Buffer Ampifier

[brombo]

I am looking for a design and a place to fabricate (circuit board?) a line level audio input buffer amplifier for the icepower amplifier I am building. I was thinking of using a OPA1692 op amp but could use a circuit and a place to fabricate the circuit board. Eventually I would need six or eight channels of buffering. Any advice is welcome. I am in Silver Spring.

[tomp]

I would suggest also looking at the LME49860 which is the replacement for the LME49720 which has been my go to OP Amp. It has lower noise than the OPA1692, bus input voltages up to + _ 22 volts that will provide more head room and a higher gain/bandwidth product which will provide better performance in feed back operations. For my PC boards, I use the free application from ExpressPCB to design them and then email the resulting file to them for fabrication. Their prices are reasonable and the boards are high quality. The application is relatively easy to use.

https://www.expresspcb.com/

Tom

[brombo]

Do you have a possible circuit diagram (schematic)?

[Guy]

If you are looking for a Printed-Circuit-Board company, I have used Pad2Pad a few times and their work is very good. I believe that they also place part or all of the components, but I haven't done this before. It would be handy for the surface-mount components we are being forced to use these days.

You need to download their free program and lay out the board with it. You can then choose a quantity and see the price before placing orders. I like knowing the cost before ordering.

I have used FreePCB in the past as well. They have a new version that requests a $10 donation is you use it, or you need to post it on your web page if you have one. This program generates Gerber files that you can send to any PCB company for manufacture. You can search for them online.

[Stuart Polansky]

Are you looking for a proven design using the op amp of your choice? Do you want to design your own circuit? Are you looking just for a PCB manufacturer? Or, are you looking for an already designed circuit?

If it's the latter, and solid state is your preference, then consider this Nelson Pass discrete design.

https://diyaudiostore.com/collections/p ... -b1-buffer

Hope this helps

Stuart

[brombo]

I have ordered LME49960NA DIP8 opamps from China (Amazon). I could only find US sources for surface mounts. The Icepower amplifier application notes have a simple opamp circuit for a buffer and the amplifier boards can supply the voltages (bipolar) needed by the opamps. What sources do you use for resistors, capacitors, and ic sockets. I have used Mouser before. Any other suggestions. Also I have gotten this case from Amazon -

https://smile.amazon.com/dp/B08NGGMKC3?psc=1&ref=ppx_yo2_dt_b_product_details

I also found these (made in Thailand) and wondered if anyone here had bought any before -

https://www.ebay.com/str/chevalgrp/Electronic-Enclosure/_i.html?store_cat=25167338010

The amplifier will have three channels (two icepower boards). One stereo board at 50W per channel and one 200W mono board. It is for a single triamplified speaker, 10 inch midbass (200W), horn midrange (50W), and horn tweeter (50W).

[tomp]

For passive components, I have used Newark, Digikey, Mouser, Allied and ebay. For resistors, I have complete sets of metal films because you have all values on hand and it is much less expensive that buying singles. Some semiconductors like diodes, comparators, and small transistors are cheaper to buy by the hundreds when you consider that the freight is usually more than the cost of the components.

Tom

[brombo]

Amplifier boards in cabinet. Small board is stereo 50W per channel. Large board is mono 200W. Both boards have built in power supplies (120/240 VAC input) -

[brombo]

Some progress. Now it is on to laying out the buffer circuit board.

Attachments

[Guy]

Keep us updated!