probably a source problem, the amp is completely silent.

As I said the same result can now be obtained by fitting the circuit to any of the integrated series amps AP's 10 20 30 50 70 80 and either of the stereo power amps A30 and A60 (obviously monos power amps would be difficult requiring wiring your headphones to two seperate mono jacks). We are keeping the price very low for this mod at £20. The AP10H (obviously) and AP10P are fitted as standard.

Richard

 

[elnero]

Very interesting, I'm more intrigued than ever to hear one again. I sure hope adanac061 makes it to the meet at the end of the month.

It's really interesting to hear that you're now able to fit the circuit to most of your amps, IMO decent, reasonably priced integrateds with good headphone circuits is something that's many Head-Fiers have been looking for but to date have been very hard to come by. Myself, I had wanted to replace my old Mission Cyrus I with one of the NVA's back when I first heard my friends AP10, this news makes that an appealing prospect again .

Thanks for taking the time to talk Richard.

 

[Jammy]

Hi Richard.
Fancy meeting you here.....ha.
Lovin my AP10h JS have posted a few pics here, but mods have got to check em out first apparently cause im new here.
Different thread....
Jammy.