Just picked up my REF40 today.... Wow!

Originally Posted by joeinid

Any update on how your Ref. 40th's are sounding? Curious minds ....

+1

[uncle_dito]

Hello all, this is my first post in the forum

I just bought a second hand Audio Research Ref 3. Quite happy except one issue. I can hear hiss (like "shhhhhhh") through the speakers coming from the Pre, from my listening position, which is about 8-9 feet away from the speakers! I know it is normal to hear some hiss if you put your head close to the speakers, but not at this distance. The hiss is coming from both channels, and can be heard from volume setting 1. The loudness of the hiss doesn´t increase with volume, and is independent of the sources, even with no source connected, there it is. It is loud enough to bother me in quiet music passages or when I play soflty at night.

I have done a few tests:

1. try different interconnects. Try balanced or single ended source inputs. Still the same noise from both channels.
2. try different amplifiers. Then I discovered that the noise was coming only when using the Pre Main RCA or single ended Line outs (1 or 2). With the Balanced outputs, the pre was dead silent (ok, except some erratic noise, like "frying", coming from one of the channels, but not the problematic hiss described. I assume this other sporadic noise is from one or a couple of 6H30 going wrong out of the 4). The valves have about 800hrs. As I have a singled ended amplifier (Musical Fidelity A5 CR power amp), I need to get this issue sorted.
3. Try a different 6550C. Still the hiss.
4. Try rotating the 4x 6H30, the noise was still coming from both channels, it did not go to the left or right).

Ok, so what do you think? Before I send it to the official service in another city, I wonder what the issue might be and if I should try something else. I am tempted to buy and replace all valves, but I wonder if the problem might be something else.

Thanks for your comments.

[Dafos]

A somewhat similar problem occured with my ref cd 7 player where hiss only manifested itself when using the single ended outputs. The problem was a a bad 6h30 regulator tube that in turn damaged some diodes or capacitors, can't quite recall exactly. You may want to try replacing the 6h30 regulator tube which is located next to the 6550 regulator tube. If the problem persists, I suggest you have the unit inspected by an authorized audio research representative. I'm pretty sure it's not a serious problem and can be diagnosed and repaired quickly.

[BillK]

While that sounds like more hiss than usual, it's one of the reasons I wasn't happy with the LS-17 I demoed as I could clearly hear the hiss from my usual listening position.

[Dafos]

Audible hiss from the listening position EVEN with the volume turned up to around 60 is not normal for the newer generation of ARC line stages if no source component, particularly high gain phono stages, is not connected to it.

[jwhite613]

uncle_dito... Welcome To AA!!!

[PHC1]

Originally Posted by uncle_dito

Then I discovered that the noise was coming only when using the Pre Main RCA or single ended Line outs (1 or 2). With the Balanced outputs, the pre was dead silent (ok, except some erratic noise, like "frying", coming from one of the channels, but not the problematic hiss described.

Sounds like you are halfway to solving your problem... Try routing your RCA cables differently and/or a different set of RCA ICs.

[joeinid]

Originally Posted by jwhite613

uncle_dito... Welcome To AA!!!

+1

Hi!

[TMcD]

Originally Posted by Dafos

Audible hiss from the listening position EVEN with the volume turned up to around 60 is not normal for the newer generation of ARC line stages if no source component, particularly high gain phono stages, is not connected to it.

I agree. I hear zero hiss at high volumes on my Ref 5. S

[SRT-10 Viper]

Originally Posted by joeinid

Any update on how your Ref. 40th's are sounding? Curious minds ....

I have 650 hours on it and and the sound has really improved from the early hours. The sound stage is wide and deep. Instruments sound like they are in the room... If you close your eyes you hear/feel where each one is in the room. Cymbals, pianos, classical guitars, trumpets... All sound like the actual instruments to my ears. I've had the REF3, REF5 and now the REF40. The REF3 was a huge jump for me from a Mark Levinson 320. The REF5 was a nice move up from the REF3 more of evolutionary upgrade. The move from the REF5 to the REF40 is bigger to me then when I moved to the REF3. It is really that good.