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Old 10th November 2017, 01:05 PM   #1321
xrk971 is offline xrk971  United States
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Quote:
Originally Posted by stellarelephant View Post
Sheesh that's cheap! I will have a look. Have you built a LM3886 also?

So is matching impedance between the preamp and power amp as simple as matching with headphones--i.e. coupling with enough capacitance to ensure bass response?
There is no impedance matching issue. Most chipamps have a 10k to 100k input impedance. The PCA can drive 60ohm impedance if needed, so 10k is nothing.

Chip amps are cheap indeed - good ones with nice components will run you about $40.

I have pre-built LM3886's, but not built it myself, no point when they are so inexpensive fully-built. I have one just like this (without the HS it was $40. It sounds quite decent and has ability to change out input opamp stage).

NEW LM3886 Full DC servo Redux Immersion Gold Process 68W+68W 5534 independent op amp amplifier finished board with heatsink-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

This looks nice too and has output Thiele network (inductor).
NOVER LM3886 NE5532 HIFI audio amplifier board stereo 2.0 channel hifi amplifier 68W * 2 CG version LM3886 power amplifier board-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group
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Last edited by xrk971; 10th November 2017 at 01:10 PM.
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Old 10th November 2017, 05:42 PM   #1322
royalmp is offline royalmp  United States
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Thanks for the reply , xrkaudio,
If you look at your post at the very beginning of this thread, your third schematic, showing the two channel config, Q1 and Q2 are labelled SST201, which are actual FET numbers.
?????
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Old 10th November 2017, 05:53 PM   #1323
stellarelephant is offline stellarelephant  United States
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Nice. If impedance doesn't matter, maybe it is just a matter of "synergy." Have you paired a PCA with your LM3886 before?

My goal would be to couple the preamp with the amp using a single PP or PPS film cap if possible. If the cap is preferred near the load, I guess that would dictate that I should leave the output cap off of the PCA board and just have a film on the input of my amp.
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Old 10th November 2017, 07:52 PM   #1324
stellarelephant is offline stellarelephant  United States
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Trying to get started on the Raptorlightning Cap Mx for my amp. The words printed onto my OSH Park PCBs are absoluetly tiny and hard for me to read. That, plus the fact that one pair of pads isn't labeled, led me to make this little assembly roadmap. I believe the unlabeled pads are for R2.

I tried to deduce the positive and negative pads for the 100uF cap as well, by looking at the board design and the schematic, and I labeled those in the image. This is important for me, as I am using a polarized electrolytic cap here and I don't want to blow it up. Noob alert.

Buzz, Raptor, or X, can you confirm that I got the polarity right?
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Old 10th November 2017, 08:19 PM   #1325
randytsuch is offline randytsuch
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Quote:
Originally Posted by xrk971 View Post
I am offering free shipping in continental U.S. on Nov. 11 (Eleven-Eleven sale) for 1-day only on all items in my shop.
I was going to say I still see a shipping cost, but then I realized its only the 10th
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Old 11th November 2017, 10:37 AM   #1326
yourownbuzz is offline yourownbuzz
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yep, stellar, that is the correct polarity (same orientation as I used anyway - we could both be wrong, but it works)
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Old 11th November 2017, 01:01 PM   #1327
stellarelephant is offline stellarelephant  United States
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Thanks
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Old 11th November 2017, 02:29 PM   #1328
randytsuch is offline randytsuch
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Just ordered a pcb and transistors from etsy. Need to buy rest of the parts.
Wondering if anyone has an extra RaptorLightning pcb?

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Old 11th November 2017, 03:01 PM   #1329
xrk971 is offline xrk971  United States
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Thanks for the order.

The free shipping in US sales event code is ELEVENELEVEN.
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Old 11th November 2017, 03:15 PM   #1330
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I thought it just gave me free shipping? At least I hope so lol
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