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.
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.
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.
balaced input
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.
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.
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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
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.
I have got it. Just wondering, what is your need for this pcb? Do you want an amp with dual inputs?
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.
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.
Stuff Showed Up
Just wanted to say my stuff showed up....🙂 I have yet to do a full inventory, but it looks like I'm missing (in addition to the 1 PA150 PCB) all 6 LM3886T's, and the 6 Dale resistors ATM.
Just wanted to say my stuff showed up....🙂 I have yet to do a full inventory, but it looks like I'm missing (in addition to the 1 PA150 PCB) all 6 LM3886T's, and the 6 Dale resistors ATM.
Sorry, this seems to be my mistake. I will correct this when I order parts from Farnell. The missing PA150 might turn up but if not I will have red ones in two weeks.
not exactly. it does not have the nice feature of being immune to passive linestage. it does simplify things, though. I've seem people manage soldering so-8 chips to strip boards and chip converter pcbs (so-8 to dip), so I think I'll give it a try even if P-A will decide it is not worthwhile to plan a dedicated board on behalf of the less knowledgeable.
It seems that you are alone about this but I think you could use an OPA1632 and some circuits for shorting one input when you want to use unbalanced signals.
Hi i just received 4 PA150 boards. Thank you very much PA. I am waiting for the DRV134 boards 🙂
PA,
I have several bare transformer cores here and was wondering if you had a sketch of what the windings for unbalanced to balanced connections look like. There are many generic type layouts on the web. I just need the simple primary to secondary tap arrangements. Transformer winding info is like hens teeth. Very hard to find in simple form. If I use the proper gauge wire these cores should be good for at least 100khz
Thanks for the fabulous job you have done with this group buy. Kudos.
Post a sketch of your drv pcb when you get time. The only problem I ever had with the drv was buzzing from the wire layout. It was very hard to get rid of.
Anyone finish there bpa300 projects yet?
Tad
I have several bare transformer cores here and was wondering if you had a sketch of what the windings for unbalanced to balanced connections look like. There are many generic type layouts on the web. I just need the simple primary to secondary tap arrangements. Transformer winding info is like hens teeth. Very hard to find in simple form. If I use the proper gauge wire these cores should be good for at least 100khz
Thanks for the fabulous job you have done with this group buy. Kudos.
Post a sketch of your drv pcb when you get time. The only problem I ever had with the drv was buzzing from the wire layout. It was very hard to get rid of.
Anyone finish there bpa300 projects yet?
Tad
I talked with Rhys today and he has been sick and he did also sound sick. I'll get back to him when I'll get home.
I talked with Rhys and he was on his way to the post office with pcb's and money. If we are lucky I will have them on Friday and by this only a few members are left. Then we are very near an end.
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