Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

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 15th February 2009, 04:11 PM   #2941
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally posted by h_a
But it would take all day and night to reach operating temperature. Maybe that's a plus rather than a negative.
No the heat (energy) has to be dissipated - the fets +local part would be cooking.
but if one were to operate the amp for 4 or 5 hours of an evening and it takes 24hours to reach thermal equilibrium, then the devices will be cooler during that operating period due to the capacity of the sink to store heat to be released later, i.e. after switch off.
__________________
regards Andrew T.
  Reply With Quote
Old 15th February 2009, 04:40 PM   #2942
rhysh is offline rhysh  United Kingdom
diyAudio Member
 
rhysh's Avatar
 
Join Date: Sep 2008
Location: Southampton
Send a message via MSN to rhysh
Also, will there be any problems using wire wound instead of thick film?
  Reply With Quote
Old 16th February 2009, 10:58 AM   #2943
meemee is offline meemee  Indonesia
diyAudio Member
 
Join Date: Feb 2008
Unhappy newbie need help

hello.

my name daniel, i am newbie.
after i read this thread, i want to build this F5. it seem litle bit simple than
the other f series.

but there's some question about F5 i want to ask?

1. is there any difference sound quality if i change ztx550 to bc560 and ztx450 to bc550.
(because it's difficult to find ztx type in my country, indonesia)

2. when i read f5 pdf files, they write about adjusting P1 and P2. i don't understand this one.
please2 someone tell me, how to adjusting P1 and P2 using digital avo meter.
i only have Digital AVO Meter (not good avo meter but cheap digital avo meter).
i really2 don't know about this P1 & P2 adjusting.
it would be nice if someone can show me with the picture?

3. PSU sector. can i change the toroid tranformer with EI type?
is there any difference sound quality if i change toroid to EI type.

4. in my country if we buy toroid or EI tranformer, they always ask
the VOLTAGE (V) and AMPERE (A) type, not VA type.

ex:- EI trans, single tap 12V and 2A ( 12v/1A )
- Toroid trans, double tap 18v and 3A ( 18v-0-18v/3A)

i know the PSU using tranformer 18V double tap (18v-0-18v).
but how much AMPERE (A) do i need?

Thank you

PS: i am sory if my english not good
  Reply With Quote
Old 16th February 2009, 11:44 AM   #2944
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
let's start with the last question.

Suppose you are looking for a 300VA transformer (EI or toroid).
Take the VA and divide by the total output voltage. If you require 18-0-18Vac centre tapped, then the total is 36Vac
The output current is 300 / 36 = 8.3Aac

Ask for centre tapped 18-0-18Vac 8Aac or 8.5Aac
or
ask for dual secondary 0-18, 0-18Vac 8Aac per winding or 8.5Aac per winding.
__________________
regards Andrew T.
  Reply With Quote
Old 16th February 2009, 11:44 AM   #2945
Zen Mod is offline Zen Mod  Serbia
diyAudio Member
 
Zen Mod's Avatar
 
Join Date: Jan 2003
Location: ancient Batsch , behind Iron Curtain
Default Re: newbie need help

Quote:
Originally posted by meemee
hello.

my name daniel, i am newbie.
after i read this thread, i want to build this F5. it seem litle bit simple than
the other f series.

but there's some question about F5 i want to ask?

1. is there any difference sound quality if i change ztx550 to bc560 and ztx450 to bc550.
(because it's difficult to find ztx type in my country, indonesia)

2. when i read f5 pdf files, they write about adjusting P1 and P2. i don't understand this one.
please2 someone tell me, how to adjusting P1 and P2 using digital avo meter.
i only have Digital AVO Meter (not good avo meter but cheap digital avo meter).
i really2 don't know about this P1 & P2 adjusting.
it would be nice if someone can show me with the picture?

3. PSU sector. can i change the toroid tranformer with EI type?
is there any difference sound quality if i change toroid to EI type.

4. in my country if we buy toroid or EI tranformer, they always ask
the VOLTAGE (V) and AMPERE (A) type, not VA type.

ex:- EI trans, single tap 12V and 2A ( 12v/1A )
- Toroid trans, double tap 18v and 3A ( 18v-0-18v/3A)

i know the PSU using tranformer 18V double tap (18v-0-18v).
but how much AMPERE (A) do i need?

Thank you

PS: i am sory if my english not good


1. you can use these BC types ;

2. when you are ready with all parts , ask again ; in meantime - read again and again all Papa's pdfs ......

3. you can use EI without any harm ........ maybe you just need to use slightly powerful one (comparing to toroid ) because EI have slightly worse power regulation
4. so - you need at least 350VA (VA=W ) EI xformer ; that's 2x18Vac and ~10A

your english is good enough
__________________
my Papa is smarter than your Nelson !
tnx to clean thread ; Cook Book ; PSM LS Cook Book ; Baby Diyaudio FORUM ; Mighty ZM's Bloggg;I'm dumb ; Papatreasure
  Reply With Quote
Old 16th February 2009, 11:45 AM   #2946
labjr is offline labjr  United States
diyAudio Member
 
Join Date: Apr 2003
Location: MA
Default Re: newbie need help

Quote:
Originally posted by meemee
hello.

my name daniel, i am newbie.
after i read this thread, i want to build this F5. it seem litle bit simple than
the other f series.

but there's some question about F5 i want to ask?

1. is there any difference sound quality if i change ztx550 to bc560 and ztx450 to bc550.
(because it's difficult to find ztx type in my country, indonesia)

2. when i read f5 pdf files, they write about adjusting P1 and P2. i don't understand this one.
please2 someone tell me, how to adjusting P1 and P2 using digital avo meter.
i only have Digital AVO Meter (not good avo meter but cheap digital avo meter).
i really2 don't know about this P1 & P2 adjusting.
it would be nice if someone can show me with the picture?

3. PSU sector. can i change the toroid tranformer with EI type?
is there any difference sound quality if i change toroid to EI type.

4. in my country if we buy toroid or EI tranformer, they always ask
the VOLTAGE (V) and AMPERE (A) type, not VA type.

ex:- EI trans, single tap 12V and 2A ( 12v/1A )
- Toroid trans, double tap 18v and 3A ( 18v-0-18v/3A)

i know the PSU using tranformer 18V double tap (18v-0-18v).
but how much AMPERE (A) do i need?

Thank you

PS: i am sory if my english not good


The va of the transfomer is just the V(voltage) x A (current) ie 18v x 8.33 amps = 150 va per winding for 300 va total.

I haven't listened to the Zetex parts vs the other ones. I plan on using the Zetex parts. I'm not sure if there's a difference in sound since the transistors are used for overcurrent protection. I don't think it's part of the audio signal path. Though some people think the amp sounds better with the parts completely removed.

P1 and P2 are used to adjust the bias (operating point) of the output stage. Initially they are set at their minimum so they measure zero ohms then slowly turn them up until you measure .59 volts across R11 and R12.
  Reply With Quote
Old 16th February 2009, 03:36 PM   #2947
Chgill is offline Chgill  France
diyAudio Member
 
Join Date: Feb 2009
Default Copper + aluminium for a heatsink

Hello.

I am new, my name Christian. I plan to construct an F5, beginning by heatsinks. I put one heatsink per channel, composed of two pieces: one of red copper sheet, coming from an old big calculator, with dimensions 400 X 160 X 8 mm, weight 4.5 kg. This sheet is already black mate painted. The second part is an aluminium oxyded heatsink, dimensions 300 X 100 mm, with fins 40 mm.
My intention is to screw the two pieces so that the fins are vertical.
Then mount the mosfets on the copper side, about 40 % from the bottom, spaced 20 cm.
I dont know if this kind of gathering will be sufficient for one channel.
There is another question : what about the contact surfaces of the two metals? Specially, the black paint can remain on the copper or no? I think to put thermal grease at the contact.
Someone can tell me the right method to do?

Thanks
  Reply With Quote
Old 16th February 2009, 03:43 PM   #2948
udailey is offline udailey  United States
diyAudio Member
 
Join Date: Mar 2008
Is that solid copper or is it copper laid on top of something else?
I would remove the paint from at least the side that will contact the heatsink. Polished is the best option but the thermal paste will be helpful. Paint must be removed from where the mosfet will go. It is a really good idea to polish the area where the mosfet will be. Also use paste or a pad at that junction.
The heatsink will probably be fine for one channel. Not stereo, although no reason not to try it with that big slab of copper mounted to the back of it. You will be very evenly spreading the heat with that monster piece of copper so perhaps it will work. Doubtful but it is worth trying. Make sure you can measure the heat around the sink and the mosfets.

Uriah
__________________
purchase LDRs anytime Also try my Resistor Replacers or LDR based Input Selector Email me. diyldr@gmail.com
  Reply With Quote
Old 16th February 2009, 04:21 PM   #2949
meemee is offline meemee  Indonesia
diyAudio Member
 
Join Date: Feb 2008
Default Re: Re: newbie need help

Quote:
Originally posted by AndrewT
Hi,
let's start with the last question.

Suppose you are looking for a 300VA transformer (EI or toroid).
Take the VA and divide by the total output voltage. If you require 18-0-18Vac centre tapped, then the total is 36Vac
The output current is 300 / 36 = 8.3Aac

Ask for centre tapped 18-0-18Vac 8Aac or 8.5Aac
or
ask for dual secondary 0-18, 0-18Vac 8Aac per winding or 8.5Aac per winding.

Quote:
Originally posted by Zen Mod




1. you can use these BC types ;

2. when you are ready with all parts , ask again ; in meantime - read again and again all Papa's pdfs ......

3. you can use EI without any harm ........ maybe you just need to use slightly powerful one (comparing to toroid ) because EI have slightly worse power regulation
4. so - you need at least 350VA (VA=W ) EI xformer ; that's 2x18Vac and ~10A

your english is good enough

Quote:
Originally posted by labjr




The va of the transfomer is just the V(voltage) x A (current) ie 18v x 8.33 amps = 150 va per winding for 300 va total.

I haven't listened to the Zetex parts vs the other ones. I plan on using the Zetex parts. I'm not sure if there's a difference in sound since the transistors are used for overcurrent protection. I don't think it's part of the audio signal path. Though some people think the amp sounds better with the parts completely removed.

P1 and P2 are used to adjust the bias (operating point) of the output stage. Initially they are set at their minimum so they measure zero ohms then slowly turn them up until you measure .59 volts across R11 and R12.

waaahhhh... thank you very much for the fast answer....

about P1 and P2, first set to 0 ohm then slow turn until 0.59v across R11 and R12...thank you...

so, the toroid transformer between 8A and 10A. ooooohh......it will cost lot of my money.....

once again thank you very much........

to buy this toroid transformer.
  Reply With Quote
Old 16th February 2009, 04:50 PM   #2950
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
any ClassA amplifier will cost many times the same power from a ClassAB amplifier.
__________________
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Rockford Fosgate Power 20001 bd amplifier power rating?? pachoorion Car Audio 8 8th May 2011 10:49 PM
Power transformers versus amplifier output power..what is your option? destroyer X Solid State 38 9th May 2009 05:23 PM
McIntosh Power Amplifier Power Guard johnnyrt Solid State 2 23rd August 2007 10:22 PM
Output power for a power amplifier Progg70 Solid State 33 10th September 2006 08:44 AM
Amplifier 3000 Wats Rms Power + Smps Higcht Power Bestiality MARAVILLASAUDIO Class D 1 5th November 2004 04:06 PM


New To Site? Need Help?

All times are GMT. The time now is 05:55 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