a few questions about this TA2020 board - diyAudio
Go Back   Home > Forums > Amplifiers > Class D

Class D Switching Power Amplifiers and Power D/A conversion

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 8th January 2009, 01:34 PM   #1
diyAudio Member
 
Join Date: Jul 2008
Default a few questions about this TA2020 board

Just got done building a pair of Zigmahornets. Now trying to get an amp to drive them.

I bought an assembled TA2020 board from ebay. It's the same board as in this:
http://www.hllyelectronics.com/html/...tter_1_97.html

The problems are:

1. One of the capacitors (the green one on the top right of the first picture of the board) had a broken leg. What's left is probably too short to be re-soldered onto the board. For a complete newbie like me, I'd appreciate some spoon feeding on what to replace it with. I'm guessing it's a "polyester film" type. It says "104K", then under that "1HD(N)" (N is in a circle). The schematic the seller has on his site shows 104 at this spot. I gathered this is a 100,000pF. I looked on partsexpress.com, but the caps there also have a voltage rating. Not only that, but there are also electrolytic ones. So the questions are 1a) what can I replace this cap with (i.e., what voltage), and 1b) should I stick with polyester film, or would electrolytic be better?

2. While we're on the subject of the capcitor, can anyone suggest possible upgrade to what's on the board? The big cap is an Elna 2200uF. Would this be a good one, or are there better choices?

3. For input, the board has a "standard 2.54mm pcb board connector" (the white part in the bottom right corner of the 3rd picture). Where can I find a plug that can fit? Also, there are three pins, IN1, IN2, and GND. I suppose I'd connect the R+ and L+ to the IN1 and IN2, and R- and L- both to GND? If not, what's the right connection?

TIA for your help!!

Andy
  Reply With Quote
Old 8th January 2009, 02:13 PM   #2
diyAudio Member
 
Join Date: Feb 2006
Location: Chicago, IL
Hi Fishline,

Looks like a pretty good board, actually.

Yes, I think a film cap, and I would replace it with the same type, not an electrolytic. 100,000 pf should be 0.1 uf (somebody check my math). Voltage rating here is unimportant, as the films cap voltagfs are all way above what's needed for functionality.

Second, 2200 uf is probably all you need for this board. You might check the specific Elna series number to see if there might be a higher grade of cap (low ESR/low impedance) to replace it, but I'm guessing any change is going to be marginal. Input caps (the big squarish ones) are probably the ones that affect the sound most directly. Search these forums, as there have been a few capacitor shootouts and much lively debate. Looks like the board has multiple holes to caps of different sizes could be fitted.

As for the input, you've got it right. One thing you might do is desolder the pin connector and replace it with a small screw terminal. Radio Shack sells twosies that snap together. You could use two and just leave the fourth unconnected with its pin trimmed off. Or, if you're placing an order with Mouser or Digi-Key, get a three-terminal one. Spacings vary; be sure to check.

As long as you're adding screw terminals, you could do the same for speakers and power. Makes it a lot easier if you're constantly tinkering, as circuit board solder pads tend to come loose after repeated reheating.

Have at it!

--Buckapound
  Reply With Quote
Old 8th January 2009, 07:37 PM   #3
v-bro is offline v-bro  Netherlands
diyAudio Member
 
v-bro's Avatar
 
Join Date: May 2006
Yep, 0,1uF or 100nF...

It looks like a film cap of some sort indeed. It is NOT possible to use electrolytic caps as replacement!

Look for polyesther. I would take a 100V cap to be safe...watch the pitch to make sure it fits nicely!
__________________
Max. cone displacement can be several foot on any speaker!Too bad it can be done only once......
  Reply With Quote
Old 9th January 2009, 03:03 AM   #4
diyAudio Member
 
Join Date: Jul 2008
You folks are extremely helpful! I'll get the 100v 0.1uF film caps.

Can you please show links to the screw terminals at either Rat Shack site or any other? (I'm going to get the caps from partsexpress.com, so if they have it, that'd be great.) I tried searching on rat shack and partsexpress, and got either no hits. mouser's search is rather over my head.

Also, what gauge wires should I use to connect things?
  Reply With Quote
Old 9th January 2009, 07:20 AM   #5
v-bro is offline v-bro  Netherlands
diyAudio Member
 
v-bro's Avatar
 
Join Date: May 2006
Here's an example at Farnell:
Click the image to open in full size.

http://nl.farnell.com/imo/20-101m-2/...way/dp/9632670

But also here you have to be very sure about the pitch (distance between the pins) And indeed what wire gauge you want to use them with...

Most of the wiring can doesn't have to be very thick I'd say 0.2AWG will do, but the wires between the amp and power supply can best be pretty thick like 0.8AWG. (I hope I did my math right, I'm not so into American wire gauges....)
__________________
Max. cone displacement can be several foot on any speaker!Too bad it can be done only once......
  Reply With Quote
Old 9th January 2009, 01:02 PM   #6
diyAudio Member
 
Join Date: Feb 2006
Location: Chicago, IL
American wire gauge is some holdover relic of ancient days. The higher the number, the lower the size.

Short runs of speaker and power wire are fine at 18 gauge or so for a small amp like this. Signal wires are often something like 26 gauge.

I can't find the terminals on the Radio Shack site, but if you go to a store, they're hanging on the pegboard right near the printed circuit boards and things like that. Just like V-Bro showed, only peacock blue.

--Buckapound
  Reply With Quote
Old 9th January 2009, 03:36 PM   #7
v-bro is offline v-bro  Netherlands
diyAudio Member
 
v-bro's Avatar
 
Join Date: May 2006
Ok, thanks Buckapound, then I was way off there

I just didn't seem to have the right table and just calculated the wrong way around...
__________________
Max. cone displacement can be several foot on any speaker!Too bad it can be done only once......
  Reply With Quote
Old 10th January 2009, 04:10 PM   #8
diyAudio Member
 
Join Date: Jul 2008
Thanks! I had to go to two Radio Shack stores to find the terminals. They only have one pitch size and it didn't fit any of the parts on the amp board. Oh well. I ended up just solder wires longer than I need onto the board. Will trim them once I finalize the arrangement.

Got the amp going last night. Quite nice!

One more spoon-feeding question: The two caps next to the input look like they have adjustment screws on top. What are they for, and do I need to check them? If so, how? (They are marked "64W 50K-K".) Actually I don't know if they are capacitors. The markings on the board say "Rx1" and "Rx2".
  Reply With Quote
Old 10th January 2009, 11:13 PM   #9
v-bro is offline v-bro  Netherlands
diyAudio Member
 
v-bro's Avatar
 
Join Date: May 2006
Hi,

no they are potmeters (variable resistors), I think you can adjust the DC offset with them (DC voltage on the outputs, ideally this voltage is zero. If you have a multimeter I recommend you give it a try! )
__________________
Max. cone displacement can be several foot on any speaker!Too bad it can be done only once......
  Reply With Quote
Old 10th January 2009, 11:30 PM   #10
diyAudio Member
 
Join Date: Jul 2008
Ah... So I hook the meter up to the speaker out (one channel at a time) and adjust until I get 0v?
  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
Grounding & board Layout questions Valvomaniac Tubes / Valves 1 26th April 2007 03:56 AM
tech-diy LM4780 board questions Original Burnedfingers Chip Amps 1 13th January 2007 02:06 PM
Tripath TA2020-020 6 Channel Amp Board john65b Swap Meet 0 10th October 2005 12:20 PM
Tripath TA2020-20 6 Channel Amp Board john65b Class D 1 21st September 2005 04:43 AM


New To Site? Need Help?

All times are GMT. The time now is 10:41 AM.


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