[zardon]

I thought I would share some of my thoughts on various amplifiers and headphones, including the BHSE and Stax 009. It is a little long to post here, so you can read it here. http://www.kitguru.net/site-news/highlights2/zardon/flagship-headphone-amplifier-round-up/

 

[bmichels]

  I thought I would share some of my thoughts on various amplifiers and headphones, including the BHSE and Stax 009. It is a little long to post here, so you can read it here. http://www.kitguru.net/site-news/highlights2/zardon/flagship-headphone-amplifier-round-up/

 
wonderful review.  thanks a lot.

 

[TheAttorney]

Yes, very well presented reviews zardon. I think that tube rolling in the BHSE is more significant than suggested here, but it will be more subtle than comparing amps or headphones, so the benefits of tube rolling will become more obvious once the other variables are removed. So I agree it wasn't the place to swap tubes in this kind of multi-way comparison.

 

[arnaud]

I used to feel large differences between the tubes I rolled in (xf2 OO, xf4 DD, brimar/mullard/telefunken origin).
I am now more confused than anything else. Seems like they all start to sound more similar than different after I put hours into them.
Nowadays I try to keep a set for several sessions before I switch but it's not making differences any more obvious. On the other hand, changes in my upstream gear become very clear after a few weeks of usage.
To those who are lost, I'd thus recommend to score a couple of NOS sets among those recommended in this thread other the years but not sweat it. You source material and player matter much more than the tubes imho.
Cheers,
Arnaud

 

[carl99]

On that note, I am one of those who would like to bias; I have watched "the video" a number of times, but am reluctant to start until I know exactly the make and model of the voltmeter that I should buy.
Can I get a recommendation?
Thanks in advance.

 

[Crashem]

pretty much any voltmeter will do. Just make sure it goes to 1000V.
 
I bought this one:
http://www.amazon.com/Etekcity-MSR-U1000-Autoranging-Multimeter-Non-contact/dp/B00NW62L88/ref=sr_1_15?ie=UTF8&qid=1459963826&sr=8-15&keywords=voltmeter
 
Funny thing is that I spent 10 minutes trying to figure out how to set it for 1000v before I realized it was auto ranging (ie i don't have to set it).  just turn dial to voltmeter and set sensitivity and away you go.

 

[carl99]

Thank you.
Much appreciated!

 

[Sko0byDoo]

Why messing around? Get a Fluke (87V).

 

[Crashem]

  Why messing around? Get a Fluke (87V).

 
Flukes are expensive but accurate .
 
The one I listed is around $40.  A pure voltage meter would be even cheaper if you can find one.  They all seem to be multimeters now.  In any case, I wasn't used to auto ranging as when I last bought one of these devices, they weren't so fancy.  Fun trying to get bias to 1/100 of volt to 0. 

 

[bearFNF]

Yeah, I use a fluke 87V, also. But I do DIY circuits stuff, too.

Agree the auto ranging ones are a little tricky, as they keep changing range as you adjust. Better to find one with less bells and whistles that still allows manual range section.

 

[georgep]

Agreed that the 87V is nice (I have one myself), but that would be crazy overkill for something like this. And although you probably can't get much cheaper than the $40 one identified, I wouldn't think it would need to be able to handle 1000v. The highest voltage you could encounter at the jack is 380v on the bias line (which you shouldn't need to poke around in if you are just setting balance and offset). The + and - left and right should be very low voltage, likely well under 50v in each case.

 

[bearFNF]

I think the 1000V scale is just to help with getting a zero reading. It reduces the sensitivity of the measurements to the adjustment.

If you set it to auto then it will bounce to mV when you get close to zero.

It also reduces the precision but still gets you within +/-1 volt on the meter.

 

[georgep]

But a lower rated DMM will do that too - its about resolution, not max working voltages.

 

[bearFNF]

The point I was trying to make is that 1000 volt scale it would only read 1 volt increments so it's a lot less sensitive two minor changes of the pot.
If you watch Justin's video on YouTube you can see this demonstrated.

Of course that depends on what meter you get and how many digits it actually reads.

You can drive yourself crazy trying to get it 000.000, you'll never get there anyway.

I adjusted mine until it was within .7 and call it good. It also drifts so it will change over time.

 

[arnaud]

Just sligthly blowing air (window open / air breeze or air conditioning) on the tubes makes the dc offsets swing by hundreds of mV (don't remember which, might have been stator to ground), just like these offsets drift drastically with warmup as discussed above (at least the stator to stator offset).

On my side, I only do a check/adjustment after 5min the first time I try some tubes, for safety because I can't test tubes. I do another adjustment after a couple of hours once warmed up as recommended by justin in his tutorial video. I don't typically check offsets after that until I swap tubes again.

Actually, for NOS tubes, although I have not tried that many of them, I typically don't need to adjust the pots significantly. The PSVANE on the other hand required different adjustments I recall (I seldom put them in nowadays).

Cheers,
Arnaud