Minimizing Tube Rush / Hissing

[shadowlight]

Hello,

With GR-Research V2 being 92db sensitive I am hearing a lot of tube rush / hissing.  How do I go about reducing that?

Thanks

[richidoo]

Hiss/rush is probably old or defective tubes. What amp is it?

92 is not so sensitive that noise should be a problem as long as the amp is healthy. All tube amps make some noise tho... hiss is usually easily ignored. But rushing means something wrong.

[shadowlight]

Hiss/rush is probably old or defective tubes. What amp is it?

92 is not so sensitive that noise should be a problem as long as the amp is healthy. But all tube amps make noise, you just have to get over it, focus on the magic - if the amp is good it's worth some noise.

The amp is Vincent SP331 (but had hiss/tube rush couple of other amps also) with Response Audio Bella LP Tube Pre.  Will swap the tubes to see if the hiss is reduced.

[richidoo]

Deepak you caught me editing!     You are fast!!

Try removing the preamp if you have a source with a volume control, even ipod or something will be quiet for the test.  I'll check out the Vincent specs.

[richidoo]

The Vincent is a hybrid, with tube input stage. It uses extremely quiet and reliable modern tubes from the 80s. They are so reliable that they are soldered onto the PCB, and will last the life of the amp. So I doubt the noise is coming from the amp. If you have a way to short the input jack, then you can safely run the power amp with no source component, then you will be hearing only the amp, which would verify whether it is the problem.

The all tube preamp (using vintage 6sn7 or 12au7s?) is much more likely the culprit. Easy fix, buy some Sovtek/EH preamp tubes to use for testing and as a backup set. They might not sound as delicious as vintage tubes, but they are reliable and quiet. Cheap too, and probably available at your local music store.

[Triode Pete]

My 104 dB sensitive horns are dead silent at idle with my all tube gear, including my CD player... my tubes date from the 1930's (Sylvania 2A3), 1940's (Tung Sol Round Plate 6SL7), 1950's (WE 417A) & 1960's (Mullard 5AR4, Siemens 6DJ8, Tung Sol 5687, etc.)... age has nothing to do with noisy tubes as long as they have no shorts and suitable mutual conductance (u-mhos)...

Check & clean your interconnects with a good contact cleaner like Caig DeOxit Gold. Also, check & see (actually hear) if your IC's are shielded. Some components really need shielded IC's. You may be picking up a 60 Hz hum from some power supply transformers or other electrical anomalies... perhaps a ground loop as well!

Finally, use a quiet power cord... yes, I have heard "noisy" power cords!

My $0.02 to help... Happy Thanksgiving --- Pete

[richidoo]

age has nothing to do with noisy tubes

Agreed. I meant worn out.

[shadowlight]

Deepak you caught me editing!     You are fast!!

Try removing the preamp if you have a source with a volume control, even ipod or something will be quiet for the test.  I'll check out the Vincent specs.

I will hook up the Logitech Touch directly to the amp.  I am pretty sure the hiss/rush is from the preamp.  I have a stack of various tubes to try.

Check & clean your interconnects with a good contact cleaner like Caig DeOxit Gold. Also, check & see (actually hear) if your IC's are shielded. Some components really need shielded IC's. You may be picking up a 60 Hz hum from some power supply transformers or other electrical anomalies... perhaps a ground loop as well!

Thanks Pete.  Will try your suggestions.  Where would I find the deoxit stuff?

[richidoo]

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=341-200

Saw this cool little RCA cleaning tool the other day:
http://www.musicdirect.com/p-9658-signet-rca-cleaning-tool-ea.aspx

[Triode Pete]

Deepak you caught me editing!    You are fast!!

Try removing the preamp if you have a source with a volume control, even ipod or something will be quiet for the test.  I'll check out the Vincent specs.

I will hook up the Logitech Touch directly to the amp.  I am pretty sure the hiss/rush is from the preamp.  I have a stack of various tubes to try.

Check & clean your interconnects with a good contact cleaner like Caig DeOxit Gold. Also, check & see (actually hear) if your IC's are shielded. Some components really need shielded IC's. You may be picking up a 60 Hz hum from some power supply transformers or other electrical anomalies... perhaps a ground loop as well!

Thanks Pete.  Will try your suggestions.  Where would I find the deoxit stuff?

I prefer the "Gold Version" of deoxit... free shipping / no tax with Sweetwater...http://www.sweetwater.com/store/manufacturer/CAIG_Laboratories

[Response Audio]

Hello Deepak,
As mentioned, I would certainly try some different tubes. NOS 12AU7's can often be noisy. The circuit should be dead quiet. I ran that preamp with some very efficient speakers (above 95dB) when it came back to me for the changes and it would not have gone out the door if it was noisy.

Please keep us posted of your results. If you continue to get noise with different tubes, let me know again via email or give me a call and we can walk through it.

Have a Happy Thanksgiving.

[shadowlight]

Hello Deepak,
As mentioned, I would certainly try some different tubes. NOS 12AU7's can often be noisy. The circuit should be dead quiet. I ran that preamp with some very efficient speakers (above 95dB) when it came back to me for the changes and it would not have gone out the door if it was noisy.

Please keep us posted of your results. If you continue to get noise with different tubes, let me know again via email or give me a call and we can walk through it.

Have a Happy Thanksgiving.

Thanks Bill.  If I continue to have the issue will reach out to you.

Happy Thanksgiving.

[etcarroll]

D -

All the tubes I ran through my Purity were dead quiet, except my present faves, the ribbed plate Teles. Minor tube rush, which is excaberratted by the Reference 3s. When I had your LS6s it wasn't as noticeable, nor is it with the Vandys which I have playing Chet Baker right now, a 'quietish' album that would allow tube rush to present itself with the Ref 3s.

Try other tubes is really all you can do.

[rollo]

  Had a similar issue with the Audio Research DR 250 Mk2 Servo [ 32 ] tubes. With the Pipedream speakers tube rush [ Hiss ] was evident. Drove me wacky.
   When we replaced the output tubes it went bye bye.
Your in good hands with all the help here. 



charles
SMA

[ltr317]

Deepak,

If you like those tubes, try cleaning the pins with fine sand paper or emery cloth.  Sometimes the pins just develop oxidation.  Most often the tube rush will go away or become greatly reduce when the pins are clean of oxidation.  It's successful about 75% of the time from my experience of cleaning thousands of tubes.  The other 25% of the time nothing helps so they get tossed.   

Paul