Building A Direct Output Line For An Amp - Page 2 - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

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 30th October 2004, 06:39 AM   #11
Enzo is offline Enzo  United States
diyAudio Member
 
Join Date: Sep 2004
Location: Lansing, Michigan
120 watts was not running through the pot. it was just across something capable of putting that power out. Try a plain old 10k resistor across there as an experiment. I bet it won't burn up. The load determines the power, not the amp. You can run a solid state power amp full out, but if there is no load on it, no power is produced. Even if I had 70V rails, a 10k resistor would still only draw about a half watt. Tube amps have their own issues, so we must load them.

ANy chance the pot arced over? Take it apart and see what the failure mode was.

ALso, when it burned up, was there something connected to it? Or was it just across the output with the wiper unloaded? Point being that if something was connected, there could have been some ground currents finding their way home through the pot.

Another clue would be if it worked OK until the pot was turned close to one end or the other. If some current was allowed to find its way across just the end millimeter of resistive element, it might have been stressed. if the ends of the pot were wired across the amp out and the wiper were turned almost all the way up, and whtever the wiper was connected to was grounded, then the last couple ohms of the pot would be trying to conduct the current of the output stage to ground.
  Reply With Quote
Old 30th October 2004, 06:39 AM   #12
Banned
 
Join Date: Nov 2005
Default Musta been the elctrolytic I ran before the pot....

I think I spiked the voltage with an electrolytic cap I was toying with to cut treble just before feeding the hot lead into the pot.

Anyway I designed my own circuit around the 10 k pot and have AMAZING results.

It goes like this:
Speaker hot lead into I believe a 560 pf cap( I'm certain it's somewhere between 470-560pf....hell it might be as high as a 680! this suckers HUGE) --> 100 k resistor --> 10 k pot --> 1/4 output jack.

THEN I added a tone pot to kill off the intense amount of treble. A 50 K pot with two .1 uf caps. One just wasn't cutting enough and all the other values I toyed with weren't working the way I needed.
.....I've always noticed doubling the same value caps in parrallel will give just a touch more treble cut and do so more gracefully.

ANYWAY, my line out sounds damn near EXACTLY like my custom built/loaded 4x12 cabinet and it get's even better.

The 560 pf and 100 k resistor I used as an input buffer did something very important it turned out.
The 10 k pot at about 50-60% stops increasing volume and increases the signal density. It's not like a gain effect but it's like the signal has more mass.
It's like increasng cabinet resonation!

All in all I'm really happy and this sure beats any of the line out circuits I've found online.

......I think I'll work on my own D.I. box now and come up with a fixed EQ circuit to use in conjunction with my line out circuit which with the way the 10 k pot works to simulate cabinet resonation.

Only involved about 10-12 hours of experimenting today but it paid off. Hopefully someone else can benefit........
  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
Line output as line input transformer? bambadoo Tubes / Valves 7 22nd January 2008 06:44 AM
Direct WM8816 to differential current output DAC panson_hk Chip Amps 4 27th June 2007 05:03 AM
building a line driver fosgate3 Analog Line Level 2 10th May 2007 10:57 PM
Building a non T-line Thor JohnMc Multi-Way 0 14th February 2004 09:58 PM


New To Site? Need Help?

All times are GMT. The time now is 04:33 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