Bought a XY LM3886 Kit. - Page 41 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th February 2013, 05:39 AM   #401
mirmite is offline mirmite  Sweden
diyAudio Member
 
Join Date: Aug 2012
I am kinda new to building amplifiers and HiFi equipment , buy have been working with electronics for a couple of years now, but build mostly sumo robots and other projects.
have ordered a xykit from eBay, and a speaker protection kit, but have some stupid questions
I am gonna drive a pair of dynovoice speakers. as computer speakers
Dynavoice Magic S-4 EX
to be more specific.

1, can I connect my PC directly to the gain clone without a DAC?
2, what is the best way to regulate the volume, and is there schematics, if its a build
3, is there any other module or PCB that is recommended for me to have in the amp
  Reply With Quote
Old 8th May 2013, 02:23 AM   #402
diyAudio Member
 
Join Date: May 2011
with all things made by xy one has to study the original data sheets then trace the xy board figure out what is missing or different or what size part does not fit on the space they provide so thus making it all the more challenging as to what you can build out of them i think the demand dropped off for them and maybe that brought down the prices as they themselves had realized that their boards had some limitations thus why you get version 5 printed on some boards which makes me think that 4 older versions had problems???
  Reply With Quote
Old 8th May 2013, 04:51 PM   #403
Mihkus is offline Mihkus  Estonia
diyAudio Member
 
Mihkus's Avatar
 
Join Date: Jul 2012
Quote:
Originally Posted by mirmite View Post
I am kinda new to building amplifiers and HiFi equipment , buy have been working with electronics for a couple of years now, but build mostly sumo robots and other projects.
have ordered a xykit from eBay, and a speaker protection kit, but have some stupid questions
I am gonna drive a pair of dynovoice speakers. as computer speakers
Dynavoice Magic S-4 EX
to be more specific.

1, can I connect my PC directly to the gain clone without a DAC?
2, what is the best way to regulate the volume, and is there schematics, if its a build
3, is there any other module or PCB that is recommended for me to have in the amp
I would almost never use opamp as first stage of gainclone.
For volume i would use potentiometer.
Dac might be needed if sound card is horrible.
  Reply With Quote
Old 17th June 2013, 08:24 PM   #404
diyAudio Member
 
Join Date: Jan 2013
Quote:
Originally Posted by avbuilder View Post
The 2.2uF capacitor is the DC blocking capacitor as Andrew mentioned. This means that it prevents DC from entering the amp and destroying your speakers.

You can read about it on the My RefC thread where people have even bypassed it if the DC at output is very low or if your preamplifier already has a DC blocking output cap.

The higher the value of the input capacitor the lower the bass frequencies will cut off (high pass filter as told by Andrew). To explain in a simpler way with an arbitary example, say 1 mfd capacitor will pass frequency of over 40 Hz (so you lose the 20-40Hz band) while a 2.2 mfd one goes down to 20 Hz while a 10 mfd may gown down to 5Hz. Since healthy humans can hear from 20-20KHz, a 10 MFD will be an overkill (and enormous too). One can use from 1 microfarad and above however 2.2 to 4.7 will be the best.

After searching a lot of sites for a good yet small input cap I only found that the panasonic polypropylenes are the ones that fit.
The value of R3 feedback resistor determines the gain of the amplifier.

Polypropylenes are better than polyester ones. Try to find a 2.2 polypropylenes that fit. Wima MKP / FKPs are bigger however you may solder them from below. Here is my schematic and BOM:

Click the image to open in full size.

Click the image to open in full size. Click the image to open in full size.
I was looking for an updated component list for the XY3886 boards is this a good solution? Thanks.
  Reply With Quote
Old 18th June 2013, 08:27 AM   #405
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
No.
The RF input filter is missing.
The decoupling C3 & C4 must be changed from MKP, to ceramic x7r or similar.
C3 is in the wrong place on the sch.
C8 is too small.

The type and/or value of component is far more important than the manufacturer.
But the biggest problem is the semi ground plane that has Power Ground and Speaker Return and Zobel Return and NFB and Signal Return all sharing the same bouncing potential. The three left most ground symbols must all connect directly and must be separate from the eight right most ground symbols.
The PCB must be altered if it still incorporates the shared semi ground plane.
__________________
regards Andrew T.
  Reply With Quote
Old 18th June 2013, 08:51 PM   #406
sereal is offline sereal  Canada
diyAudio Member
 
Join Date: May 2013
Quote:
Originally Posted by Aguilabrava View Post
Here, some pictures including the new PSU with the four Cornell Dubilier 18000uF 50V caps, the new amps, the speakers and the two sources I'm using, iPod Mini and QLS QA350 WAV player. Also, the new Thiele R//L network with bigger inductors and resistors on a PCB board, as Corpius did it.

I know, I have to fix the wire mess, it looks terrible, but this is just for testing purposes. Now I have a very little hum if I get my ear really close to the tweeters, but with the first amps I had NO hum at all, that's why I haven't bothered fixing the mess. But I will eventually do. And yes, the left speaker has a stain on the front, but that's how I got them, I bought them used, but they sound great.

Pemo, I still have to take the picture of the back of the Thiele PCB, I didn't do it now because I have to disconnect it, I'll do it soon.
Woah those caps are $30 each? ( CGS183U050V3C - CORNELL DUBILIER - CAPACITOR ALUM ELEC 18000UF, 50V, +75, -10%, SCREW | Newark element14 Canada )

Will those actually make a noticeable difference? I bought these (since one of the caps that was shipped was damaged) UFW1H103MRD Nichicon | 493-3183-ND | DigiKey and considering 4 of them cost more than the XY board I thought that was expensive.....
  Reply With Quote
Old 19th June 2013, 08:23 AM   #407
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
The amplifier, i.e the PCB and it's components are likely to be about 10% of the completed Power Amplifier total cost.
The 18000uF (=18mF) is part of the PSU. That PSU will account for ~30% of the total cost.

did you read this?
Quote:
The type and/or value of component is far more important than the manufacturer.
__________________
regards Andrew T.
  Reply With Quote
Old 19th June 2013, 01:39 PM   #408
sereal is offline sereal  Canada
diyAudio Member
 
Join Date: May 2013
Quote:
Originally Posted by AndrewT View Post
The amplifier, i.e the PCB and it's components are likely to be about 10% of the completed Power Amplifier total cost.
The 18000uF (=18mF) is part of the PSU. That PSU will account for ~30% of the total cost.

did you read this?
I mostly picked my caps randomly, I assumed the ones shipped weren't good quality considering I couldn't find a datasheet and the price wasn't much. I just went on digikey and grabbed something that looked similar from a reputable manufacture - wasn't a whole lot of science in my decision.

But again, will those expensive caps make a audible difference in the sound? Would the quality of my speakers negate any benefit of going with a more expensive/better component?

I'm pretty new to audio stuff in general and I'm a bit weiry of some of the stuff I read. I understand that on paper it's better - but if I can't tell a difference I don't see the point.

I will be ordering another one of these XY kits and will use the caps it comes with and test if I notice a difference. I'll probably also try some of the mods from this thread and compare it against my 'stock' board.

I have blown my budget by quite a bit on my first amp (though probably not as much as I thought since I ordered multiples of lots of items)
  Reply With Quote
Old 19th June 2013, 03:48 PM   #409
diyAudio Member
 
radiosmuck's Avatar
 
Join Date: Jul 2012
Location: Montreal
Quote:
Originally Posted by AndrewT View Post
The amplifier, i.e the PCB and it's components are likely to be about 10% of the completed Power Amplifier total cost.
The 18000uF (=18mF) is part of the PSU. That PSU will account for ~30% of the total cost.

did you read this?
Is'nt the magic of these amplfiers in the chip and the choice of loudspeakers rather than the changing of a few components?
  Reply With Quote
Old 19th June 2013, 04:15 PM   #410
bcmbob is offline bcmbob  United States
diyAudio Member
 
Join Date: Dec 2009
Location: Bay City, Michigan
Quote:
Originally Posted by radiosmuck View Post
Is'nt the magic of these amplfiers in the chip and the choice of loudspeakers rather than the changing of a few components?
That's an ongoing, never ending dispute/conversation. I'm of the opinion, and by my experience, that the choice of components supporting a chip can make huge differences. That however, is totally non dependent on the cost of those parts. In one case a $9 Audyn Plus input cap performs at 90% -95% of it's big brother the True Copper of same value costing ~ $35. In another a Mundorf AG power cap ($45) produces (allows) more and cleaner bass than it's generic equivalent. I try to read a lot of posts from folks who have installed items on their own builds to get some direction and value considerations. Still end up with a few pieces to put in the "I'll use that later" box.
__________________
Bob M.
"Arrange Whatever Pieces Come Your Way."

Last edited by bcmbob; 19th June 2013 at 04:20 PM.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Hi, New member just bought k272a kit from Oatley Jack5 Tubes / Valves 4 22nd February 2011 01:31 PM
Cheap LM3886 PCB I probably shouldn't have bought. crash42 Chip Amps 17 21st September 2010 06:53 PM
Just Bought a Zaph 5.5 kit... first DIY Humboldt_g Multi-Way 7 29th August 2010 02:16 PM
Bought the kit, now I need parts systemerror909 Class D 2 5th December 2006 05:13 PM


New To Site? Need Help?

All times are GMT. The time now is 10:57 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2