Anyone interested in PCB's for OPA627/BUF634 based headphone amp? - Page 2 - diyAudio
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Old 10th December 2004, 06:40 PM   #11
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I've put up a simple page with files you can download.

Headphone Amp
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Old 11th December 2004, 12:55 AM   #12
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I like it. The schematic looks pretty versatile, you can build to suit, add or remove parts. The only shortcoming I see is the simple class-A biasing (2.49k, R3,41,52,53), I'd rather use active current sinks, but they could be kludged in. SO8 footprints would be nice too, but if only one choice is available I'd take DIP8 and use SO8 adapters if needed.

How do the versions with BUF634 and CF opamp as output buffer compare?

I'll wait for announcement of purchase arrangements before buying a PCB
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Old 11th December 2004, 01:11 AM   #13
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Quote:
Originally posted by nuvistor
I like it. The schematic looks pretty versatile, you can build to suit, add or remove parts. The only shortcoming I see is the simple class-A biasing (2.49k, R3,41,52,53), I'd rather use active current sinks, but they could be kludged in. SO8 footprints would be nice too, but if only one choice is available I'd take DIP8 and use SO8 adapters if needed.
The biasing resistors were not included on the original circuit I did so I ended up soldering resistors directly to the IC's. I later added the resistors to the schematic and layout incase I were to order more.

Quote:
How do the versions with BUF634 and CF opamp as output buffer compare?
I never built the circuit using a current feedback opamp so I can't comment on differences. But the layout has the feedback resistors for a CF opamp if you choose to use one.
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Old 12th December 2004, 01:03 AM   #14
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I've got 7 people who are interested in the headphone amp PCB. At these smaller quantities my cost for the boards are $10 each + $10 shipping. So if I order 7 that would be $70+$10 shipping = $80 / 7 = ~$11.50 each.

I have all the surface mount resistors on hand. I can provide all of them (49) for $3.00. They are KOA 1% metal-film (RK73H series).

U.S. shipping is $5.
Int'l shipping is $10.

Let's get a recount based on these numbers. If you would, please send me an email so I can contact each of you directly if need be.

Thanks.
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Old 13th December 2004, 01:42 PM   #15
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Fine
Include me for 2 boards
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Old 13th December 2004, 04:33 PM   #16
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I've got 7 folks comitted to the headphone PCB purchase. If you want in, please send me an email as I plan to order boards by the end of this week.

Look a few posts back for pricing info.
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Old 16th December 2004, 02:27 AM   #17
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There are a couple of folks whose email address I do not have who have expressed interest in the headphone PCB:

earsandeyes and paulb

I'm now collecting money to order the PCB's so please make payment this week if you still want to get in on the deal.


Thanks,
Rob
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Old 16th December 2004, 05:13 AM   #18
janusz is offline janusz  Australia
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Default PCB for the K's headphone amp

Hi Maxhawk,

I just started to write this email and somehow I must have pressed the wrong key and it has posted itself with just 'Hi'.

Anyway, I would be interested in two PCBs for the headphone amp. The only question is how do I sent money to you? Have you got a PayPal account?

And how much would it be together with the cheapest air mail to Australia?

My direct email addres is:
janusz.pradzynski@dpi.wa.gov.au

I should be grateful if you managed to answer my email before it's too late. The above is my work address (I have no home address yet) and I will be here today until 5PM Perth (Singapore) time zone and of course i'll be at work tomorrow.

Cheers,
Janusz
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Old 17th December 2004, 06:13 PM   #19
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Just want to let everyone know that I ordered PCB's today for the headphone amp. There are a couple people who have not paid yet, but I have enough to cover you.

The vendor has a ship date of 29-Dec so it will be the first week of January before I can ship anything out.

Happy Holidays!
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Old 17th December 2004, 07:42 PM   #20
sklimek is offline sklimek  United States
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Thank you Maxhawk, I look forward to it. Nicely done and it was great to see the crossfeed filter as well as the 4 seperate gain stages incorporated into the design as well.
Merry Xmas - Stan
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