[yakaway]

Re: biasing stax srm-007tII

The right trv3 reads 045 on the (2000mV) indicator of the multimeter. This is with the screw turned all of the way. Is an acceptable value?

Everything else reads zero! Here's to small wins.

I'm about to take this thing to the shooting range. I put the stock russian tubes back in and did the biasing. I think that's the best i can do.

If this is no good, I guess I'm buying blue hawaii

Thoughts?

 

[JimL11]

Re: biasing stax srm-007tII

The right trv3 reads 045 on the (2000mV) indicator of the multimeter. This is with the screw turned all of the way. Is an acceptable value?

Everything else reads zero! Here's to small wins.

I'm about to take this thing to the shooting range. I put the stock russian tubes back in and did the biasing. I think that's the best i can do.

If this is no good, I guess I'm buying blue hawaii

Thoughts?

That is fine for now, however if you had to turn TRV3 all the way, it sounds like that tube is marginal as there is no adjustment range left. BTW, sorry about my previous post, must have gotten up on the wrong side of the bed.

 

[Whitigir]

Re: biasing stax srm-007tII


If this is no good, I guess I'm buying blue hawaii

Thoughts?

I totally recommend this

 

[SeaWo|f]

I second that recommendation.

 

[yakaway]

Not a problem at all Jim. I apologize for being so naive about all of this. I never considered this as a hobby until very recently. The learning curve is astronomical, but I find it enjoyable nonetheless.

I have so many questions as a newbie and I greatly appreciate those who take the time to offer their insight.


For one, with the SRM-007tII I get crosstalk between the inputs. Meaning, if I turn the volume up very high and am listening to channel two, I will hear the sound on input 1. Is this normal with such an amp? Is this a grounding issue? While it should not be a big deal, I am surprised to hear it.

Also, can anyone compare/contrast this bass when upgrading from say the 007tII to a BHSE or something on that level? I feel like I’m hearing wonderful mids and highs with the 009s, and great separation. I hear all of the instruments with great detail, but I find the bass lacking. I’m aware that the 007s may offer more bass, but currently I own 009s and plan to stick with them for quite a while.

Lastly, is there a technical way to balance the left and right channels or do you just rely on your ears for what sounds good? There is a knob in addition to the volume knob on the right of this amp for controlling the balance. I turn it all the way to the left and the volume is loud on the left. I turn it all the way to the right and it is certainly not as loud in the right when compared to the left.

I find this frustrating, but I’m not sure much is to blame on the amp, my lack of technical know-how, or the headphones.

Helpful and positive comments area greatly appreciated.

 

[SeaWo|f]

While I have had limited listening time with the 009 out of the bhse I did not find the bass lacking. I however did not listen to anything bass heavy like edm. It felt right for the rock/pop I put through it.

I have read some subjective impressions that with the 009 a carbon gives more impact vs a bhse. Idk if anyone who has experience with both could give their thoughts.

 

[kevin gilmore]

The right trv3 reads 045 on the (2000mV) indicator of the multimeter. This is with the screw turned all of the way. Is an acceptable value?

No it's not acceptable. That can be up to 1ma, more than 10% of the output current. There will be differential gain, there will be phase issues.
Replace the tube.

 

[yakaway]

Thank you Kevin. Do you mean the rear tubes, or all of them?

 

[joseph69]

Thank you Kevin. Do you mean the rear tubes, or all of them?

Why would you not buy all new tubes? This way you have piece of mind knowing all of your tubes are new.

 

[1note]

if tvr1 is all the way to one side or the other parts including R13,R14,Z1,Z2 may burn up.
Put all pots in the middle and start again.

Note: the way the srm-007t works is different from the tA and tII
On the 007t tvr3 and tvr4 should be set to 200 ohms (500 ohm pot). on the tA and TII it should be set in the middle. (2k pot)

Repeat the following a few times over 30 minutes
Then put a voltmeter between TP1 and TP2 and adjust TVR1 for zero
(if you have to turn tvr1 more than .25 turn in either direction, stop and get new tubes)
Then put a voltmeter between either TP1 or TP2 and Ground and adjust TVR2 for zero
Then put a voltmeter between both TP1 and adjust TVR3 to zero
Then put a voltmeter between both TP2 and adjust TVR4 to zero
end repeat

If you can't get the last 2 to zero, then get better tubes. Seriously just because someone sold you some expensive NOS tubes that they said were matched...

Hi Kevin,
Sorry for the dumb arse question but I would be most grateful if you could confirm that the procedures you describe in your post above are the total procedures for adjusting a TII after replacing the 4 tubes.
Many thanks,
Chris

 

[yakaway]

Why would you not buy all new tubes? This way you have piece of mind knowing all of your tubes are new.

I literally received my 009s and 7tII last week used. I have zero experience with electrostatics. The guy sent them with vintage (non-russian) tubes that he called an upgrade. One of them was damaged in shipping is my guess.

He sent the standard (russian) tubes over the weekend. I was hoping to bias them and resolve the issue. It seems I've had no luck with that either.

His recommendation was to put two vintage working ones in the back and 2 newer ones in the front
Likely, I'll be buying tubes very shortly.

If anyone can recommend quality tubes for this, that would be very helpful.

 

[kevin gilmore]

You replace the one tube that won't balance. But really a matched quad is much better.

The problem is that you need tubes with well matched sections. Just because a tube is new or " an upgrade" does not mean the sections are well balanced.
And if the sections are not well balanced, you can't use that particular tube in this circuit no matter how expensive or rare the tube is.

much easier to buy double the amount of new cheap tubes you need and pick the best of the bunch. Even that might not be good enough.
The T8000 is much worse with respect to this.

Its possible although very unlikely that the circuit is damaged. If a tube balances in one position, but won't in another, then there are circuit issues.

 

[statfi]

pick the best of the bunch

Which used or new tube testers should we look for (to purchase) that would be good for "picking" tubes out of a "bunch"? Thanks in advance!!!

 

[kevin gilmore]

the uTracer 3+ is what you want. But its a kit and you have to assemble it yourself. Transformer, Chassis etc.
unless you build something custom, its the only to way to set a grid voltage and measure plate current.
Which is what you need for the 007 because you want to match for 3.7 ma per plate at a constant grid voltage.

old style tube testers are a lot harder to use for this.

 

[statfi]

the uTracer 3+ is what you want

Oh wow. Am I glad I asked! Thanks!