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7-pin miniature tubes for audio?
7-pin miniature tubes for audio?
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Old 3rd March 2007, 07:48 PM   #21
DSP_Geek is offline DSP_Geek  Canada
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Quote:
Originally posted by Klimon
They claim "10-20KHz +0/-2dB"; is this anywhere near possible with that miniature size opts, even with truckloads of gNFB??
Sure, it only has 1 watt output per channel. Look at Hammond type 125ASE in http://www.hammondmfg.com/125SE.htm - at 3 watts it's not much bigger than the transformers shown in the picture.
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Old 3rd March 2007, 09:54 PM   #22
aletheian is offline aletheian  United States
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Quote:
Originally posted by Tom Bavis
Ray had an an article on the 6AU6, and I posted it on my site: http://www.audiophool.cjb.net/Misc/6...ed%20plate.pdf

HEY THAT"S HET ONE! Good catch!
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Old 3rd March 2007, 10:06 PM   #23
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7-pin miniature tubes for audio?
EC900 is mentioned
PC900 must be even cheaper everywhere
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Old 4th March 2007, 09:26 AM   #24
ray_moth is offline ray_moth  Indonesia
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The caveats for running a 6AU6 as a triode with grounded plate and grid 2 acting as the sole anode are:

1. Don't exceed the maximum grid 2 dissipation of 650 mw, and

2. Only use it with small signals, e.g. in a preamp, to avoid poor linearity.

I used it successfully like this in a preamp stage following a James-type tone stack, which has an attenuation factor of 12dB, thus the signal was very small.
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Old 4th March 2007, 09:35 AM   #25
poynton is offline poynton  United Kingdom
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Quote:
Originally posted by Runco990
Speaking of small tubes, has anyone looked at this: http://www.impamp.com/

Any idea what tubes are used. ?

I think 6021 from the video but for output??

Wire-ended pentodes ? [type numbers ?]

Andy
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Old 4th March 2007, 10:03 AM   #26
Eusebius is offline Eusebius  United Kingdom
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I'll recommend the 3A5 - cheapest good sounding DHT, and a double at that. I bought 100 really cheap - they're slightly bright but very detailed and have that genuine DHT sound. You need a good filament supply as always with DHTs. I use them in diff pairs to reduce mcrophonics, and put a couple of cheap plumbers rubber rings on each. Definitely one to try out for peanuts, since the really good DHTs are getting scarce and going up in price.
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Old 4th March 2007, 02:50 PM   #27
Runco990 is offline Runco990  United States
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Quote:
Originally posted by poynton


Any idea what tubes are used. ?

I think 6021 from the video but for output??

Wire-ended pentodes ? [type numbers ?]

Andy
It's a philips 6021 dual triode tube. If you click on the main pic, you'll get to a few videos that explain the amp and the tubes.

Marc
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Old 4th March 2007, 03:43 PM   #28
andrew_whitham is offline andrew_whitham  United Kingdom
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the problem with this thread is that you worry may be you havent got enough before the prices go north...

or is that me?

letting the cat out what about the ec91? this will, at the moment, be my input stage. Unless its the 6AT6

and If I might be a little bold I didnt think the 6AU7 was that special from the plate curves. Am I missing something? - The triode curves are the first place I look no-matter-what If they arent evenly spaced then And it didn't make my list.

should we (I) consider other factors? but for me if there's not good intrinsic linearity then consider something else. this is why the *sn7 are so well regarded, and the 300B (OK I have to admit it curves nice...)

Andy
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Old 4th March 2007, 06:07 PM   #29
aletheian is offline aletheian  United States
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Quote:
Originally posted by poynton


Any idea what tubes are used. ?

I think 6021 from the video but for output??

Wire-ended pentodes ? [type numbers ?]

Andy
I think there is a lengthy thread on this board somewhere... and the inventor even pops his head in to add some info.
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Old 4th March 2007, 10:06 PM   #30
Klimon is offline Klimon  Belgium
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Quote:
Sure, it only has 1 watt output per channel. Look at Hammond type 125ASE in http://www.hammondmfg.com/125SE.htm - at 3 watts it's not much bigger than the transformers shown in the picture.
True but the hammond is only spec'd for 100hz -1db

Simon
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