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#16

Posted: Wed Jan 14, 2009 9:40 pm
by Andrew
Blummin 'eck. Sure beats my ideas of an Aikido using 6H30s, well at least it does on size.

Reminiscent of Stephen's (izzywizzy) 813 push pull amp I believe you had to walk around it to work on it :shock:

-- Andrew

#17

Posted: Wed Jan 14, 2009 10:22 pm
by Nick
Interesting thing I have found tonight, connecting headphones the big problem was noise (white) not hum as I expected, and the source of noise seems to be the DC heater supply for the first 211. I have added a hum pot which lets me null it a bit, but it will need a better solution. So I need a heater supply that sounds good, and is quieter than a tent labs supply. (and does 10v @ 3.25A)

#18

Posted: Wed Jan 14, 2009 10:34 pm
by Andrew
So its broadband noise produced by the regs in the tent supply?

#19

Posted: Wed Jan 14, 2009 10:48 pm
by simon
Probably not related at all but I found when I was playing around with the Aikido headphone amp that listening with headphones I was a aware of all sorts of sound issues that I don't think I would have been with an amp used through speakers. There seems to be something very "dialled in" about headphones.

#20

Posted: Wed Jan 14, 2009 11:32 pm
by Nick
Andrew wrote:So its broadband noise produced by the regs in the tent supply?
I can only assume so, it nulls in the same way as AC would.

#21

Posted: Wed Jan 14, 2009 11:41 pm
by Andrew
Have you 'scoped it? Will it filter out with a low pass filter? I tried a cap multiiplier of the LCR and I think it has improved things but that might screw up the Tent modules, I haven't studied the circuit on those things.

Just random late night thoughts....

-- Andrew

#22

Posted: Wed Jan 14, 2009 11:43 pm
by Nick
Andrew wrote:Have you 'scoped it? Will it filter out with a low pass filter? I tried a cap multiiplier of the LCR and I think it has improved things but that might screw up the Tent modules, I haven't studied the circuit on those things.

Just random late night thoughts....

-- Andrew
I have been having similar thoughts. I was wondering about a choke or too as well.

#23

Posted: Wed Jan 14, 2009 11:49 pm
by Andrew
Did you mean a CLC supply and not use the Tent modules, or a ferrites to knock out the HF? Both came to my mind.

-- Andrew

#24

Posted: Thu Jan 15, 2009 7:51 am
by Nick
Hmm, both also. I was also thinking aboiut a seres VR followed by a emmiter follower, then a choke in each lead.

#25

Posted: Thu Jan 15, 2009 8:16 am
by andrew Ivimey
Of course VR valves have their own tuppence of noise too, but tameable, surely!

#26

Posted: Thu Jan 15, 2009 9:24 am
by Andrew
andrew Ivimey wrote:Of course VR valves have their own tuppence of noise too, but tameable, surely!
I think Nick meant a series reg LM317 type thingy, but I'm not certain.

-- Andrew

#27

Posted: Thu Jan 15, 2009 9:25 am
by Nick
My mistake I meand VR = voltage reg, I was thinking of a three pin reg, then the VBE to reduce noise.

#28

Posted: Thu Jan 15, 2009 9:29 am
by andrew Ivimey
yeah that might do it! I just like the flashy glow! - nb, I too have a pair of 866s glowing nicely in the wings!