Lampizator Valve / Tube Rolling Review Thread

[Alrainbow]

Correct the meter setting to amps means the leads are shorted so yes not good
But if meter is set to dc voltage rhis is fine and has a very high resistance so no clicking. try it ok. Even post a pic of meter before you try it

 

[dminches]

Correct the meter setting to amps means the leads are shorted so yes not good
But if meter is set to dc voltage rhis is fine and has a very high resistance so no clicking. try it ok. Even post a pic of meter before you try it

Thank you. I will do this today.

 

[dminches]

Ok. So here is what is very interesting.

I measured the voltage of both Tesla AD1ns on both the 300B and 101D settings.

300B 101D

Good Tube 5.023 4.969
Bad Tube 4.993 4.099

So, for some reason, the "good" tube is pulling 5V even on the 101D setting. This is resulting in it playing louder than the "bad" tube. On the 300B setting they are pulling the same voltage and are playing at the same volume.

What is going on here?

@adamaley , @Al M. @User211

 

[Golum]

Ok. So here is what is very interesting.

I measured the voltage of both Tesla AD1ns on both the 300B and 101D settings.

300B 101D

Good Tube 5.023 4.969
Bad Tube 4.993 4.099

So, for some reason, the "good" tube is pulling 5V even on the 101D setting. This is resulting in it playing louder than the "bad" tube. On the 300B setting they are pulling the same voltage and are playing at the same volume.

What is going on here?

@adamaley , @Al M. @User211

View attachment 68455

Uber strange...

 

[Zero000]

I have just measured AD1n will post in about 1 hour messing around with some vintage Accuphase M-60 monos at the moment!

 

[Golum]

David while at it could you kindly measure RDs?

 

[Zero000]

Right, here's what I just did.

First I measured the resistance of the multimeter leads by touching them together.



Then I measured the filament resistance thus. It's low Ohms and the result is a bit variable because of it I think. Some pics to show variance:





What you are supposed to do it subtract the lead resistance from the filament measured resistance so let's say we have a 1.9 Ohm filament from those readings.

 

[Zero000]

Then I measured the voltage. You see two shots with each OJ date code AD1n in the same slot. In my tube tester they both measure 6mA/V if I remember correctly.

They both measure bang on the same voltage here. A bit closer to spec than David's Pac, but hey, the guy who did my DAC is freakin' awesome, LOL.




So, from V=IR we can deduce that 4.53 / 1.9 = a current of 2.38 amps. Which is pretty closeish to spec.

So that's pretty good as far as I am concerned.

 

[Zero000]

Ok. So here is what is very interesting.

I measured the voltage of both Tesla AD1ns on both the 300B and 101D settings.

300B 101D

Good Tube 5.023 4.969
Bad Tube 4.993 4.099

So, for some reason, the "good" tube is pulling 5V even on the 101D setting. This is resulting in it playing louder than the "bad" tube. On the 300B setting they are pulling the same voltage and are playing at the same volume.

What is going on here?

@adamaley , @Al M. @User211

View attachment 68455

Measure the filament resistance of both AD1n as I have above and post the results David.

But yeah, it does look odd. It's like your bad tube is behaving better than the 'good' one. The 'bad' tube is bang on on 101D. Way better than I am getting.

Mind you my meter is a POS.

 

[dminches]

David while at it could you kindly measure RDs?

I get 3.97 and 4.02 on the 101D setting.

 

[Zero000]

You say the problem moves with the tube as you swap the sockets don't you David?

 

[Zero000]

I get 3.97 and 4.02 on the 101D setting.

That's brilliant.

 

[dminches]

Measure the filament resistance of both AD1n as I have above and post the results David.

But yeah, it does look odd. It's like your bad tube is behaving better than the 'good' one. The 'bad' tube is bang on on 101D. Way better than I am getting.

Mind you my meter is a POS.

More interesting information.

On the "bad" tube I am getting a resistance of 1.4. The meter is .1, so the true resistance is 1.3.

Based on a voltage of 4.099, the implied current is 3.15 amps, which seems high.

On the good tube I can't get a reading. The meter just reads OL on one meter and no reading on the other.

I think what I am concluding is that the "good" tube is bad and the "bad" tube is fine.

 

[dminches]

You say the problem moves with the tube as you swap the sockets don't you David?

Yes. It isn't the DAC.

 

[Zero000]

The RD reading seems to imply there is some issue with the AD1n 'good' tube (it's actually the bad one). But it's not that simple if adamely has the same issue I wouldn't think.

See what Al thinks.

 

[dminches]

The RD reading seems to imply there is some issue with the AD1n 'good' tube (it's actually the bad one). But it's not that simple if adamely has the same issue I wouldn't think.

See what Al thinks.

That's my thought too. The "good" tube is bad.

 

[adamaley]

@Golum I've been trying to respond to your PM but the system isn't allowing me to submit it here.

So, I received the tubes (AD1ns) from Luke and, as some may recall, started off using the 300B setting. A day or so later, I was informed on here that the 101D setting was the appropriate one to use. After switching to that, I noticed a channel imbalance so I assumed the tube on the low volume channel had issues, and I requested a replacement from Luke (tube source). While waiting, I purchased a new single AD1n from eBay, and it played just fine in 101D mode with the stronger of the two original tubes. I've been super busy and not able to listen to much audio over the last few months, so experimentation and testing hasn't been possible. After a while though, the imbalance was creeping in again. After speaking to @dminches about what he was experiencing, I decided to try the 300B setting, and lo and behold, everything sounds perfect, regardless of how strong the tube is.

@dminches and I are both confounded with our findings and we leave things up to the higher powers to decipher how the tubes are being heated and why the 101D heater setting is reacting this way. My suspicion is that if two tube are close enough in testing, they will sound equally loud in that setting.

We also considered that performance could be related to the pins on the bases - some have holes in them, and if one of the 4 pins that are active (the others do not play a role in heating the tube) has a hole in it then this issue may occur. We have spoken about possibly soldering the pins to test this out, so all in good time.

Edit: I had already typed all this out before the good tube is bad and bad is good hypothesis came up, and forgot to hit send.

 

[Zero000]

My honest advice as earlier remains the same. Use the 300B setting.

What I will do is ask the chap who did my DAC to read this thread and see what he thinks.

 

[Golum]

I get 3.97 and 4.02 on the 101D setting.

Thanks David...won't ask for any feedback about tubes until you break in the dac fully

 

[adamaley]

To those not having issues with the AD1n on the 101D setting, can you give some info on the strength of your tubes or what the bottom pins look like?