BPA300 Round 2

[peranders]

Rhys, you have been online today and most likely read the thread you are involved in and I'm pretty sure you have subscriptions of this thread. Send me an email, SMS or call me. We must have info about your actions.

[peranders]

Originally Posted by logical

how much for the Dale resistors ? shipping would be very cheap, as much as for a simple letter.

The price is approx. one dollar each and the shipping cost 26 SEK world wide.

[peranders]

SMD kit per pcb will be 120 SEK plus 26 SEK shipping for maybe 10 kits. The parts are pretty expensive in small quantities but if you want some help, I can help you. I'm going to order parts from Farnell so can order those too. I will order this weekend so hurry up if you want these parts.

[peranders]

Originally Posted by peranders

14 BPA150 boards are missing. I wonder if I should order more boards when I'll order my rectifier boards? I have OK from alexw88 to use his gerber files. Price could be 10 USD, red boards, gold pads, print on both sides, 70 um, 2 oz. copper. If there is an interest of round 3 of this, let me know. I will also have DRV134 boards. But this is only about pcb's and possibly the DRV134 IC.

I have ordered some PA150 pcb's, 70 SEK (approx. 10 USD) a piece and a few DRV134 pcb's (my design), 56 SEK approx. 8 USD. The DRV134 boards aren't debugged yet so they may need patches. Send me a message if your are interested.

[shmulik]

I though of allowing adding balanced input to the amplifier, merely because my line stage has balanced output only. I thought of 2 options:
1) using the INA137 counterpart of the DRV134. switching between single ended and balanced via a relay and switch on the back panel. the output of the 137 is the input of the 134
2) using a differential line driver (what chip? I have no SMD PCB creating ability so DIP is preferred unless someone will produce such board for me). do I need a pulldown resistor at the input of each PA150 until switch is made (see below)?

option 1 is modular and easier to implement with my humble means on a strip board but it has a longer audio path compared to the second option which requires a switching of 2 lines compared to only one in option 1. assuming I will switch only with power off, I still need to consider how to handle the time it takes to switch in both options, so no input is left on air.

please comment and share your ideas.

[Lucas_G]

Originally Posted by peranders

SMD kit per pcb will be 120 SEK plus 26 SEK shipping for maybe 10 kits. The parts are pretty expensive in small quantities but if you want some help, I can help you. I'm going to order parts from Farnell so can order those too. I will order this weekend so hurry up if you want these parts.

That's great!
Since Rhys didn't deliver the SMD resistors (for which I paid him), I would like to join in your collect order. Please count me in for 2 kits SMD parts.
Thanks for all the great work, Per Anders!

Lucas

[peranders]

Originally Posted by shmulik

I though of allowing adding balanced input to the amplifier, merely because my line stage has balanced output only. I thought of 2 options:
1) using the INA137 counterpart of the DRV134. switching between single ended and balanced via a relay and switch on the back panel. the output of the 137 is the input of the 134
2) using a differential line driver (what chip? I have no SMD PCB creating ability so DIP is preferred unless someone will produce such board for me). do I need a pulldown resistor at the input of each PA150 until switch is made (see below)?

option 1 is modular and easier to implement with my humble means on a strip board but it has a longer audio path compared to the second option which requires a switching of 2 lines compared to only one in option 1. assuming I will switch only with power off, I still need to consider how to handle the time it takes to switch in both options, so no input is left on air.

please comment and share your ideas.

You mean you will have the option for balanced or unbalanced in and balanced out? Could you draw a sketch with input signals, output, and functions for switching mode? Just draw it on paper and take a photo. You could email it to me if you want. I might consider to design such board.

[shmulik]

P-A,
sent you mail with sketches . has it went through your electronic fortifications ?

[peranders]

I have got it. Just wondering, what is your need for this pcb? Do you want an amp with dual inputs?

[shmulik]

my current linestage has balanced output only (actually it is a modified Behringer dcx2496). one can use this balanced output as it is with a single ended power amps (like I do today), but wire to single phase and then expand to 2 phases (by using the drv) seems awkwards to me. it is more natural to just buffer the differential input with something like the opa1632. however, balanced-input-only power amp is a kind of intentional disability if you ever want to take it to other systems.
taking the above into account, I plan to place both RCA and XLR sockets on the back of the amp and switch between the two per need. I don't mean to do the switching online, though, e.g. for comparison purposes.