Want to build my first amp - Page 3 - 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 27th October 2004, 08:16 AM   #21
Jennice is offline Jennice  Denmark
diyAudio Member
 
Join Date: Jun 2003
Location: Planet Earth
Still4given,

I wouldn't worry too much about your transformers not being torroids.
Their main advantage is a lower spreading of magnetic field. However, field strength decreases (if I recall correctly) with distance^3, so a little more distance, and suitable orientation of the PCB's relative to the transformer should solve this problem (which is mainly a problem when you stress the transformer). Look at the transformer, and try to see the orientation of the coils. This will also be the direction of the magnetic field emmitted (which may leak from the core), going in a circle path back to the other end of the transformer coil. Worst case is to have this field going straight through the plane of your PCB, as conductors of your PCB will act as windings, causing induction error (noise, hum) voltages.
In real life, though, I have found this to be a minor problem only.

Depending on type of transformer (torroidal, EI core, UI core etc), there are differences in output impedance (voltage "stiffness" or load-independence/regulation) for a given VA rating, but as long as you use big transformers (say, 4 times the estimated wattage rating of the amp), I have found this problem to be neclectable. A healthy ammount of storage capacity lowers the PSU impedance drastically, anyway.

another thing... Use plenty of output devices. The phase of a speaker will cause losses bigger than the obvious U * I calculation, so it's a good idea to use plenty of devices (they'll run cooler, too!) for a given amp and heat sink.

Jennice
__________________
I get paid to break stuff. My g/f gets paid to play with children. Life is good.
  Reply With Quote
Old 28th October 2004, 08:07 AM   #22
Jennice is offline Jennice  Denmark
diyAudio Member
 
Join Date: Jun 2003
Location: Planet Earth
Still4given,

Maybe you'll find the PDF on ftp://sylvest.dyndns.dk/ useful. Please let me know what you think. It's on my own server (which is down occasionally - it's experimental)), so please download it in stead of reading it directly from the server.

Jennice
__________________
I get paid to break stuff. My g/f gets paid to play with children. Life is good.
  Reply With Quote
Old 28th October 2004, 01:43 PM   #23
diyAudio Member
 
Workhorse's Avatar
 
Join Date: Dec 2004
Arrow WELCOME HOME TERRY

HI TERRY WELCOME TO DIYAUDIO

PLZ FEEL FREE TO ASK FOR ANY ASSISTANCE FROM US.

WITH REGARDS
WORKHORSE TECHNOLOGIES
  Reply With Quote
Old 28th October 2004, 02:48 PM   #24
Jennice is offline Jennice  Denmark
diyAudio Member
 
Join Date: Jun 2003
Location: Planet Earth
AmpMan1,

Please keep ypur post in normal writing style. All capitals is annoying to read (for me, anyway), and considered as shouting (from my old chat-days). I admit that I have used capitals occasionally to emphasize (spelling?) something, but not the entire text...

Jennice
__________________
I get paid to break stuff. My g/f gets paid to play with children. Life is good.
  Reply With Quote
Old 28th October 2004, 02:57 PM   #25
diyAudio Member
 
still4given's Avatar
 
Join Date: Oct 2004
Location: Victorville, CA
Hey Jens,

Thanks for the link. What a great resourse! I will be studying it in debth.

Hey amp_man,

Thanks for the kind welcome and offer of advice. I'll be taking you up on that.

Blessings, Terry
__________________
X-BoSoZ, B1 Mezmerize, ESP P101, Symasym, KSA 50 X 2 Aleph-X, Leach Low TIM, Leach Superamp, Dx MKIII, DX Super A, Honey Badger, JLH 1969, Gainclone. FetZilla, Peeceebee X2, VSSA PMI, VSSA jkuetemann, SKA GB150, Ovation nx, Slewmonster with; CFA-XH, Wolverine, Spooky, Symasui, Low TIM hybrid
  Reply With Quote
Old 28th October 2004, 03:01 PM   #26
Jennice is offline Jennice  Denmark
diyAudio Member
 
Join Date: Jun 2003
Location: Planet Earth
Still4given,

Thanks, I'm glad you like it !

Jennice
__________________
I get paid to break stuff. My g/f gets paid to play with children. Life is good.
  Reply With Quote
Old 31st October 2004, 01:50 AM   #27
diyAudio Member
 
still4given's Avatar
 
Join Date: Oct 2004
Location: Victorville, CA
OK, guys. I've purchased three of the P101 boards from ESP. Rod said it should take a couple of weeks for them to arrive. I have already ordered most of the parts for them. I will have to start thinking about a PSU. I would really like to use one of XL-280 transformers if there is a way to make it work. They have +two separate secondary outputs. Three really but the one is only like 6V or something I'm told. The one that gets hooked up for the Hafler DH200 is 65-0-65 I believe. At least that's what it measures at the Filter caps. I'm told the other set puts out 70-0-70 and is for heating up the MOSFETs. I'm not sure if it has enough amps to do anything else. I know the XL-280 uses 4 filter caps as opposed to 2 caps for the DH-200.
Anyway, do any of you know if this tranny will have enough juice to run the P101? I bought three boards planning to make this a three channel like the Bryston 5B. I want to use it for the front end of a 5.1 setup.

So what do you guys think? Dumb idea? Would three channels tax the tranny too much?

Thanks, Terry
__________________
X-BoSoZ, B1 Mezmerize, ESP P101, Symasym, KSA 50 X 2 Aleph-X, Leach Low TIM, Leach Superamp, Dx MKIII, DX Super A, Honey Badger, JLH 1969, Gainclone. FetZilla, Peeceebee X2, VSSA PMI, VSSA jkuetemann, SKA GB150, Ovation nx, Slewmonster with; CFA-XH, Wolverine, Spooky, Symasui, Low TIM hybrid
  Reply With Quote
Old 31st October 2004, 02:51 AM   #28
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
Well, to begin with 65-0-65 is suitable for a 400W/channel amp _ approximately. I think that might be pushing the P101 beyond what it was intended to handle unless you want to experiment with Exicon "double die" MOSFETs and a really big heatsink.

On the other hand if you truly have two secondaries and not just one with a center tap you can parrallel them have have something suitable for ~100W/ch. 32.5/35 - 0 - 32.5/35

This will work
__________
( +65/70
(
(
(__________ 0

__________
( 0
(
(
(__________ -65/70

This will not allow you to parrallel
________________
( +65/70
(________________
( 0
(________________ -65/70

Assuming you can parrallel them, your thansformer will not have a 0V reference, so take a look at Rod's project on how to create one - you just need to be sure to use appropriate resistors in the case of figure 1. (I use this set up for a bench power supply to check new amps.) Figure 2 ought to work as well so ong as you use 15V zeners to power the opamps.
  Reply With Quote
Old 31st October 2004, 04:01 AM   #29
diyAudio Member
 
still4given's Avatar
 
Join Date: Oct 2004
Location: Victorville, CA
Wow, my Haflers are just 115WPC. The use the Hitachi MOSFETs and pretty big heatsinks though. I already bought the MOSFETs for the P101. They are the 2SH1058 and 2SJ162.

The manual for the P101 has this warning;

Warning: The power supply voltage used for this amplifier is potentially lethal! With +/- 70V, the total voltage is 140V which can kill you!

Maybe I'm misrepresenting my transformer. I just looked at the recomended power supply for the P101 and it shows a 50-0-50 Transformer but after rectification it is showing +70,-70 rails with 6x4, 700uF/80V caps. My Hafler only has 65V rails with 2-10000uf/75V caps.

Maybe my tranny is too small for this amp. Any idea?

Thanks Terry
__________________
X-BoSoZ, B1 Mezmerize, ESP P101, Symasym, KSA 50 X 2 Aleph-X, Leach Low TIM, Leach Superamp, Dx MKIII, DX Super A, Honey Badger, JLH 1969, Gainclone. FetZilla, Peeceebee X2, VSSA PMI, VSSA jkuetemann, SKA GB150, Ovation nx, Slewmonster with; CFA-XH, Wolverine, Spooky, Symasui, Low TIM hybrid
  Reply With Quote
Old 31st October 2004, 06:55 AM   #30
Jennice is offline Jennice  Denmark
diyAudio Member
 
Join Date: Jun 2003
Location: Planet Earth
Sam9,

How do you get away with this...!? I my book it's not possible to get +/- 32V, unless there are really 4 identical secondaries.
The only work-around is to parallel and get one 65V secondary, and then some added electronics to get this made symmetrical. Personally, I don't like that approach, especially not with these power levels, as the output impedance of the transformer is hot used to maintain the 0V reference point.


Terry,

What kind of transformer is it? (torroidal, EI core...?)
(somehow I have the feeling I've already asked this once before )

What's the weight of it? If you take the weight for a given core type transformer, you can often get an idea of VA rating, by comparing it to those in electronic shops.


Jennice
__________________
I get paid to break stuff. My g/f gets paid to play with children. Life is good.
  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
I want to try and build my own DAC gareth Digital Line Level 3 3rd July 2009 03:20 PM
ZV9 build ingi Pass Labs 8 6th August 2006 02:40 PM
build my first full ranger,let's build another one:a small fullrange high end pc-spea then_dude Full Range 2 30th November 2005 07:54 AM
Do i need to build main supply (240v) filter?Or build power distribution? thomgun_lc Chip Amps 9 16th September 2005 09:52 AM


New To Site? Need Help?

All times are GMT. The time now is 05:45 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