nOhr ACA 2b....how quiet is it?

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acresm22

nOhr ACA 2b....how quiet is it?
« on: 16 Feb 2007, 07:34 pm »
Hello all,
I'm seriously considering the ACA 2b pre, and was hoping some of you owners out there could comment on how quiet it is. I have an ASL 300B amp driving Klipsch LaScalas. The LaScalas, at 104 db 1st/1mt, are ruthlessly revealing of upstream noise. The ASL is a very quiet SET amp, so I want to make sure the pre adds as little (or no) noise as possible. I'm using a tube pre now that was described an another forum as "dead quiet," but I can easily hear hum from my listening position with the volume only a quarter open.

So....for you ACA owners out there, if you turn the volume up wide open with no music playing, can you hear hum in addition to the normal tube hiss?

Any other comments on sonic quality would be much appreciated. Thanks!

Dan

steve k

Re: nOhr ACA 2b....how quiet is it?
« Reply #1 on: 16 Feb 2007, 07:39 pm »
When I had mine, it was very quiet--until I rolled other tubes into it. In my system, this preamp would only work with the stock EH tubes. I tried 8-10 other brands of 6922/7308 and 6DJ8 and they all went microphonic in it. So unless you're willing to use only the stock tubes, I wouldn't recommend it.
steve

guest1632

  • Guest
Re: nOhr ACA 2b....how quiet is it?
« Reply #2 on: 18 Jul 2007, 10:51 am »
Hello all,
I'm seriously considering the ACA 2b pre, and was hoping some of you owners out there could comment on how quiet it is. I have an ASL 300B amp driving Klipsch LaScalas. The LaScalas, at 104 db 1st/1mt, are ruthlessly revealing of upstream noise. The ASL is a very quiet SET amp, so I want to make sure the pre adds as little (or no) noise as possible. I'm using a tube pre now that was described an another forum as "dead quiet," but I can easily hear hum from my listening position with the volume only a quarter open.

So....for you ACA owners out there, if you turn the volume up wide open with no music playing, can you hear hum in addition to the normal tube hiss?

Any other comments on sonic quality would be much appreciated. Thanks!

Dan

Hi Dan,

I'm just now looking at this forum, and seeing your question. I realize this is about almost 6 months later, and well ...

I was considering getting the 2B. I asked Mike what the noise figure was, and he told me it was about 93DB. I don't know if that is weighted or not. I too would like some more info on the 2b. How good is it versussome other tube prees out there?

Ray

Cazza

  • Jr. Member
  • Posts: 21
Re: nOhr ACA 2b....how quiet is it?
« Reply #3 on: 8 Aug 2007, 10:23 pm »
I have been running the 2B for about 2.5 years now. It took me some time to find a good set of tubes , did not like the Sovteks(dull), JJ/Tesla were better but a bit noisy and I have eventually settled on the Philips NOS 6dJ8 tubes (tried a few pairs, until I settled on a pair). These are pretty good - excellent soundstage and detail. My 2B has been really quiet from the start - there is a little hum but it is not noticible from 1m from my speakers. I know the hum is from the 2B because you can mute the output. In my situation I have had more issues with the LII. I have 2 from the from first batch. The one amp blew up and I got a local guy to rebuild them - the assembly was shocking with a massive board bend in the SPS(talking 3 mm at least). So the board mountings were modified, grounding issues re-solved and SPS was fixed. At the time I was a little annoyed. Since then perfect. The hum from both LII and 2B is so low that I don't hear it at all when playing music - even classical or soft background music.

I must be one  few :D Norh customers around. Both the 2B and LII are excellent audio products. The depth, bass and clarity are superb

 

guest1632

  • Guest
Re: nOhr ACA 2b....how quiet is it?
« Reply #4 on: 8 Aug 2007, 10:44 pm »
I have been running the 2B for about 2.5 years now. It took me some time to find a good set of tubes , did not like the Sovteks(dull), JJ/Tesla were better but a bit noisy and I have eventually settled on the Philips NOS 6dJ8 tubes (tried a few pairs, until I settled on a pair). These are pretty good - excellent soundstage and detail. My 2B has been really quiet from the start - there is a little hum but it is not noticible from 1m from my speakers. I know the hum is from the 2B because you can mute the output. In my situation I have had more issues with the LII. I have 2 from the from first batch. The one amp blew up and I got a local guy to rebuild them - the assembly was shocking with a massive board bend in the SPS(talking 3 mm at least). So the board mountings were modified, grounding issues re-solved and SPS was fixed. At the time I was a little annoyed. Since then perfect. The hum from both LII and 2B is so low that I don't hear it at all when playing music - even classical or soft background music.

I must be one  few :D Norh customers around. Both the 2B and LII are excellent audio products. The depth, bass and clarity are superb

 

Hi Cazza,

I had heard there was lots of problems with the Le Amp II. Sincthen, the Le amp III with the lower wattage, and hopefully more stable mechanics is better.

So where did you end up getting the NOS 6j8 at? I've been told that you might be able to substitute a 6n1p to the mix. I'm trying to get this confirmed.

Ray

Cazza

  • Jr. Member
  • Posts: 21
Re: nOhr ACA 2b....how quiet is it?
« Reply #5 on: 9 Aug 2007, 07:37 am »
Hi Ray

I live down under (OZ) and eventually went to a local dealer specializing in tubes. Like Steve indicated, not every tube works with the 2b. I even tired a set of matched Telsa military NOS tubes (bloody expensive) - totally unuseable, the feedback was bad. The dealer I worked with provided me the philips tubes. These are very quiet and work well with the 2b.

guest1632

  • Guest
Re: nOhr ACA 2b....how quiet is it?
« Reply #6 on: 9 Aug 2007, 11:23 am »
Hi Ray

I live down under (OZ) and eventually went to a local dealer specializing in tubes. Like Steve indicated, not every tube works with the 2b. I even tired a set of matched Telsa military NOS tubes (bloody expensive) - totally unuseable, the feedback was bad. The dealer I worked with provided me the philips tubes. These are very quiet and work well with the 2b.

Hi Cazza,

So then you just got a pair of Philips 6j8 tubes, and that worked. I just don't want to end up going through what you went through. Were they the military type too, or just the normal Philips 6J8's? Any info you can give me would help. Thanks. I'm sorry but I don't know to much about the tube stuff yet. It just seemed like a good preamp for starters.

Ray

Cazza

  • Jr. Member
  • Posts: 21
Re: nOhr ACA 2b....how quiet is it?
« Reply #7 on: 9 Aug 2007, 09:24 pm »
Hi Ray

I purchased the standard Philips NOS version.

Regards Anthony

guest1632

  • Guest
Re: nOhr ACA 2b....how quiet is it?
« Reply #8 on: 10 Aug 2007, 12:21 am »
Hi Ray

I purchased the standard Philips NOS version.

Regards Anthony

Hi Anthony,

Ok, sounds good.

Ray