Crispy
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Madrigal music is playing - Voices can faintly be heard, "Please leave this patient undisturbed."
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Post by Crispy on Aug 10, 2015 17:18:40 GMT
Here's an interesting video showing the art of valve manufacturing.. Thats a very interesting video Gordon, I never realised how much work goes into making just one tube - I honestly thought they were mass produced by some machine  It's a wonder they don't cost an absolute fortune all the work that goes into making them. |
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Deleted
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Post by Deleted on Aug 10, 2015 18:44:14 GMT
I had assumed the same. I don't feel nearly so bad spending the money asked now. I also didn't realize they got quite so big either.
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solderdude
Administrator
measureutternutter
Posts: 4,886
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Post by solderdude on Aug 10, 2015 21:34:07 GMT
The guy in the video just makes these tubes for fun.
Most tubes are simply made in a factory
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Deleted
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Post by Deleted on Aug 10, 2015 22:10:14 GMT
Killjoy  |
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Post by skyline on Sept 8, 2015 19:12:50 GMT
I've had an Amperex 6dj8 with me for the past week or so that I really enjoy. Everyone raves about the ones from Holland and this one was made in Great Britian. I couldn't for the life of me figure out what this was...didn't seem like Orange Globe or Bugle Boy. I finally realized that it's actually a Mullard, with an Amperex rebranding: www.ebay.com/itm/Pair-Blackburn-Mullard-Amperex-A-Frame-6DJ8-ECC88-tubes-Tested-80-78-77-81-/181284040883?hash=item2a355ef0b3' Highly recommended. It doesn't do any one thing better than any other tube...not the best soundstage, not the most detailed, etc. But, it puts together a really nice overall package. The sound is very cohesive and involving. My Sylvania 6SN7 beats it in both clarity and soundstage, but the bass is a bit elevated whereas the Mullard/Amperex seems to put it in balance with the rest of the sound. It's been fun bouncing back and forth between the two. Now, onwards and upwadrds (or perhaps sidewards) to the Russian 6N6P that Jeremy has recommended to me. |
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howie
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Posts: 158
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Post by howie on Sept 13, 2015 8:07:31 GMT
Something horrible happened to me this morning.
I thought I knew my Horizon inside out. I put in a new Tung-Sol 12AX7 and although the sound was excellent there was a huge amount of vol pot noise. For the first time ever I invoked the input capacitors and was shocked to lose all sound in one channel, and most of the sound in the other. Sweating and shaking I frantically fiddled around and became convinced I would have to send the amp back to Jeremy for a repair when I heard a quiet but familiar whine I associate with poor biasing. That was the problem-the bias voltage had risen from 20 to 38V! All was well after adjusting it back down again.
Then I read in the instruction manual you have to re-bias after using these jumpers-there's always something to learn about tubes-even on a Sunday.
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Deleted
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Post by Deleted on Sept 13, 2015 9:27:35 GMT
It's times like that you appreciate just how comprehensive and well written the Garage1217 manuals are. Glad it all worked out okay  |
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howie
quite active
Posts: 158
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Post by howie on Sept 13, 2015 9:55:42 GMT
It's times like that you appreciate just how comprehensive and well written the Garage1217 manuals are. Glad it all worked out okay Thanks, and you are so right-Jeremy and Frans explain everything- just a shame I forgot what I had read a year ago! I'm now relaxing to 22 Volts per channel of Bach. Cheers. |
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howie
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Posts: 158
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Post by howie on Sept 17, 2015 17:57:30 GMT
Now I've recovered from the shock I've become a bit obsessed about tube biasing.
Obviously it's a no brainer for the self biasing Ember but for the other G1217 amps you set the bias manually.
The advice is 12V for the Starlight and 22V for the Horizon. My question is how critical are these figures-would 2-3V either side matter to the sound or the longevity of the tube, as long as it sounds alright, (as it does to me)?
Some amp manufacturers even say the tube will self bias in their amps-how does a tube do that?
When biasing my Horizon manually the bias voltage, with both biasing leds unlit, are at 20.5V for 6SN7's and 24.5V for 9 pins-it's a bit bewildering. Can anybody help or maybe guide me to a website/link that will answer such questions?
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Post by tunkejazz on Oct 3, 2015 20:41:52 GMT
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howie
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Posts: 158
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Post by howie on Oct 3, 2015 21:17:44 GMT
When I first got Ember I tried many different 9 pin tubes that I already had and that 6H30Pi was one of them. The only thing I can tell you is that I made a note that it sounded 'excellent-a good all-round tube'. From memory, they are a little less warm, and clearer and more dynamic than the 6H6P's, but please take that with a pinch of salt as I also made a note that the 6H6P's were also excellent in the Ember. Actually, most tubes I try sound very good/excellent in the Ember-it's that sort of amp, bringing out the best in the tube I guess. |
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solderdude
Administrator
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Post by solderdude on Oct 3, 2015 21:26:44 GMT
Now I've recovered from the shock I've become a bit obsessed about tube biasing. Obviously it's a no brainer for the self biasing Ember but for the other G1217 amps you set the bias manually. The advice is 12V for the Starlight and 22V for the Horizon. My question is how critical are these figures-would 2-3V either side matter to the sound or the longevity of the tube, as long as it sounds alright, (as it does to me)? Some amp manufacturers even say the tube will self bias in their amps-how does a tube do that? When biasing my Horizon manually the bias voltage, with both biasing leds unlit, are at 20.5V for 6SN7's and 24.5V for 9 pins-it's a bit bewildering. Can anybody help or maybe guide me to a website/link that will answer such questions? I totally missed this question... The Bias voltage for the amps is not very critical. A reasonable exact set bias voltage will give symmetrical clipping when clipping levels are reached. In most cases nobody will ever come near clipping levels unless playing very loud with high impedance headphones or very inefficient headphones. So +/- 2V is no problem for Horizon but would like the Starlight and SR closer to +/-1V (when warmed up) Self biassing in tube amps works VERY differently than in G1217 amps. In these amps the power supply voltages are well over 200V and it really doesn't matter if the anode voltage is off by 50V or so as the voltage swing needed for audio will be relatively small in amplitude. The self biassing in tube amps is very easy and consists of a cathode resistor. When the tube starts working a current flows and the voltage that is created pinches off the tube itself and so it settles at a certain anode voltage (that isn't that critical) Here the anode 'current' is selfbiassing (and thus also the voltage across the anode resistor, not the anode voltage) For G1217 amps the anode voltage is critical because the voltage swing needs to be as high as possible and symmetric. The 'biassing' of G1217 amps thus is NOT the same biassing as what occurs in all tube amps. It just uses the same names. In all tube amps the voltages AND currents are MUCH higher and thus also the consumed power. In all tube amps the tubes operate near their maximum 'abilities'. In G1217 amps there are very low currents and voltages and thus the tubes are in no way stressed nor will they even when the bias voltage is completely off. In all tube amps this might cause tube failure. In G1217 amps it is impossible to destroy a tube. The different voltages for proper bias in Horizon are unexpected. They should be the same voltage. Both LED's need to go off and then turn the post slightly so the 'high' LED just barely lights up. That should give almost the same values for both tubes. Perhaps measure the power supply voltage with both tubes and see if in both cases the power supply voltage is stable at 48V. |
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Post by tunkejazz on Oct 3, 2015 21:45:01 GMT
When I first got Ember I tried many different 9 pin tubes that I already had and that 6H30Pi was one of them. The only thing I can tell you is that I made a note that it sounded 'excellent-a good all-round tube'. From memory, they are a little less warm, and clearer and more dynamic than the 6H6P's, but please take that with a pinch of salt as I also made a note that the 6H6P's were also excellent in the Ember. Actually, most tubes I try sound very good/excellent in the Ember-it's that sort of amp, bringing out the best in the tube I guess. Thanks howie, that is my impression too with most tubes. But in many cases there is something very subtle that makes a tube not be used: a tad too little bass, a tad too bright, a tad too dull...Always very subtle, but subjectively noticeable after listening for a while :-) I have a set of tubes on loan from a friend here in Stockholm, but I only own 3x6SN7 + 2x7193. All this talking about Russian tubes made me curious and they are much cheaper than most other tubes :-) I would not mind getting one. The problem is that it looks like one must get them from the right years...which of course is trickier. I would like to try something from the 60-70's very dynamic and well extended/present in the bass (yes, I must be developing some kind of basshead syndrome :-P ). The question is which one? 6N6P, 6N1P-??, 6H2P-EB, ... Well...In the mean time I put my Vali for sale to rise some funds for the Polaris, I am not using it anyhow. At home I have a pair of Denon D2000 and the Vali shows a horrible noise floor with those. |
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solderdude
Administrator
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Post by solderdude on Oct 4, 2015 7:16:19 GMT
You can audition the Polaris if you want.
The only costs are the shipping costs involved.
You can have it with you long enough to evaluate it thoroughly.
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howie
quite active
Posts: 158
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Post by howie on Oct 4, 2015 7:21:21 GMT
I agree that subtle differences can make or break a tube's use-but for me, liking a huge range of Classical stuff, means there are a lot of different sounds to cater for. As far as Russian Tubes go, my understanding is that as long as the tube comes from the 'cold war' era it probably doesn't matter too much who made it as most were made for the Military and the quality was very consistent during that time. Maybe someone who knows more about Russian tubes could add to our discussion? I do have some '60's 6N6P tubes from the Reflektor Factory which are very good. Again, looking at those notes of mine, I see I thought the i version had a bit more depth and treble, and the ir version slightly less depth than the 6N6P, so a 6N6P might be best for bass. However, this was a very quick assessment in the euphoric phase of having a new Ember amp-and with a K612. Your own kit ( and ears) could be very different. |
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