|
|||||||
| Home | Forums | Rules | Articles | Store | Gallery | Blogs | Register | Donations | FAQ | Calendar | Search | Today's Posts | Mark Forums Read | Search |
| 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 |
|
![]() |
|
|
Thread Tools | Search this Thread |
|
|
#1 |
|
diyAudio Member
Join Date: May 2010
|
I got a great deal on a 230VAC 160VA toroid from Newark, not realizing that the VA rating would drop running on 115 mains. I now understand that
. So I picked up one of these beasts:Audio Power Transformer 550VA, 59V AC output, Great For Amplifier Projects The manual and many posts here are clear on how to hook up the center tap. Now, my question: Since I have such an overvalued transformer, is there any benefit to using both rectifier boards? And if so, how would I hook it up? I understand the risk of thermal/current runaway with parallel rectifiers, so I'm wondering if there would be a better way to do it... or maybe the center tap admits some simple solution. What do you think? |
|
|
|
#2 |
|
diyAudio Member
|
Not much sense in using two boards in parallel. Rather use one per amplifier channel.
__________________
If you've always done it like that, then it's probably wrong. (Henry Ford) |
|
|
|
#3 |
|
diyAudio Member
Join Date: May 2010
|
That's sort of what I mean. The basic setup illustrated for a center tap transformer has one rectifier board for two channels. I'm wondering if it's appropriate to use two rectifier boards in parallel with the same transistor, one for each audio channel.
|
|
|
|
#4 |
|
diyAudio Member
Join Date: Dec 2009
Location: Asia and United States
|
If you use two lm3875 then you can use a separate rectification board for each chip.
Those two rectification circuits can be connected to your transformer in parallel and both utilize the center tap for power ground. |
|
|
|
#5 |
|
diyAudio Member
Join Date: Jul 2004
Location: Scottish Borders
|
That 59Vac transformer is actually a 59Vac centre tapped transformer. More often specified as 29.5-0-29.5Vac transformer.
The 29.5Vac only happens when the supply is exactly 115Vac and the load is a resistor that draws exactly the rated current (9.32Aac) from the transformer. You may find that this same transformer when idling along on almost silent signal and maximum mains voltage supply is putting out ~+-45Vdc across the smoothing capacitors. 29-0-29Vac is very high for any chipamp. Check the 3875 datasheet for maximum DC supply voltage to suit different speaker (load) impedance. Check Peter's guidance document.
__________________
regards Andrew T. Last edited by AndrewT; 25th May 2010 at 11:10 AM. |
|
![]() |
| Currently Active Users Viewing This Thread: 1 (0 members and 1 guests) | |
| Thread Tools | Search this Thread |
|
|
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Center tap torroid wiring to peter daniels kit??? | Socrates428 | Chip Amps | 10 | 23rd May 2008 04:45 AM |
| Brians Rev 3 LM3875 Kit and Center Tap Transformer | hotscot | Chip Amps | 3 | 4th October 2006 05:19 PM |
| dual center tap rectifier replacement | dodgerblue | Solid State | 6 | 31st July 2006 05:26 PM |
| transformer with no center tap | traw | Parts | 0 | 3rd June 2006 02:36 AM |
| Transformer Center Tap | dswiston | Parts | 2 | 4th February 2004 03:09 PM |
| New To Site? | Need Help? |
| Page generated in 0.09022 seconds (73.29% PHP - 26.71% MySQL) with 10 queries |