Tube dampeners on ARC gear ... FREE TWEAK

Wanted to report on my experience with Herbie's dampers on my VTL MB450-III power amps

Having had good results with the UltraSonic Rx dampers on my phono and pre I wanted to try something on my (currently undamped) power amps. As these run pretty hot I reached out to Robert for advice -- he said the UltraSonic Rx would work even in a power amp but that some users had had better results from the (somewhat more expensive) HAL-O III dampers so I elected to go with these -- quite a lot of money for the 16 size 50 and 4 size 9 I needed

Relative to the Rx the HAL-O are a little harder to use as they do not have the rubber grommets instead with a titanium to glass contact you will have to be firm to get them on

At first listen they seemed a little edgy and I was wondering if the Rx would be better but as the system has settled in these dampers have brought a quite impressive change. If I could sum it up in one word it would be 'control' -- every note is now vice precise and crescendi that had previously resulted in grain and noise now are completely clean. A vocal line alongside highly modulated bass is clear and independent and on mono records (btw a great way to test the effect of these dampers) you have a much improved ability to pick apart all the elements -- one of my test tracks (don't laugh) is "Mr Sandman" by the Chordettes (this is an old Ken Kessler favorite -- give it a try, with the HAL-O IIIs you can easily discern each voice and hear all the details in the backing tracks

The one downside I see is that these things are so damn revealing that the limitations in my (pretty fancy) CD front end are laid clear -- maybe some fine tuning of the filters I am using can ameliorate this, I'm currently using a wide open filter so may now be hearing some of the high frequency filter effects that had previously been masked

Anyway again highly recommended

Frank,

I've been playing with the Herbie's dampers for a few days now, however, they don't work well in my system.  The bass was more solid and soundstage was more focused but I lost the extended high and smooth mid at the same time.  As you know I listen to a lot of female vocal and those are the things that matter the most to me.  I tried to play around with the damper position on the tubes but they just don't sound right no matter what I did.  I think I will send them back unless you have some tips that you can share again.  As soon as I removed the dampers, my system is back to normal again.  It seems like the Herbies are overdamping my system.  Meanwhile, I inserted only 1 ARC ring back into each tube and I noticed the high/mid are still good but the bass is more solid.  So it's like getting the best of both worlds.  Let me know what you think.  Thx.

Allan

folkfreak ...

Wow! That's a lot of tube dampeners. Odd, isn't it, that you're getting some real improvement from dampening so many tubes and yet in Allan system, he's getting over dampening as a result. 

Allan ...

I think its possible to over-damp with some of these tweaks. Based upon my positive results by switching to the Herbie dampeners in the preamp, is hard to imagine that they would be a problem though. Nice that Herbie has the return policy.  

I have Herbie's tube dampeners coming in Monday's mail for the power tubes in the phono, preamp an CD player. I'll report the results here. Hopefully, they will make further improvements. 

Frank

I suspect most people will find that Herbies tube dampers are quite sensitive to where on a particular tube they are placed. For example, on medium/large output tubes like 6SN7 the Herbies damper should sound correct/best when placed where the getter is located, which for bottom getters means on the lower portion of the tube. Also suggest trying placing the Herbies damper on the base itself instead of the glass. For small tubes the ideal location is usually but not always about 2/3 of the way up the tube. Also, when using many Herbies can I suggest trying one at a time, evaluating the sound incrementally. Otherwise, it's like tying to solve three simultaneous equations in four unknowns.

Geoff,

Thanks for your suggestion.  I did play around with the position for the Herbies dampers but nothing seemed to release the high/mid back to my system.  I guess my case is a little different than most of you here in the forum where you guys are using them on traditional preamps and power amps.  I am using them on a pair of PCC88s acting as a input stage for the PS Audio BHK 250 power amp.  It is not really a tube amp but a hybrid.  I guess I will send them back.

Frank,
I am placing an order of 4 Red fuses to replace the rest of the rail fuses in my amp since they are on sale now.  I am not sure if the Black fuses are twice as good as the Reds.  What do you think?

Allan