Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

P27 Output Voltage
P27 Output Voltage
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
Old 6th October 2004, 06:19 PM   #1
rayban68 is offline rayban68  Canada
diyAudio Member
Join Date: Mar 2004
Location: Prince George, BC, Canada
Default P27 Output Voltage

Hello all.

Link to ESP P27 http://www.sound.westhost.com/project27.htm

Schematic is attached.

I mounted my P27 board to an anodized aluminum heatsink using arctic alumina thermal adhesive. There is no conduction between the transistors and the heatsink, but the tabs of all transistors have very little resistance between them. Looking at the schematic, this is ok since they are connected together with the two 0.22 ohm resistors correct?

I powered it up from +/- 12 volts and there was no current draw, fuses were fine, but the amp side of the negative fuse read -7 volts instead of -12 volts. Measured directly at the bench supply it is also -7 volts, when the amplifier is disconnected it is -12 volts. This voltage appears on the output, but there is nothing heating up. I checked for solder problems but don't see any, is there any area that I should be focusing on? I have used NTE semiconductors in place of BC549 & BC559 as that is all I could find, and I managed to put the NTE 123AP in the wrong way for Q4 and Q12, as it is opposite orientation of the transistor that is supposed to be there. I switched those two around, and the same problem occurs. The BD transistors are installed correctly.

Then I upped the voltage to maybe 15 volts and the bench supply hits the current limiting (I think I had it set at around 1-2 amps) and the output transistors heat up right away. Must be a soldering issue somewhere? Again I see no problems, when I look again is there any area I should focus on? I plan to take the multimeter and trace the circuit to test for any problems.

Thanks muchly

Attached Images
File Type: gif p27-f2.gif (13.0 KB, 86 views)
  Reply With Quote


P27 Output VoltageHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
DC Voltage on RCA Output baxtr Parts 7 16th January 2009 10:37 PM
Can An Output Transformer Change A Voltage Amp's Output Impedance From 0.1 To 47 Ohms kelticwizard Everything Else 11 25th March 2007 05:17 AM
eqt with low output voltage marko Car Audio 6 2nd January 2007 12:19 AM
use D1 I/V with voltage output dac poolorpond Pass Labs 6 11th June 2006 07:47 PM
DC voltage on output durxter Chip Amps 20 6th March 2005 06:25 PM

New To Site? Need Help?

All times are GMT. The time now is 11:28 PM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio