GB for DC coupled B1 buffer with shunt PSUs - Page 111

Salas · 2nd October 2009, 01:53 AM

Quote:

Originally Posted by grufti

Just making sure that I am not confused: Vgs in your equation refers to Vgs of the K170 following the string [true/false].

On my Mezmerize board the Vgs for the one K170 that I measured is 3.7V. With a 5.7V LED string that amounts to just under 59mA.

The CCS Mosfets Vgs is the oneI refer to. I.e. Rightmost face to face Mosfets.

P.S. It works like a clock with the current you got. You will always check the drop across the R1 you calculated for use. IR1=ICCS=VdropR1/R1. That will be your experimental confirmation if you look to alter the current for any use, or relax a bit some excess if your leds batch is high and/or Mosfets batch Vgs low.

grufti · 2nd October 2009, 02:00 AM

See, I was confused after all. Glad I asked. Thanks.

Salas · 2nd October 2009, 02:06 AM

Did you notice any changes in its performance after enough days BTW? Or different hot touching on Mosfets? Any noises etc?

grufti · 2nd October 2009, 02:18 AM

Very little change. There is maybe, just maybe, even a bit more nuance.

If anything it is noticable in voices where the sense of being right in front of the singer has become absolutely uncanny.

No noises, no temperature drift, no smoke.

The stepped attenuator from Taiwan is pretty amazing for a total of $25 with shipping.

Salas · 2nd October 2009, 02:31 AM

OK then, roughly how many hours we must write on the pdf is that it takes so to settle in your learned opinion? Those must be play hours or just power on is enough?

grufti · 2nd October 2009, 02:52 AM

For me it has been on "non-stop" for about ten days, so 240 hours.

I have turned it off to change from the motorized pot to the stepped attenuator and for swapping out some LEDs, but other than that my DCB1 has been playing music uninterrupted. When I'm not in the room the CDs are on "repeat - play" at minimal volume. When I have a chance to listen I play whatever I fancy at the time and turn up the volume.

The change has not been all that great: 88.9% at one hour - 99.8% at 200 hours, how about that?

Do these machines age like we do? And I know the answer is: fortunately yes! Oxidation, radiation and gravity ultimately win out.

Salas · 2nd October 2009, 03:31 AM

So you did run the most thorough test from all the protos till now. Your contribution was very detailed. I guess we owe you a thanks.

48hours must be ample play time for settling and periodic checks for heat, for some component looking like to go bad, etc. We had no semiconductor failures reported from anybody yet though. Not even brown resistors. That is my experience too but I wanted to hear other opinions first.

MashBill · 2nd October 2009, 04:30 AM

Quote:

Originally Posted by udailey

Prices for LDRs in this group buy will be $32.50. I normally charge 38.42 but in that 38.42 is included shipping and also a $3 donation to DIYaudio. This GB is doing the shipping for me and they are also donating to DIYaudio so my price drops by $6.

Uriah

Uriah,
I want to build a balanced Mesmerize. How much for a balanced set of LDRs?

Thanks,
Bill

udailey · 2nd October 2009, 04:32 AM

$93 after the discounts. Normally 100.22.
Uriah

Ian444 · 2nd October 2009, 05:58 AM

It sure is a nice piece of gear! In my budget system, I use a PC as source, with a DIYparadise USB dac, Lightspeed clone, Tripath TA2020 and FR speakers (Lotus from the Spawn family). I have a long interconnect from the Lightspeed to the Tripath amp, about 5m (15ft). I connected this buffer right after the Lightspeed, and before the long interconnect. It has restored some lost detail, well a lot of detail in fact. It also lifted the volume but I think that is due to better impedance matching as there is no gain as I understand it.

It was sounding a bit edgy at first, but after a few hours it started to come good. The PCB had been powered up approx 15 hours with no music before this though. I used carbon resistors where specified, and low ESR caps, but no boutique parts as yet. The other reason I was interested in this board is that my dac uses +12V and +18V DC supplies, and it appears that this PCB could accomodate that without too much trouble. (I will wait for the GB to try that).

Very happy camper here...this is the best quality I have ever heard out of this system. I thought it was pretty good before, but now it's better

Sure puts a smile on my face.

Thanks again for sharing all your hard work Salas, Tea-bag and CRT. I really appreciate what you are doing.

2nd October 2009, 04:32 AM	#1109
udailey Passive Aggressive diyAudio Member Join Date: Mar 2008	$93 after the discounts. Normally 100.22. Uriah __________________ You can purchase LDRs anytime to build a standard LDR attenuator or to build my new LDR Attenuator "A Lighter Note". Email me. diyldr@gmail.com

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2nd October 2009, 02:00 AM	#1102
grufti diyAudio Member Join Date: Jun 2004 Location: Hillside	See, I was confused after all. Glad I asked. Thanks.

2nd October 2009, 02:06 AM	#1103
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	Did you notice any changes in its performance after enough days BTW? Or different hot touching on Mosfets? Any noises etc?

2nd October 2009, 02:18 AM	#1104
grufti diyAudio Member Join Date: Jun 2004 Location: Hillside	Very little change. There is maybe, just maybe, even a bit more nuance. If anything it is noticable in voices where the sense of being right in front of the singer has become absolutely uncanny. No noises, no temperature drift, no smoke. The stepped attenuator from Taiwan is pretty amazing for a total of $25 with shipping.

2nd October 2009, 02:31 AM	#1105
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	OK then, roughly how many hours we must write on the pdf is that it takes so to settle in your learned opinion? Those must be play hours or just power on is enough?

2nd October 2009, 02:52 AM	#1106
grufti diyAudio Member Join Date: Jun 2004 Location: Hillside	For me it has been on "non-stop" for about ten days, so 240 hours. I have turned it off to change from the motorized pot to the stepped attenuator and for swapping out some LEDs, but other than that my DCB1 has been playing music uninterrupted. When I'm not in the room the CDs are on "repeat - play" at minimal volume. When I have a chance to listen I play whatever I fancy at the time and turn up the volume. The change has not been all that great: 88.9% at one hour - 99.8% at 200 hours, how about that? Do these machines age like we do? And I know the answer is: fortunately yes! Oxidation, radiation and gravity ultimately win out.

2nd October 2009, 03:31 AM	#1107
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	So you did run the most thorough test from all the protos till now. Your contribution was very detailed. I guess we owe you a thanks. 48hours must be ample play time for settling and periodic checks for heat, for some component looking like to go bad, etc. We had no semiconductor failures reported from anybody yet though. Not even brown resistors. That is my experience too but I wanted to hear other opinions first.

2nd October 2009, 05:58 AM	#1110
Ian444 diyAudio Member Join Date: Nov 2008 Location: Brisbane QLD	It sure is a nice piece of gear! In my budget system, I use a PC as source, with a DIYparadise USB dac, Lightspeed clone, Tripath TA2020 and FR speakers (Lotus from the Spawn family). I have a long interconnect from the Lightspeed to the Tripath amp, about 5m (15ft). I connected this buffer right after the Lightspeed, and before the long interconnect. It has restored some lost detail, well a lot of detail in fact. It also lifted the volume but I think that is due to better impedance matching as there is no gain as I understand it. It was sounding a bit edgy at first, but after a few hours it started to come good. The PCB had been powered up approx 15 hours with no music before this though. I used carbon resistors where specified, and low ESR caps, but no boutique parts as yet. The other reason I was interested in this board is that my dac uses +12V and +18V DC supplies, and it appears that this PCB could accomodate that without too much trouble. (I will wait for the GB to try that). Very happy camper here...this is the best quality I have ever heard out of this system. I thought it was pretty good before, but now it's better Sure puts a smile on my face. Thanks again for sharing all your hard work Salas, Tea-bag and CRT. I really appreciate what you are doing.

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