Transformer rating and using the ESP Mosfet Kit... - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 22nd January 2007, 02:53 PM   #1
diyAudio Member
 
Join Date: Jan 2007
Location: South Texas
Question Transformer rating and using the ESP Mosfet Kit...

I have a HK3380 stereo receiver that the cat urinated (not sprayed) on and fried the main circuit board including the big cans. I was mad, but I maintained because it was my fault for not covering with a case of some type. Stupid me! So in a fit or rage (ya, that's probably what it was), I stripped that puppy down all the way. I have the back and bottom of the case put back together and the power supply back in. I have hugh aluminum heatsink with aluminum fins on the back of the plate aluminum. All urine is now cleaned out. That's my long story in short mode.

The transformer states 250V 6.3A with a CT. I took my DMM and measued the AC across the blue and red and it was 73.5. I also measured across the black and then the blue and each read 1/2 of that 73.5VAC. I then went to the ESP pages, asked numerous questions on the PE board and overwhelmed them. I should have went slower. Using the ESP pages as reference I used the formulas and figured that this is a EI 50-0-50 transformer. Probably more like 45-0-45 after ripple effect, diodes, etc. My first question is did I do the math right?

If so, then I have enough heat sink area to place two of the ESP High Power Version mosfet PCBs on the sink. So I think I have chosen the right kit and have enough transformer to driver it right?

I am not an EE, but a hobbiest. I pick things up quickly but will need some help and guidance along the way. There will be stupid questions for you but not me. This is my first post, so I just want to let you guys know what I want to make and need help. The boards will be ordered payday via paypal. I've been told that I must get a Variac for testing to bring up the power slowly so that I don't burn the house down, fry diodes, amps, etc. I will search for one of those and buy one. That's a little further down the road though.

My next step is to buy a screw mount fuse holder. I will wait until I have that but I have some a question on hookup later.

At some point, I hope to make contributions to this board instead of sucking in information. Thanks for acepting me guys~!

Here are a few links to show the progress from this weekend when I started the rampage.

[url]http://home.stx.rr.com/poneal/TransformerInTheStrippedDownCase.jpg[/rul]
http://home.stx.rr.com/poneal/heatsink2.jpg


Paul N. O'Neal
  Reply With Quote
Old 22nd January 2007, 03:05 PM   #2
diyAudio Member
 
sixtek's Avatar
 
Join Date: Jan 2007
[ Link: http://home.stx.rr.com/poneal/heatsink2.jpg ]
  Reply With Quote
Old 22nd January 2007, 03:31 PM   #3
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Default Re: Transformer rating and using the ESP Mosfet Kit...

Quote:
Originally posted by PaulO-PEBoard
I took my DMM and measued the AC across the blue and red and it was 73.5. I also measured across the black and then the blue and each read 1/2 of that 73.5VAC. ...........I used the formulas and figured that this is a EI 50-0-50 transformer. Probably more like 45-0-45 after ripple effect, diodes, etc. My first question is did I do the math right?.......I must get a Variac for testing to bring up the power slowly so that I don't burn the house down, fry diodes, amps, etc. I will search for one of those and buy one......
Hi,
you measured an AC voltage of 73.5Vac and two voltages of ~37Vac. This indicates a transformer running at slightly higher than 70Vac centre tapped with a bit of regulation which is quite normal.

After rectification it should give about+-51Vdc to +-52Vdc

A variac is nice to have.
A mains light bulb in series with the live lead is a MUST HAVE. Build one with a plug top and socket outlet to allow safe switch on of any new build or maintained unit. And keep it where you can find it easily.
__________________
regards Andrew T.
  Reply With Quote
Old 22nd January 2007, 04:21 PM   #4
diyAudio Member
 
Join Date: Jan 2007
Location: South Texas
Default Thanks SixTek for fixing that link

Here is the case I'm working with. I guess I somehow mixed them altogether:

Click the image to open in full size.

Hope it come out. I'm still getting used to this layout. I'm an old foggy usually hanging out on the old style BBS boards.

Paul
  Reply With Quote
Old 22nd January 2007, 11:24 PM   #5
diyAudio Member
 
XEAGLEKEEPER's Avatar
 
Join Date: Jan 2006
Location: central Iowa
The xformer should be beefy enough for the ESP P101.Nice sounding amps!
Attached Images
File Type: jpg p101.jpg (36.3 KB, 275 views)
__________________
Ret. USAF... AKA- Avionic *** Solder slinger for hire...***
  Reply With Quote
Old 28th March 2007, 06:31 PM   #6
Dr_EM is offline Dr_EM  United Kingdom
diyAudio Member
 
Dr_EM's Avatar
 
Join Date: Oct 2006
Location: Swindon
How would the P101 perform with a 300VA 30+30VAC toroid (+/-42vdc) supply into 4ohms? I got the transformer for a different (BJT) design but am seriously looking into the P101 if it will work properly; can't see why not really, should be over 120W or so?
  Reply With Quote
Old 28th March 2007, 08:55 PM   #7
diyAudio Member
 
XEAGLEKEEPER's Avatar
 
Join Date: Jan 2006
Location: central Iowa
It would be feasible take a look at Rod's article
http://www.sound.westhost.com/project101.htm
I used a 800VA 50-0-50 and 44,600uf per rail. My NS-1000's although 8 ohm, don't even get the smallish heatsinks warm at a sustained earbleeding volume level.These amps kick " gluteous maximus"




Dave
__________________
Ret. USAF... AKA- Avionic *** Solder slinger for hire...***
  Reply With Quote
Old 29th March 2007, 12:06 AM   #8
Dr_EM is offline Dr_EM  United Kingdom
diyAudio Member
 
Dr_EM's Avatar
 
Join Date: Oct 2006
Location: Swindon
Cool . A slightly obscure question about it but does it make much of a bang when switched on? You wouldn't need any speaker switching?
  Reply With Quote
Old 29th March 2007, 12:59 AM   #9
diyAudio Member
 
XEAGLEKEEPER's Avatar
 
Join Date: Jan 2006
Location: central Iowa
Not a bit.The only noise when powering on is a momentary(<500msec.)transformer buzz with slight dimming of the overhead lights
It was a little worse before I installed the "softstart"P39.But never any power on/off speaker thump.

One of my next upgrades is to install speaker protect circuit P33.For "just in case" piece of mind...

Dave
__________________
Ret. USAF... AKA- Avionic *** Solder slinger for hire...***
  Reply With Quote
Old 29th March 2007, 06:36 PM   #10
Dr_EM is offline Dr_EM  United Kingdom
diyAudio Member
 
Dr_EM's Avatar
 
Join Date: Oct 2006
Location: Swindon
Ace, my 300VA shouldn't be a problem at all (with 20,000uf per rail). I bought a 50W resistor just in case but everywhere reckons I'd get away without soft start on 300VA

How much was the board in total (with postage). I can get the components quite readily so reckon i'll go with this amp over the K8060 kits I was going to use. It's for a sub, decided the damping on the K6080 might be a bit poor and have heard only great things about the P101 (like tight, controlled bass)

Also quickly, will 0.5c/w heatsink suffice for this amp in the configuration I intend (as a couple of posts back)? I doubt i'd often go near full output anyhow so suspect it's plenty but anyhow
  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
Voltage rating of p-channel MOSFET Tahmid Power Supplies 7 3rd July 2008 09:10 AM
Transformer Rating sushi Pass Labs 12 15th August 2007 05:05 PM
Transformer VA rating?? RyanW Power Supplies 6 11th November 2006 11:23 PM
Transformer VA Rating vs. Current Rating JhonDoe Chip Amps 45 5th June 2004 02:11 AM
Transformer rating, to DC azira Solid State 4 16th December 2003 05:41 PM


New To Site? Need Help?

All times are GMT. The time now is 09:06 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