Deleted
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Post by Deleted on Apr 2, 2015 14:54:52 GMT
Hi Bob. That is a superb piece of work! The photography is also fabulous.
Might I ask where you sourced the knob?
Gordon.
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obo78
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Post by obo78 on Apr 2, 2015 15:56:11 GMT
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Post by Deleted on Apr 2, 2015 16:09:35 GMT
Thanks for the links Bob. That grinding noise you can hear isn't from one of your wonderful clockwork macros but rather, my mind trying to work out how to import one of those knobs to Scotland
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solderdude
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Post by solderdude on Apr 2, 2015 16:54:49 GMT
It's funny to see that often people that like audio toys are often also interested in photography and watches.
I also have a fondness (and repaired) analog mechanical cameras as well and had been in photography quite a while. Not nearly as nice a portfolio as yours though ... mostly did wedding photography for people I knew or asked.
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Post by ronzo56 on Apr 2, 2015 18:32:09 GMT
Richard 51- Yes, I use the socket saver with the adaptor and I have had no problems other than it sits a little high up. Looks like a rocket. I did forget to mention that the socket saver pins don't go all the way into the Embers socket I think the pins are a touch long for that particular socket. Doesn't cause any problems that I can hear, no noise etc. Got a Sylvania green label from Jeremy. Best tube so far. Hoping he can get another Ken-Rad V231. Some sellers just want crazy money for them. Good luck. If you go with the NOVIB I would love to hear your impressions. Maybe get both and do a comparison???
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Post by ronzo56 on Apr 3, 2015 0:14:23 GMT
Frans,
I have a question about tube Gm for a tube for the Ember. How far off can the sections be? Is 92/102 OK or would I hear a difference between channels? Thanks.
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solderdude
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Post by solderdude on Apr 3, 2015 5:02:56 GMT
That would yield a level difference of 0.9dB between L and R
It's not uncommon for tube halves to differ. I have many tubes here that are over 1dB !
Personally I don't perceive these tubes as leaning to the left or right but YMMV. If it is an expensive tube I would look around a bit longer.
In amplifiers with overall feedback (say MF amps) the difference is negligible and will be 'removed' by the overall feedback.
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Post by ronzo56 on Apr 3, 2015 5:26:30 GMT
Thanks Frans, I will continue to look. Perhaps why the tube has been reduced in price. Is the unit for Gm really a Siemens?
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solderdude
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Post by solderdude on Apr 3, 2015 6:24:24 GMT
Siemens quotes mu but this can be converted to Gm. vrps.org/documents/Gm%20vs%20mu.pdfIME the high Gain tubes are prone to treble roll-off and are much noisier than medium gain tubes. If it says Siemens on the tube chances are it is a Siemens. I have no idea if there are fake Siemens tubes around though.
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Post by ronzo56 on Apr 3, 2015 11:13:35 GMT
I read the whole thing. The data sheets make a little more sense and the non-linearity of tubes as well. Thanks. Guessing a difference of 5 Gm would be much better. No wonder tubes with a 30 or 40 difference sells for $5.00!
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solderdude
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Post by solderdude on Apr 3, 2015 11:41:42 GMT
For the G1217 amps it is easy to calculate the difference in dB (doesn't apply to most other amps)
Divide the two tube halve values (may be Gm or mu). 10LOG the result of the division and multiply the LOG result by 20 and you have the difference in dB.
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z3d
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Post by z3d on Apr 3, 2015 12:01:27 GMT
For the G1217 amps it is easy to calculate the difference in dB (doesn't apply to most other amps) Divide the two tube halve values (may be Gm or mu). 10LOG the result of the division and multiply the LOG result by 20 and you have the difference in dB. Thank you for this useful info Frans
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Post by ronzo56 on Apr 3, 2015 17:49:19 GMT
Thanks Frans for the easy formula. Now I feel a little more informed when looking at tubes.
Edit: just used the formula to calculate tubes I own. Worse was 0.34 dB, best was 0.084 dB.
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Post by musicman on Apr 4, 2015 17:13:39 GMT
Went back to listening to the Ken_Rad tube from Jeremy, and it is going to stay on the amp for the near future. The blacked out tube looks really nice on the Ember and of the other Vt-231's that I have, it is the best sounding of all the tubes I have tried, differences are sometimes subtle, but very noticeable once you swap in a different tube. Lucked out getting this one from Jeremy, asked at just the right time, as he had just got a large shipment of various tubes in. I guess the "force" was with me!
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oldson
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Post by oldson on Apr 4, 2015 19:17:10 GMT
Spot on there Frans, I`m a Watch and Timepiece man, love the engineering which makes up a good movement, not interested in Quartz..LCD etc. I also like Cameras, for the same reason, but have no interest in photography. Mick. i have a couple of cheapish automatics myself. a Bulova and an Oris. have fancied a Breitling for ages. maybe one day
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