Patchwork Reloaded: Circuit Optimization and Board Layout. - Page 63

MJL21193 · 03:17 AM

Looks good to me!

454Casull · 17th October 2009, 03:45 AM

Hm, forgot to put the index numbers back in, and the note about the faston header is cut off

version 1.01 attached

destroyer X · 17th October 2009, 12:47 PM

YouTube - Audio amplifier test - Dx TriAmp

If you dislike that, then just let me know and i will remove your codename (Mjl21193) from the video.

I was saying good things about your amplifier.... i was just fair..do not need to thank me because of that.

- "To Ceasar what belongs to Ceasar..to the Lions what belongs to Lions"

Yeah... the recording resulted awfull (will make another one)...maybe you will dislike your name there because of that.

ahahahahah!

regards,

Carlos

MJL21193 · 17th October 2009, 05:22 PM

No problem Carlos.
You are hooked on the fun stuff now - a great reason to build more amps

454Casull · 18th October 2009, 07:09 AM

Do you have any specs/graphs for this amp besides harmonic distortion and PSRR? What's the max power at 8/4/2 ohms? Maximum rail voltage? Maximum current? How close can the output voltage swing toward the rail voltage?

MJL21193 · 02:46 PM

There are some full power tests further back in this thread (I think). It's in excess of 140 watts into 8 ohms. Running it on a 4 ohm load is fine but make sure there is a good heatsink. 2 ohms is NOT recommended.

The max rail voltage for this (indeed, the voltage it was designed for) is +/-56VDC. To use a lower rail voltage would require changing the frontend cascode voltage divider (specifically R4), R11 to adjust current thru the VAS and R27 to adjust the current thru the frontend. Gain would need to be adjusted also - R26.

454Casull · 18th October 2009, 07:56 PM

What happens when you hook up a 2 ohm load?

ostripper · 18th October 2009, 09:45 PM

[QUOTE]What happens when you hook up a 2 ohm load?/QUOTE]

Seriously , if the amp is properly fused , you will just blow them , not the outputs. (I did this).
OS

MJL21193 · 18th October 2009, 10:02 PM

The current capacity of the amp would be exceeded and the outputs would fail.
Is a 2 ohm load a serious option? This was initially designed for an eight ohm load but will do 4 ohms fine. For a 2 ohm load, rail voltage would need to be drastically reduced.

EDIT: Sorry OS, we posted together.

454Casull · 10:46 PM

So what is the current capacity, then? Is there no overcurrent protection?

The rails will be fused for each channel, yes.

EDIT: I assume that fast-blow fuses are preferred. What value should they be?

17th October 2009, 03:12 AM	#621
MJL21193 Account disabled at member's request Join Date: Mar 2007	Looks good to me! patchwork_bom.pdf Last edited by MJL21193; 17th October 2009 at 03:17 AM.

17th October 2009, 12:47 PM	#623
destroyer X diyAudio Member Join Date: Feb 2004 Location: Recife - Brasil Northeast	I have mentioned your name into my "BiAmp release" video YouTube - Audio amplifier test - Dx TriAmp If you dislike that, then just let me know and i will remove your codename (Mjl21193) from the video. I was saying good things about your amplifier.... i was just fair..do not need to thank me because of that. - "To Ceasar what belongs to Ceasar..to the Lions what belongs to Lions" Yeah... the recording resulted awfull (will make another one)...maybe you will dislike your name there because of that. ahahahahah! regards, Carlos __________________ Try to build an amplifier folks ... it is pure adrenaline!.. when not work first time, then becomes a nice challenge...and we usually overcome the trouble... and we feel very well to be mastering the machine.

18th October 2009, 07:09 AM	#625
454Casull diyAudio Member Join Date: Jan 2004 Location: Toronto, ON, Canada	Do you have any specs/graphs for this amp besides harmonic distortion and PSRR? What's the max power at 8/4/2 ohms? Maximum rail voltage? Maximum current? How close can the output voltage swing toward the rail voltage? __________________ Building a 2.1 system out of a 3/4"x4'x8' sheet

18th October 2009, 02:35 PM	#626
MJL21193 Account disabled at member's request Join Date: Mar 2007	There are some full power tests further back in this thread (I think). It's in excess of 140 watts into 8 ohms. Running it on a 4 ohm load is fine but make sure there is a good heatsink. 2 ohms is NOT recommended. The max rail voltage for this (indeed, the voltage it was designed for) is +/-56VDC. To use a lower rail voltage would require changing the frontend cascode voltage divider (specifically R4), R11 to adjust current thru the VAS and R27 to adjust the current thru the frontend. Gain would need to be adjusted also - R26. Last edited by MJL21193; 18th October 2009 at 02:46 PM.

18th October 2009, 07:56 PM	#627
454Casull diyAudio Member Join Date: Jan 2004 Location: Toronto, ON, Canada	What happens when you hook up a 2 ohm load? __________________ Building a 2.1 system out of a 3/4"x4'x8' sheet


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17th October 2009, 05:22 PM	#624
MJL21193 Account disabled at member's request Join Date: Mar 2007	No problem Carlos. You are hooked on the fun stuff now - a great reason to build more amps

18th October 2009, 09:45 PM	#628
ostripper diyAudio Member Join Date: May 2008 Location: Albany , NY (smallbany)	[QUOTE]What happens when you hook up a 2 ohm load?/QUOTE] Seriously , if the amp is properly fused , you will just blow them , not the outputs. (I did this). OS

18th October 2009, 10:02 PM	#629
MJL21193 Account disabled at member's request Join Date: Mar 2007	The current capacity of the amp would be exceeded and the outputs would fail. Is a 2 ohm load a serious option? This was initially designed for an eight ohm load but will do 4 ohms fine. For a 2 ohm load, rail voltage would need to be drastically reduced. EDIT: Sorry OS, we posted together.

18th October 2009, 10:27 PM	#630
454Casull diyAudio Member Join Date: Jan 2004 Location: Toronto, ON, Canada	So what is the current capacity, then? Is there no overcurrent protection? The rails will be fused for each channel, yes. EDIT: I assume that fast-blow fuses are preferred. What value should they be? __________________ Building a 2.1 system out of a 3/4"x4'x8' sheet Last edited by 454Casull; 18th October 2009 at 10:46 PM.

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