Helder MKII TA2020 Amp PSU Wiring

Obe1 · 5th March 2010, 05:17 PM

Hello All,

I just purchased one of Arjen Helder's MKII TA2020 amplifiers and the associated DC power supply. Arjen includes a SPST power switch with an internal LED. I assume this switch is to control DC power into the amplifier board, so I think it makes sense to add my own power switch to the AC mains as well (ahead of the PSU). In fact, I'm not sure why I need Arjen's power switch at all, if I provide my own power switch on the AC mains.

The attached sketch is my attempt to guess how the power circuit should look. Any feedback or suggestions on how best to wire-up one of Arjen's amplifiers is most welcome.

Best regards,

Obe1

onis_uk · 6th March 2010, 03:38 PM

looks ok to me !

audi0 · 6th March 2010, 05:49 PM

Don't forget that you will need a resistor on the LED! The value varies a bit depending on the LED colour, forward current and typical voltage.
Resistor value = source voltage - LED operating voltage / by the LED forward current.
eg. 12 - 2.1 = 9.9 / by 30 = .33 or 330 Ohms

Obe1 · 6th March 2010, 05:52 PM

Hi onis,

It took several days, but I just got an email back from Arjen that my connection digram would work. Unfortunatly, he didn't offer any thoughts on how to make it better. I guess I'll just have to wait for the goods to arrive from China and then play around a bit.

Thanks and take care,

Obe1

Obe1 · 6th March 2010, 05:55 PM

Hello Audi0,

Yes. That's a good point. I'll run some test once it arrives, as I've seen some of these illuminated switches have their own internal dropping resistor.

Thanks,

Obe1

audi0 · 6th March 2010, 06:04 PM

Yeah, sorry I didn't see the illuminated switch in the picture

Why would you want to switch it twice? I would think that the AC switch would be sufficient

Obe1 · 6th March 2010, 06:27 PM

Hi audi0,

Well, if you read my original post, I had the exact same question. On one hand just switching the AC on & off seems adequate, yet Arjen went to the trouble of including a DC switch, so maybe it has some value. Perhaps it helps minimize "thumping" your speakers during power ups or downs.

Thanks,

Obe1

audi0 · 6th March 2010, 06:37 PM

Some of us run our amps off of batteries, on one of my systems I use a 12v 7.2Ah SLA supply , the switch could be employed in such a case.
The SMPS could be left running and you could switch the DC?

Obe1 · 16th March 2010, 03:07 PM

The amplifier and power supply I ordered from Arjen (just 2 weeks ago) arrived yesterday. I ran some tests on the illuminated rocker switch and discovered that the lamp is a neon bulb and not an LED as illustrated in my sketch in post #1. As such, this lamp will need a lot more than 12Vdc to illuminate and so this switch is better suited for control & indication of AC mains power.

gychang · 7th June 2011, 03:22 PM

Quote:

Originally Posted by Obe1

The amplifier and power supply I ordered from Arjen (just 2 weeks ago) arrived yesterday. I ran some tests on the illuminated rocker switch and discovered that the lamp is a neon bulb and not an LED as illustrated in my sketch in post #1. As such, this lamp will need a lot more than 12Vdc to illuminate and so this switch is better suited for control & indication of AC mains power.

realize this is an old thread, I have the same board and considering it putting it all together.

How does it sound?, any difficulties in getting it all connected?, will likely add pot/volume and 2 way RCA input selector.

6th March 2010, 05:49 PM	#3
audi0 diyAudio Member Join Date: May 2009 Location: 37.34 degrees South Blog Entries: 5	resistor Don't forget that you will need a resistor on the LED! The value varies a bit depending on the LED colour, forward current and typical voltage. Resistor value = source voltage - LED operating voltage / by the LED forward current. eg. 12 - 2.1 = 9.9 / by 30 = .33 or 330 Ohms

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6th March 2010, 03:38 PM	#2
onis_uk diyAudio Member Join Date: Jul 2004 Location: uk	looks ok to me !

6th March 2010, 05:52 PM	#4
Obe1 diyAudio Member Join Date: Jan 2010 Location: Stumptown	Hi onis, It took several days, but I just got an email back from Arjen that my connection digram would work. Unfortunatly, he didn't offer any thoughts on how to make it better. I guess I'll just have to wait for the goods to arrive from China and then play around a bit. Thanks and take care, Obe1

6th March 2010, 05:55 PM	#5
Obe1 diyAudio Member Join Date: Jan 2010 Location: Stumptown	Hello Audi0, Yes. That's a good point. I'll run some test once it arrives, as I've seen some of these illuminated switches have their own internal dropping resistor. Thanks, Obe1

6th March 2010, 06:04 PM	#6
audi0 diyAudio Member Join Date: May 2009 Location: 37.34 degrees South Blog Entries: 5	Yeah, sorry I didn't see the illuminated switch in the picture Why would you want to switch it twice? I would think that the AC switch would be sufficient

6th March 2010, 06:27 PM	#7
Obe1 diyAudio Member Join Date: Jan 2010 Location: Stumptown	Hi audi0, Well, if you read my original post, I had the exact same question. On one hand just switching the AC on & off seems adequate, yet Arjen went to the trouble of including a DC switch, so maybe it has some value. Perhaps it helps minimize "thumping" your speakers during power ups or downs. Thanks, Obe1

6th March 2010, 06:37 PM	#8
audi0 diyAudio Member Join Date: May 2009 Location: 37.34 degrees South Blog Entries: 5	Some of us run our amps off of batteries, on one of my systems I use a 12v 7.2Ah SLA supply , the switch could be employed in such a case. The SMPS could be left running and you could switch the DC?

16th March 2010, 03:07 PM	#9
Obe1 diyAudio Member Join Date: Jan 2010 Location: Stumptown	The amplifier and power supply I ordered from Arjen (just 2 weeks ago) arrived yesterday. I ran some tests on the illuminated rocker switch and discovered that the lamp is a neon bulb and not an LED as illustrated in my sketch in post #1. As such, this lamp will need a lot more than 12Vdc to illuminate and so this switch is better suited for control & indication of AC mains power.

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