My B1 Nutube PCB and Nutube arrived today. Can't wait to get soldering and listening started.
I want to thank Mr. Pass for his generous donation of PCBs and FETs to the community. Another big thank you goes Puggie for organizing the tubes and qwertyl for much of his work distributing everything around Europe!
Cheers,
Fabian
I want to thank Mr. Pass for his generous donation of PCBs and FETs to the community. Another big thank you goes Puggie for organizing the tubes and qwertyl for much of his work distributing everything around Europe!
Cheers,
Fabian
very quiet
Congratulations Cjfrbw
Do You tested voltages at T1 to T8 points from article ?
What about music ?
Congratulations Cjfrbw
NuTube looks good to go. I still have to connect signal inputs and outputs/volume control and finesse the board on it's altar. It's still only part way there. Maybe I will get it done tonite and tested.
How much is Your filaments voltages at T5, T6 ?
Me too I need back on the work bench
Have a good timeCongratulations Cjfrbw
Do You tested voltages at T1 to T8 points from article ?
What about music ?
T1 is 24V DC, very close.
T3 is 23V DC, very close to NP's article
T4 is 9.16V DC, pretty close to NP's article recommendation.
As stated, T7 and T8 both bias easily without warm up to the 9-11 V DC range.
And T5,T6 ?How much is Your filaments voltages at T5, T6 ?
Me too I need back on the work bench
Without much warm up, T5 and T6 measure about .62 V DC to .63 V DC without adjustments. It looks like everything is on spec for the NuTube, at least.
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Here's a mouser cart:
Mouser Electronics Inc. Nederland
Beware the extra 10uF caps and I added a few 100 Ohm resistors which were replaced by 6L6 for 220 Ohm? Probably not needed..
Mouser Electronics Inc. Nederland
Beware the extra 10uF caps and I added a few 100 Ohm resistors which were replaced by 6L6 for 220 Ohm? Probably not needed..
From First Watt article resistors reference are SFR25 made by Vishay BC
https://www.mouser.fr/datasheet/2/427/sfr16s25-239894.pdf
https://www.mouser.fr/datasheet/2/427/sfr16s25-239894.pdf
I believe RN55 series resistors are fine, and those are mil-spec'ed ratings;
CMF55 is the industrial counterpart.
According to http://www.vishay.com/docs/31018/cmfind.pdf
the mil-spec'ed and industrial versions are the same except for markings.
And CMF55 is rated at 0.25 to 0.5W depending on ambient temperature:
http://www.vishay.com/docs/31018/cmfind.pdf
CMF55 is the industrial counterpart.
According to http://www.vishay.com/docs/31018/cmfind.pdf
the mil-spec'ed and industrial versions are the same except for markings.
And CMF55 is rated at 0.25 to 0.5W depending on ambient temperature:
http://www.vishay.com/docs/31018/cmfind.pdf
I just hooked up the Xmas B1 Korg to the analog LX mini crossover and had a listen. Some time ago, I found the analog crossover to be a big improvement over the miniDSP crossover. The B1 Korg is an even bigger improvement to the LX mini loudspeaker sound. I'm using high quality 100W/per channel class D amplifiers and the B1 Korg is a perfect compliment. It's magic. Highly recommended.
Oh, and after much messing around with a precision sine wave generator connected to an Eiderol outboard USB A to D on a computer running REW software to measure distortion, I found the measured levels so sensitive to signal level through the B1 Korg as well as to signal level settings of the a/d/computer that I just ended up setting the plates to 9.4 VDC and calling it a day. The preamp sounds great at that setting and I suspect the exact plate voltage is not so critical or Papa would have put multi turn pots on the board.
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Vishay BC SFR25 on actual Mouser page are 1/4 watts but CMF55 , RN55 are not..
Yes, but the RN55 are severely underrated for military and aerospace and work just fine with light loads they see in the B1 Korg.