[jgazal]

  el34 and 6ca7 are identical items. (...)

 
Is there any problem using a 6ca7 with beam confining electrode instead of a more traditional suppressor grid?

 

[yawg]

I'd like to share some tidbits from a tube expert on the Hongkong Tube Audio forum about clean power for tube audio gear here. He only uses double shielded industrial power chords with big plugs:
 
"I ran two dedicated circuits from my distribution box to my AV room. (I put that cable I showed some of you in my roof and wall, so it is getting much-more-correct-than-audiophile-power-cord in my wall at an affordable price.)

One circuit is dedicated to solid state diode power supplies. The other is dedicated to vacuum tube diode power supplies. Never the twain shall meet. There is no chance for switching SS diodes corrupting my tube power supplies this way. The speed matters as well. Tube diodes are fast. SS diodes are slow.

If anything has a switch mode power supply, I run that through an industrial isolation transformer. It's not about making switch mode sound good (iso transformer can help) but more about stopping switch mode from polluting everything else.

Heater technology is one of the most massive advances in vacuum tube hi-fi. The conventional hi-fi world is in the Middle Ages because they have not even conceived of heater technology. Where I have separated my heater power from high tension (separate transformers) I also run separate power cords for heater and high tension. And I group the heaters together (away from high tension power cords) so that they have special handling within my power layout."
 
I hope this helps ...

 

[Jones Bob]

Oh there is a TA?

The original 006t was released a while back, don't recall when. Then it was made ROHS compliant and released as the 600tA for the 100V Japanese market, and as the 120/240V 006t Mk2 for export.

Latest is the 006tS. The spec sheet lists it also as an export 120/240VAC model.
http://www.stax.co.jp/Export/SRM006tS.html

 

[milosz]

  I'd like to share some tidbits from a tube expert on the Hongkong Tube Audio forum about clean power for tube audio gear here. He only uses double shielded industrial power chords with big plugs:
 
"I ran two dedicated circuits from my distribution box to my AV room. (I put that cable I showed some of you in my roof and wall, so it is getting much-more-correct-than-audiophile-power-cord in my wall at an affordable price.)

One circuit is dedicated to solid state diode power supplies. The other is dedicated to vacuum tube diode power supplies. Never the twain shall meet. There is no chance for switching SS diodes corrupting my tube power supplies this way. The speed matters as well. Tube diodes are fast. SS diodes are slow.

If anything has a switch mode power supply, I run that through an industrial isolation transformer. It's not about making switch mode sound good (iso transformer can help) but more about stopping switch mode from polluting everything else.

Heater technology is one of the most massive advances in vacuum tube hi-fi. The conventional hi-fi world is in the Middle Ages because they have not even conceived of heater technology. Where I have separated my heater power from high tension (separate transformers) I also run separate power cords for heater and high tension. And I group the heaters together (away from high tension power cords) so that they have special handling within my power layout."
 
I hope this helps ...

Do you have separate transformers from your power company for your "solid state power line" and your "tube power line" too?  If not, every glitch, noise burst, and transverse-mode disturbance on your "vacuum tube power line" is present on your "solid state power line," and vise versa.  These things propagate at near the speed of light. If your your solid state amp generates some kind of noise or spike, it will travel up your power line to the power company's connection and then back down along your vacuum tube power line and into your vacuum tube amp in less than 0.0000002 seconds.  Or in other words, instantly. 

 

[yawg]

  Do you have separate transformers from your power company for your "solid state power line" and your "tube power line" too?  If not, every glitch, noise burst, and transverse-mode disturbance on your "vacuum tube power line" is present on your "solid state power line," and vise versa.  These things propagate at near the speed of light. If your your solid state amp generates some kind of noise or spike, it will travel up your power line to the power company's connection and then back down along your vacuum tube power line and into your vacuum tube amp in less than 0.0000002 seconds.  Or in other words, instantly. 

I just quoted that Chinese "expert". Personally I found that since I power all my gear except my power amps via a big isolation transformer my overall sound experience has improved a lot.
 
I also use an AC filter before my digital gear, CD-player, DAT-recorder and DAC. This seemed to improve the sound, too.

 

[milosz]

My bad.  It didn't register in my senile that you were quoting someone.

 

[greggf]

I'm having a problem with my 007tII amp, and was wondering if anybody here can help me with it.
 
The amp is new-ish.  I got it directly from Yama's.  At random times, one channel - usually the right, but sometimes the left, and never at the same time - will develop a hum.  It does it with both my 407 and 009 headphones.  (Although it's a higher-end hum with the 009 lol.)  It's not just a minor aesthetic issue; it's loud enough to disrupt listening.
 
I've discovered that I can modify the sound of the hum - make it softer - by resting my hand on the top of the amp.  I can make it go away completely by lightly tapping the side of the 007tII's casework.  Sometimes it goes away on its own after a few seconds or minutes.
 
There's a possibly-related second issue.  About 20% of the time, upon turn-off, there's a residual hum and/or crackling sound in one channel only (usually the right one) for up to a minute after turn-off.  It slowly peters out. 
 
Any ideas?

 

[davidsh]

If the hum is reduced while touching the case it might be some kind of grounding problem. Could also be the tubes picking up noise somehow, vibration, radio signals, grounding problems.. Just some suggestions

 

[rgs9200m]

Send it back to Yama and insist on a new one. If the new one does it, you have some issue with your setup, but I doubt it.
Try all different cables and a different circuit and inputs 1 and 2 and a different input source first just to be sure.
Those guys at Yama are good to deal with and I'm pretty sure they will just replace it.

 

[greggf]

Thanks.  I never thought to try different inputs.  Will get out my RCA cables and try tonight.  Different sources produce the same effect, btw.

 

[rgs9200m]

Good luck. Very nice system you have there by the way. Also make sure there are no dimmer switches active on anything on the power circuit; they can cause havoc.
And of course, if I wasn't clear, try it with an outlet somewhere else in your place. Again, best to you. FWIW, after 3 Stax amps (a T1W both 007t versions), I never had any defects,
even after biasing my current one.

 

[blackads]

I'm having a problem with my 007tII amp, and was wondering if anybody here can help me with it.

The amp is new-ish.  I got it directly from Yama's.  At random times, one channel - usually the right, but sometimes the left, and never at the same time - will develop a hum.  It does it with both my 407 and 009 headphones.  (Although it's a higher-end hum with the 009 lol.)  It's not just a minor aesthetic issue; it's loud enough to disrupt listening.

I've discovered that I can modify the sound of the hum - make it softer - by resting my hand on the top of the amp.  I can make it go away completely by lightly tapping the side of the 007tII's casework.  Sometimes it goes away on its own after a few seconds or minutes.

There's a possibly-related second issue.  About 20% of the time, upon turn-off, there's a residual hum and/or crackling sound in one channel only (usually the right one) for up to a minute after turn-off.  It slowly peters out. 

Any ideas?

A few things, does it hum at all when no source is connected? If so, best bet is probably warranty service.

If it only hums with a source, and if swapping cables doesnt help, then the suggestion from the manual is to try connecting the earth on the 007 with the earth on the other equipment - there is an earth terminal on the back, just use the terminal to run a wire to the source, and find a ground point ( eg a case screw you can loosen and retighten to hold the wire).

I have a 727 that I tried with my wa22 as a preamp for a while, when the wa22 was connected via the balanced inputs it hummed noticeably throug the 727 but the common earthing suggestion stopped the hum completely -

 

[greggf]

Doesn't seem to be cables/inputs.  I should mention that the hum is sometimes a light crackle, and also that it's a very random thing.  99.9% of the time, everything sounds fine.  The gear goes to a dedicated audio outlet that is wired straight back to our fuse box.  But our electricity is very strange out here.  We live in a town of about 5,000 people, and we are at the very end of the line - the last folks.  The lights are forever flickering, dimming, etc.  We've had everything checked.  It's not the house, it's the "grid", as such.  Is STAX electrostatic gear perhaps more sensitive to power irregularities?
 
Time for a trip to Yama..........

 

[davidsh]

  Doesn't seem to be cables/inputs.  I should mention that the hum is sometimes a light crackle, and also that it's a very random thing.  99.9% of the time, everything sounds fine.  The gear goes to a dedicated audio outlet that is wired straight back to our fuse box.  But our electricity is very strange out here.  We live in a town of about 5,000 people, and we are at the very end of the line - the last folks.  The lights are forever flickering, dimming, etc.  We've had everything checked.  It's not the house, it's the "grid", as such.  Is STAX electrostatic gear perhaps more sensitive to power irregularities?
 
Time for a trip to Yama..........

Power conditioning might be wortwhile in your case.

 

[arnaud]

  Doesn't seem to be cables/inputs.  I should mention that the hum is sometimes a light crackle, and also that it's a very random thing.  99.9% of the time, everything sounds fine.  The gear goes to a dedicated audio outlet that is wired straight back to our fuse box.  But our electricity is very strange out here.  We live in a town of about 5,000 people, and we are at the very end of the line - the last folks.  The lights are forever flickering, dimming, etc.  We've had everything checked.  It's not the house, it's the "grid", as such.  Is STAX electrostatic gear perhaps more sensitive to power irregularities?
 
Time for a trip to Yama..........

 
Isn't that one or more tubes going south?