Thanks for the clarification on the HPF on the THD measurements, I wondered if there was something like that going on, obviously not got an AP of my own though 
opc, if possible could my pcbs be sent to qusp, saves doubling up on shipping two packages that have final destinations that are only 15mins drive apart. I will pay you for the pcbs when the call for funds is sent and qusp and I will split shipping cost at our end.
When were you looking to sort the remaining headphone amp pcbs left after that GB? I may be interested in a psu pcb if there is one remaining. If you want to sort out these orders first and then see what's left, I totally understand and appreciate the chaos that these threads can create!
As a side note, I just received a message from my wife letting me know that a bal-se pcb size package arrived in our po box from Canada!
Thanks!
opc, if possible could my pcbs be sent to qusp, saves doubling up on shipping two packages that have final destinations that are only 15mins drive apart. I will pay you for the pcbs when the call for funds is sent and qusp and I will split shipping cost at our end.
When were you looking to sort the remaining headphone amp pcbs left after that GB? I may be interested in a psu pcb if there is one remaining. If you want to sort out these orders first and then see what's left, I totally understand and appreciate the chaos that these threads can create!
As a side note, I just received a message from my wife letting me know that a bal-se pcb size package arrived in our po box from Canada!
Thanks!
Hi Guys,
I compiled a list of all the requests so far, and we're at exactly 40 boards.
I was a little ambitious earlier when I said I was going to keep 10 boards, so I'll raise the cap to 44 boards. That means there are 4 left up for grabs, and it's first come first serve.
I'll be sending out payment requests pretty quickly for these, so don't be surprised if you get one tomorrow or Wednesday. I'll ship these with existing orders, and if not, I'll ship them out via lettermail to keep the cost low. Let's say a flat rate of $5 for shipping anywhere for those who don't have outstanding orders.
Cheers,
Owen
I compiled a list of all the requests so far, and we're at exactly 40 boards.
I was a little ambitious earlier when I said I was going to keep 10 boards, so I'll raise the cap to 44 boards. That means there are 4 left up for grabs, and it's first come first serve.
I'll be sending out payment requests pretty quickly for these, so don't be surprised if you get one tomorrow or Wednesday. I'll ship these with existing orders, and if not, I'll ship them out via lettermail to keep the cost low. Let's say a flat rate of $5 for shipping anywhere for those who don't have outstanding orders.
Cheers,
Owen
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Not dumb at all! The front end is an instrumentation style amp and I've placed a single tie-in point where you can choose to populate one resistor or another to turn it into a purely SE input stage with a single op-amp.
If you want to build the SE version, you can omit two of the LME 49990 op-amps and all the associated resistors and just run the input to the +/G terminals on the front of the amp. If you want to run balanced, you need to run the inputs to the +/- inputs labelled as "balanced" and populate all parts on the BOM.
In this case, I would imagine just the SE input would actually measure a little better, but I have yet to verify that.
Regards,
Owen
If you want to build the SE version, you can omit two of the LME 49990 op-amps and all the associated resistors and just run the input to the +/G terminals on the front of the amp. If you want to run balanced, you need to run the inputs to the +/- inputs labelled as "balanced" and populate all parts on the BOM.
In this case, I would imagine just the SE input would actually measure a little better, but I have yet to verify that.
Regards,
Owen
Please forgive my lack of knowledge of electronics as I have taught myself everything I know but I would like to ask a question.
Is this amp operating in Pure class A right to it's rated output?
I understand that an amp can switch between Pure class A into an A/B state after a pre determined output.
Is this what this amp is doing?
I was under the impression that if an amp wanted to be built to the abolute highest stanard it would be a class A design.
thanks for your time.
Is this amp operating in Pure class A right to it's rated output?
I understand that an amp can switch between Pure class A into an A/B state after a pre determined output.
Is this what this amp is doing?
I was under the impression that if an amp wanted to be built to the abolute highest stanard it would be a class A design.
thanks for your time.
depends on the load. TBH there is a lot of the reply to you that is outside the scope of this thread. its an AB amp, but the buffers will operate in class A depending on the load. whether a pure class A design is better or not really is beyond the scope of the thread and if you can show me a class A amplifier that performs better than this design within the power rating, i'll eat my pet goldfish