[tacitapproval]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif Great. So you are ok now?

Yes. Thanks again.

 

[tacitapproval]

Ok, so I went back and tried the two 6n1p's that had caused problems with the e12, and now they play fine. What gives? I have always been a burn-in skeptic for electronics, but something is working better now without me altering anything. Any theories?

By the way, this little amp is mighty impressive. All of the tubes have sounded quite good so far.

 

[sachu]

Quote:

Originally Posted by tacitapproval /img/forum/go_quote.gif Ok, so I went back and tried the two 6n1p's that had caused problems with the e12, and now they play fine. What gives? I have always been a burn-in skeptic for electronics, but something is working better now without me altering anything. Any theories? By the way, this little amp is mighty impressive. All of the tubes have sounded quite good so far.

Is it possible they were not put in correctly the first time you tried them? They do have longer leads right compared to other tubes?

I would suggest trying to roll those 3 tubes a few more times and check if the E12 is working fine.

 

[wiatrob]

Quote:

Originally Posted by tacitapproval /img/forum/go_quote.gif SNIP...What gives? I have always been a burn-in skeptic for electronics, but something is working better now without me altering anything. .

Were the tubes NOS? No thporetics - Sometimes when things sit around for 20 years or so they need a little juice flowing through them to wake them up. I have seen this with some tubes (channel imbalance, etc, goes away after they burn for few hours.)

Congrats on getting the amp up and running! Enjoy!

 

[tacitapproval]

Yes, they are NOS from the 70s, I believe. I wasn't able to try them out before, because my SOHA II is not configured for higher amperage. I suppose that is it. Glad they work

 

[runeight]

Although I am not a big believer in tube breakin, there is an important activity that takes place in the first 50 hours or so.

Even though the tubes are evacuated they still have residual gas. And there are gases and other crude stuck onto the metals at the molecular level. When they sit for a long time they can get gassy from the small amounts of leakage that occur and from the outgassing of the residual junk in the tube.

Over the first 50 hours the heating due to normal operation causes all this junk to be ejected from the various surfaces where it's all, eventually, collected by the getter.

So over the first 50 hours the tube internally cleans itself and makes a pretty hard vacuum.

It could be, although we are not certain, the the 30 year old tubes just need some runtime to clean themselves up.

 

[TimJo]

I'd say this is true, based on my experience with the NOS tubes I've tried from the late 50's and early 60's. One of them didn't make it more than 20 hours before one channel started to fade away, but the vendor is sending me a replacement.

I do have to say that rolling these old tubes brings a whole 'nuther level to listening to vinyl...

Part of this might be the synergy between my phono preamp and the CTH. The Linto is a moving coil preamp where the coil is directly coupled to the input transistors - no loading network. I'm not sure how many companies have built this style of mc preamp because it is designed to work with very low coil output (25pW) and a specific input impedance. The Benz cart I have is a good match - the s/n ratio is incredibly low and the detail pretty amazing when driving these old tubes. Because of this it is also pretty unforgiving - your pretty much hearing the inside walls of the vinyl groove using a microscope. A record cleaner is a good thing.

I continue to be blown away by the details I am hearing for the first time in really old albums.

 

[Forte]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif It could be, although we are not certain, the the 30 year old tubes just need some runtime to clean themselves up.

Yep, even my limited experience with tubes backs that up.

The biggest change seems to be over the first few hours, but it can be a few days before a NOS tube fully reveals its true sound. Worth the wait though as they usually sound better than the new production tubes I have tried so far.

 

[tacitapproval]

So, this morning, the two 6n1p's I tried at first are again playing for a few seconds and then tripping the e12 and repeating this again and again. The other two (I have four from the same source) are ok and stable. I assume the two are just dodgy (Unfortunately, I don't have a tube tester). But, why would they not work, then work (they played stably for at least fifteen minutes a piece last night), and then not work again. The only guess I have come up with is changes in atmospheric pressure or humidity? Any other ideas? Is it possible they will work more stably if I burn them in longer?

p.s. Sorry to thread hijack--I think I have safely determined that it is not the CTH that is at fault.

 

[holland]

Was your amp hot or cold in those situations (yesterday morning, last night, this morning)? Does the behavior change as the amp (and or tubes) warm up?

Can you ground your input? Take a 3.5mm male to 3.5mm male adapter Tape a resistor leg across the contacts on one end and insert the other into the amp input. This grounds the inputs. Does it still trip?

 

[tacitapproval]

I went to try your suggestion, Holland, and, you guessed it, the e12 is not being tripped now.

In terms of warmness, I suppose the amp may have been on a bit longer when the tubes have worked, although I haven't enclosed it yet, so nothing is appreciably warm, save the regulator. Also, the tubes would not be any warmer as they trip the e12 right away, or don't right from a (cold) start.

 

[Giuss]

Quote:

Originally Posted by runeight /img/forum/go_quote.gif I guess to suggest the obvious, and not necessarily to push the products, but if you were to buy a kit you would get all the necessary components.

Ok thanx, but I'm not sure if is convenient to order the kit from Italy for shipping and custom costs

Bye

 

[holland]

Quote:

Originally Posted by tacitapproval /img/forum/go_quote.gif I went to try your suggestion, Holland, and, you guessed it, the e12 is not being tripped now. In terms of warmness, I suppose the amp may have been on a bit longer when the tubes have worked, although I haven't enclosed it yet, so nothing is appreciably warm, save the regulator. Also, the tubes would not be any warmer as they trip the e12 right away, or don't right from a (cold) start.

I see. I was just curious if you had any cold joints. The other was to see if you were getting any spurious events happening while the amp is (externally) in a quiescent state.

One thing, though less of a problem solving point but more of a problem identification, is if you can isolate a music track that trips the e12 consistently. Is it always in the same spot(s) where it trips?

For the tube that does work, using the same tracks, what happens if you turn it louder? Does it trip in the same way?

 

[tacitapproval]

I think you are on the right track with the grounding. I think it is related to external devices. I say this because, I noticed that it happened one time (after a period of stability) when I printed something (printer and computer on the same outlet as the CTH). This doesn't happen with other tubes because of 6n1p's greater current draw? I will try different outlets and see if it changes.

It doesn't follow specific music or volume. In fact, it can happen while no music is playing.

 

[sachu]

Quote:

Originally Posted by tacitapproval /img/forum/go_quote.gif I think you are on the right track with the grounding. I think it is related to external devices. I say this because, I noticed that it happened one time (after a period of stability) when I printed something (printer and computer on the same outlet as the CTH). This doesn't happen with other tubes because of 6n1p's greater current draw? I will try different outlets and see if it changes. It doesn't follow specific music or volume. In fact, it can happen while no music is playing.

well apart from the hiccups with the 6N1P..how does the amp sound?