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#585
Andrew,

While I agree with your suggestion to conform to convention where practical, the colours are just what is provided on the Antek 50VA transformers - AS-0518 - 50VA 18V Transformer - AnTek Products Corp

To join different colour wires to the transformer ... seems impractical and given that it is going to be obvious that the wire is from the transformer and to the AC inlet of the amplifier PCB it is not really something that I think should be changed.

@momomo, I'd keep the ordering consistent, blue, green, blue, green ... the polarity of the diodes and caps is reversed so reversing the AC wiring as well ... defeats that logic. At a quick guess the polarity of the AC outputs shouldn't matter a great deal, it's AC ... but it is nice to be consistent.

Chris
 
#589
Kastor L said:
Hi! I've had my eye on this amplifier for a while.

Just a quick query, is there an alternative to the LME49600 buffers in this project? I.e. do some users prefer to use a different IC? Would it be theoretically possible to use more LME49990 instead?

Thanks in advance.
Click to expand...

There is the LME49610 alternative. No reports of anyone using anything else as far as I can see.

You can't use more LME49990 on this PCB so it's theoretically not possible on that basis I suppose.


Build the provided BOM on these PCBs and enjoy is the normal recipe for success 🙂
 
#590
Alright, I'll follow the usual BOM, I'm just curious if there's any alternative routes or experiments, especially in the buffer section.

For example, I wonder what would happen if you put a different buffer like LT1010 or another pair of LME49990 where the LME49600 is, or if we can simply bypass the LME49600 and listen buffer-less.

The reason would be purity, like "a pure LME49990 circuit", without the subtle differences in electron shifts, circuit type or slew-rate induced distortion etc. the LME49600 theoretically causes hehe 🙂.

I respect the design as it is, however if the only difference in buffer-less or 4x LME49990 is lower mA output then I would like to try.
 
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#592
Kastor L said:
Alright, I'll follow the usual BOM, I'm just curious if there's any alternative routes or experiments, especially in the buffer section.

For example, I wonder what would happen if you put a different buffer like LT1010 or another pair of LME49990 where the LME49600 is, or if we can simply bypass the LME49600 and listen buffer-less.

The reason would be purity, like "a pure LME49990 circuit", without the subtle differences in electron shifts, circuit type or slew-rate induced distortion etc. the LME49600 theoretically causes hehe 🙂.

I respect the design as it is, however if the only difference in buffer-less or 4x LME49990 is lower mA output then I would like to try.
Click to expand...
If you bypass the buffer it wouldn't be "the Wire" any longer😀. Take a look here AGDR had an idea about using paralleled lme49990s for a headphone amp.
 
#597
I finally found solution to DC transient during turning off described by me and @BuildMeSomething at page 45.
It was caused by LED indicating power. Even such small load at only one power rail was causing discharging capacitors asymmetrically and causing DC transient at powering off. After removing that LED transient to not exceed 50mV, down from 1.9V spike before.
Anyway power LED is very handy and now i wonder how to connect it without problems.
A better solution would be connecting second LED balancing load to negative rail or maybe just connecting LED straight to transformer by simple bridge?
 
#598
Hi Gents,

juswyq:

Boards will be shipping out today for anyone who placed an order over the last few weeks.

BamboszeK:

Glad to hear you tracked down the source of the transient! I suppose you could always wire the LED across the + and - supplies with a larger resistor to cope with the higher voltage drop. This would at least load the two supplies symmetrically.

Regards,
Owen
 
#599
I often connect an indicating LED across the +ve to -ve supply rails.

To get a better idea of low voltage, I use a Zener somewhere between half supply voltage and three/quarters of supply voltage.

This turns the LED off fairly quickly if the supply voltage is low for some unknown reason.
 
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