Simple High Performance DC Coupled Class A HPA with sub PPM THD

[yourownbuzz]

for people who are getting ready to order parts - came across another supplier while looking up parts for another project - arrow electronics. they do free shipping with no threshold worldwide, and seem to be cheaper on some parts.

www.arrow.com

 

[xrk971]

Hi all, I have been having some major medical drama around here - in and out of surgery , in and out of the Emergency room many times , in and out of surgery Again --- so I missed the the buy . . . so I was wondering if anyone has any extra Pcb's they would be willing to part with? I would be very grateful - Thank you, Dean

Sorry about your health issues. Hope you are feeling better. I have more boards, just send me a PM with your PayPal address, number of board you need and country to ship to. Cost is $28ea and shipping is $5 in US, $12 Can, $15 everywhere else.

 

[oxothuk]

I wonder how LDOVR.com manages to make the TPS7A3301 programmable? The datasheet shows that you need to use 2 resistors according to table 2 according to relation:
R1=R2x(Vout/Vref-1).

Maybe it's a different LDO chip? But looks like the TPS7A3301:
TPS7A3301 Ultra Low Noise LDO Voltage Regulator

it's Magic, but can be sure that it is original TPS7A3301

 

[xrk971]

it's Magic, but can be sure that it is original TPS7A3301

Hi Oxothuk (Alexey?),
Thanks for chiming in - can you make these with a small pot built in? You make top notch stuff with genuine quality parts, I totally agree.
Regards,
X

 

[oxothuk]

i don't like the idea to use variable resistors within ref voltage circuit for low noise application

 

[xrk971]

In that case some micro dip switches to set voltages quickly might be nice.

 

[avtech]

...I have more boards, just send me a PM...

I was trying to get hold of some boards back in July. Do you have any extra available at all?

Cheers

 

[xrk971]

I was trying to get hold of some boards back in July. Do you have any extra available at all?

Cheers

Yes, how many do you need?

 

[avtech]

Yes, how many do you need?

PM sent thanks!

 

[xrk971]

Hi Avtech,
Your board will go out tomorrow to Oz.
Thanks,
X

 

[avtech]

Hi Avtech,
Your board will go out tomorrow to Oz.
Thanks,
X

Boards received, thanks!

 

[xrk971]

Thanks for letting me know - did that really take a month to get to OZ?

 

[avtech]

Thanks for letting me know - did that really take a month to get to OZ?

I was interstate for a couple of weeks, so I think it only took about a fortnight in the end.

 

[xrk971]

Another option for a power supply for this amp if one wanted to use a linear supply would be the new Mark Johnson/Gtose cap multiplier. Beautiful layout by Prasi. This cap mx board has advantage that there is a pot to adjust dropout voltage from 1.3v and up to about 2-3v. So one could set perfectly balanced upper and lower rails at +/-18v.

https://www.diyaudio.com/forums/pow...sy-capacitance-multiplier-55.html#post5566935

 

[yourownbuzz]

from a quick look at the thread it looks like it needs both + & - inputs....or does this board also split single rail to dual rail?
it does look pretty impressive and imposing though

 

[xrk971]

That’s a dual rail cap Mx board. Prasi just made me a smaller layout of a version of this board using SMT components and TO220 BJTs and an on board rectifier bridge to make lower current (1A and under) dual rail output.

 

[ernesternest]

Nice and small, yet great ;-)

 

[yourownbuzz]

finally ordered the parts for the amp ! got the meanwell power converter instead, for anyone thinking about getting it - its much larger and no way of fitting on the pcb

X:
with heatsinking of the mosfets, would the same ones you used for the power regs be fine? or does it need something beefier ? (I seem to remember you hooking it up to a pretty big heatsink with CPU fans...or was that another thread?)
heatsink on power regs as in this post - https://www.diyaudio.com/forums/gro...led-class-hpa-sub-ppm-thd-24.html#post5534747

 

[xrk971]

That was another thread. This amp works fine if you simply use the baseplate of the amp as a heatsink. 18v x 125mA is about 2w per MOSFET so 8w total.

 

[Harry3]

Input resistors

Hi
What is the purpose of having a 2K2 resistor and a 100R resistor at the input?
Can I short one out eg the 100 R or am I missing something?
I’m asking because I’m trying to cut down the number of components on the input side.

PS do you need a regulator with the cap multiplier above?