Tube Dampening a worthwhile tweak?
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HiGHFLYiN9

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I'm pondering what possible accessories may be a worthwhile investment for my EddieCurrent HD300 when it arrives in a few more weeks. The tubes it uses are 1 6SN7 and 1 6AS7. I saw these HAL-Os advertised in audiogon http://herbiesaudiolab.home.att.net/index.htm
and the 45X appears to fit the 6AS7, although i didn't find one for the 6SN7. I have a few questions...

Should both tubes be dampened? If so which model would fit the 6SN7?

Are there better dampeners than the HAL-Os at similar pricing?

Is it worth the relatively small investment? Has anyone elicited notable gains in performance using these?

Are there any other tweaks that are recommended for Tube amps besides rolling?

Thanks!
 
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sacd lover

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hal-o 27 for the 6sn7
hal-o 35x for the 6080 and 45x for the 6as7.

Yes it would be best to damp both tubes. If you were only going to damp one I would do the 6sn7 driver tube. Driver tubes do more amplification so they have more effect on the overall sound. The 6sn7 tube also has a reputation for being microphonic.

As for other dampers you can get several different types. Some are cheaper and some more expensive. Whats nice about these dampers are they are easy to get on and off. All of these devices are helpful, but I have never done a direct comparison. For a tube like the 6sn7 which can be microphonic they can make a larger difference for the good. In fact, any tube thats microphonic will benefit more from these than a tube thats not microphonic. I like the ones I have for my ppx3; I get better focus.

Another good tweek is vibration damping to the chassis. I like to use cone points to cut vibration. I also use hockey pucks on the top of power transformers to add weight and make the top panel less resonant. Hockey pucks can make good feet for vibration control and I also use them under hot running gear to get air flow underneath the chassis. They work great under ps audio powerplants. For $.69-$1 this is a cheap footer or chassis damper; and you arent out much if they dont work. I use the pucks for cable lifters to keep the cables off the carpet too. They dont scratch your chassis and you can move them or stack them wherever you feel any vibration. They are strong enough to support most any gear. They blend in well with most gear having black chassis. They would damp the top panel of the power supply on the hd 300 quite nicely.
 
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Gopher

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SACD,

Hockey pucks would have a smaller footprint/be less apparant on top of my components then text books. Out of curiosity, where do you find them for $0.69? I've seen a low of 3 bucks and change.
 
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spaceman

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Quote:

Originally posted by sacd lover

Another good tweek is vibration damping to the chassis. I like to use cone points to cut vibration.


Are these cone points metallic or rubber? I also like your tip regarding the pucks. I have a few laying around here somewhere, so I may as well put them to use.
 
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sacd lover

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The cone points are 1" metal/ brass with ceramic support discs to keep from marring the rack finish. I picked these particular ones up from Music Direct a couple years ago. I use them under my amp and gilmore v2-se currently. I used to use some under my cd transport and dac combo. My extras will find there way under the hd 300 if I end up being able to use it as a preamp. I definitely like to use vibration damping and cone points on tube preamps when they are around the vibrations from speakers. In a case where you use speakers the difference is especially noticeable.

The hockey pucks I buy at Dunham Sporting Goods. They always seem to be on sale here in Ohio, or atleast where I live. I use these on top of the gilmore v2-se x 4/ gilmore v1 x 2 on each case/ sacdmods 555es x 4 on the top plate and x 4 for footers/ 963sa x 2 around the transport and x 4 for footers. I used to use x 4 for feet underneath a ps audio p300( highly recommmended). As I mentioned, I use them under power cords and speaker cables; and I even stack a couple to support a ps audio lab cable that like to pull away from the outlet. They worked extremely well as feet under the old style chassis on the mpx3 too. .
The pucks really come in handy and I just keep finding more uses for them. Try some out.
 
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timoteus

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You don't really want to damp your tubes unless you are having a big problem with microphonics. Having an ever so slight amount of microphonics in a tube adds air to the music and is actually desirable to many people. Overdamping or damping a tube that isn't microphonic will kill the sound to a degree. Experiment a little to draw your own conclusions.
 
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Quote:

Originally posted by timoteus
You don't really want to damp your tubes unless you are having a big problem with microphonics. Having an ever so slight amount of microphonics in a tube adds air to the music and is actually desirable to many people. Overdamping or damping a tube that isn't microphonic will kill the sound to a degree. Experiment a little to draw your own conclusions.


So you've experienced negative effects with dampening your tubes? Has anyone else noticed this besided Timoteus? Not doubting you bro just want to hear a couple more opinions.
 
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darkclouds

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I've bought a bunch of Herbie's tube damper recently and was quite surprise at the sound I am now hearing. It was a definite improvement.
 
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riddley

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Timoteus, how can you tell whether the tubes in your system need damping or not? What sort of undesirable sound characteristics do excessive microphonics cause?
 
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timoteus

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In a really bad case of microphonics you'll hear a constant ringing coming through your speakers or headphones. Damping the tubes may not alleviate the problem when it is this extreme. You'll know it when you hear it because listening to music is near impossible over the sound of an amplified tuning fork.

In a milder case you may have luck damping the tubes to reduce microphonics. Sometimes the tube is picking up vibrations from the power transformer and conducting them through the chassis and tube socket which excites the tube. Possible solutions beyond tube damping are isolating the transformer from the chassis by raising the transformer off the chassis with rubber grommets or specialty damping products, or mounting the sockets using rubber washers. This disrupts the vibrational path from the transformer to the tube. If none of these methods work then I guess you're left with the expense of retubing and hoping you'll get a tube that behaves.
 
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kelesh

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I have an HD300, and I have noticed a very low volume humming in
the right channel. My HD650 headphones do not hum when played out of
my Klipsch Speakers, and the humming is the same for all volumes and
all inputs or lack of inputs on the amp, and it is there with my
roommates HD 580 Headphones as well.

The hum exists with the sovtek 6sn7 and with a sylvania 6sn7 that i
tried. Would replacing the 6as7 tube fix the problem, or is it rooted
elsewhere?

Should I try damping one or both tubes? Is this humming what microphonics is?

I had the amp plugged into a surge protector, and I have also had it
plugged in to my APC CS 500 battery backup UPS. It hummed both times.
The hum does not show up for the first few minutes, but then it starts
and stays.

I'd rather not send the amp back, but this problem is quite annoying
for classical music listening, as the hum can be heard during breaks
and soft parts of the music.
 
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kelesh,

You might have a ground loop problem. Try this: move your amp to another room and see if the hum still persists. If it does there is a chance that something in the amp is picking up the 60Hz hum off of your power internal to the amp. Ask Craig if he has any thoughts on this as I am unsure of the routing of the signal in relation to the power.
 
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kelesh

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it still persists. craig said that since it takes a few minutes to start it can't be a ground problem anyway. would a tube dampener help this problem possibly?
 
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The tube dampeners reduce microphonics, which is for noisy tubes that causes ringing. So a tube dampener would not help you at all. Also, a bad tube can cause hums but this may not be the case. Your best bet is to send it back and have it checked out. By the way, have you followed SIE's advice in trying the amp on different outlets, or even different rooms? Sometimes, an amp can pick up noise from other appliances and especially those dimming room lamps.
 
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