Power amp under development - Page 280 - 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 24th May 2008, 11:08 PM   #2791
diyAudio Member
 
keypunch's Avatar
 
Join Date: Sep 2004
Location: Willowdale
Quote:
Originally posted by kalmara
Hello, Quasi. I preformed a search with keywords "Nmos200 BOM", but didn't found anything like this for any of the Nmos amps. Do you have such a bill of materials, and if not - could you please comply one using your schematic design program. Thanks.
Kalmara,

quasi posted a "Cost Estimate" in Post #141 which is as close to a BOM as you will find thus far. Please be aware since quasi posted the "Cost Estimate" the NMOS200 (TO-220) variant has been posted which the "Cost Estimate" does not account for nor the corrections or refinements that the NMOS350 has had since the "Cost Estimate", i.e. different PSU voltages, usual corrections, NMOS500.

I hope the initial "Cost Estimate" quasi posted will serve as a starting point for your build of the quasi NMOS amp.


Regards,

John L. Males
Willowdale, Ontario
Canada
24 May 2008 (17:05 -) 19:08
Official Quasi Thread Researcher

P.S. Sorry folks, but I have been dealing with a number of, and continue to, crisis the last few months. jlm
__________________
P.S. My appologies in advance for any typo errors. If you cannot "decode" the typo or feel there is a typo (some typos are correctly typed spelling, but can be mix of wrong/omitted words) speak up and ask me to clarify. jlm
  Reply With Quote
Old 25th May 2008, 10:53 AM   #2792
sek is offline sek  Germany
diyAudio Member
 
sek's Avatar
 
Join Date: May 2003
Location: Berlin
Quote:
Originally posted by keypunch
P.S. Sorry folks, but I have been dealing with a number of, and continue to, crisis the last few months.
John, I hope you're going along well!

Cheers,
Sebastian.
  Reply With Quote
Old 27th May 2008, 10:37 PM   #2793
diyAudio Member
 
Join Date: Oct 2006
Location: delhi
hi quasi im a newbie and have build your nmos200 with irfp450,mje340/350 and supply of +-43v dc what is its output

and what if i increase the value of r3 e.g 82k
  Reply With Quote
Old 28th May 2008, 01:02 AM   #2794
quasi is offline quasi  Australia
diyAudio Member
 
quasi's Avatar
 
Join Date: Sep 2004
Location: Adelaide, Australia
Hi Ravslanka,

At best your amp module will deliver about 70 watts into 8 ohms and about 130 watts into 4 ohms depending on the size and quality of your power supply.

R3 in part sets the input impedance and should not be changed. It has no bearing at all on the output power.

Hope you enjoy your amp.

Cheers
  Reply With Quote
Old 28th May 2008, 10:05 AM   #2795
diyAudio Member
 
Join Date: Jun 2004
Location: HKSAR
Hi Quasi,

Sorry to bother again. I have come across some soft-starter circuit saying that the delay time can be order of seconds. I am quite stuck by this kind of timing. The resistors will be heating up a lot for delay time of seconds, won't they? What's the delay time for your circuit then? Because I am integrating it into a circuit with a speaker protection which has 1. a delay time on, 2. DC detection and 3. a thermal detection . If your delay time is longer than that of the speaker protection, it won't mean anything at all (I mean it should be shorter than the speaker protection delay, should'n it? Or it won't be serving its function? )

Some said that it should be in terms of 0.2 - 1 sec. What 's on your mind about this? It won't matter if it is 0.2 or 0.5 sec. But I think it does if it is 0.2 or 2 sec.

Tks
  Reply With Quote
Old 28th May 2008, 10:36 AM   #2796
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
soft start is to allow toroids and big EI to establish flux.
This takes just a few cycles from off.
The delay on the resistor bypass is effective even if set to as low as 100mS.
It does not need to be 500mS or 1S or 2S.
__________________
regards Andrew T.
  Reply With Quote
Old 28th May 2008, 11:27 AM   #2797
quasi is offline quasi  Australia
diyAudio Member
 
quasi's Avatar
 
Join Date: Sep 2004
Location: Adelaide, Australia
Hi BigPanda,

AndrewT is quite correct. My softstart delay is about 250mS and seems to do the job. Too long a delay could as you suggest be a problem for the resistors, but this would depend on the size of the power supply (including capacitors) you were trying to start up.

Cheers
Q
  Reply With Quote
Old 28th May 2008, 08:03 PM   #2798
diyAudio Member
 
Join Date: Oct 2006
Location: delhi
hi quasi thanks for your support and providing such a great amp which works on the first attempt
i will be posting the pics soon

one more question i want to build your n channel bipolar350 but
mje15030/31/32,33/34,35 are not available here so may i go with mje340/350
  Reply With Quote
Old 28th May 2008, 08:39 PM   #2799
diyAudio Member
 
megajocke's Avatar
 
Join Date: Jan 2003
Unless it's a class A amp essentially the same energy will be taken up by the soft start resistors independent of the time they are switched in if the time is long enough for the caps to charge up fully. The energy dissipated will be the same as the energy stored in the caps when full. (When charging capacitors full through resistors the same energy is lost in the resistor as is stored in the cap when full)

I wouldn't recommend switching out the resistors before the caps are full, the flux can't reach steady state while the caps are clipping the voltage waveform.
  Reply With Quote
Old 29th May 2008, 08:31 AM   #2800
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
use a second slow charger with bypass in the secondary if smoothing capacitance peak/sustained current is worrying you. This better suits a power thermistor to maintain a good current flow as the caps charge up.

Save the slow start for it's specific purpose. To get the transformer started without requiring a (useless) enormous fuse value.
__________________
regards Andrew T.
  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



New To Site? Need Help?

All times are GMT. The time now is 02:27 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