how to compensate diffrence in amp gains in 3-amp system

futiboho · 14th October 2004, 10:58 AM

I will appreciate your advise on what are the practical steps to do this task. The amps I use have gains of 63 (The END, LC Audio) and 32 (Thel Accusound). I know what to do in principle but am interested on details, e.g.:

1) what signal I have to use at the input of the active XO (from what source, e.g. test CD, white noise...?) so that the three ways should pass identical levels of output and then I can measure the V at the amp outputs, to be made (the volts) equal for each amp via adjusting the XO output trims.

2) Are there alternatives? (I don't have an osciloscope and hope the adjustment could be done with what I have (multimeter, test CD, ears...)

many thanks for your insights!

richie00boy · 14th October 2004, 11:29 AM

Set the XO aside and just feed each input with a 1 kHz sine wave and measure the output voltage with a volt meter. Adjust each amp level control to get the same reading on the meter.

futiboho · 14th October 2004, 02:15 PM

Thanks. I was talking about a signal through the XO because my amps do not have volume controls while the XO has trimers at its output. Any idea how to set these trimer pots?

richie00boy · 15th October 2004, 07:27 AM

With your ears. It would be pointless setting the voltage at the speaker terminals all the same anyway as the different drivers will have different sensitivities and efficiencies.

Upupa Epops · 15th October 2004, 08:04 AM

Is not good to use different amps for active crossover. By my experiences best results are only with the same amps.

futiboho · 15th October 2004, 08:36 AM

Upupa, I see your point but disagree. My research has made me believe that you have to combine amps that are particularly good at the respective frequency ranges and this is what I did.

AndrewT · 15th October 2004, 08:53 AM

I agree, select the amps that best suit the frequency range and accept a bit of resetting to equalise volume due to different gains and sensitivities. In the extreme you might use tubes for the treble, class A solid state for mid & class AB for the bass. Not just differnt makes but a whole different philosophy. The problem might be finding a set of matching (nice sounding) amps to experiment with.

Upupa Epops · 15th October 2004, 09:06 AM

I'm standing along by my words

, but I don't take your opinions - judgement will be only our common listening, which is probably rather notreal

.

14th October 2004, 10:58 AM	#1
futiboho diyAudio Member Join Date: Oct 2004	how to compensate diffrence in amp gains in 3-amp system I will appreciate your advise on what are the practical steps to do this task. The amps I use have gains of 63 (The END, LC Audio) and 32 (Thel Accusound). I know what to do in principle but am interested on details, e.g.: 1) what signal I have to use at the input of the active XO (from what source, e.g. test CD, white noise...?) so that the three ways should pass identical levels of output and then I can measure the V at the amp outputs, to be made (the volts) equal for each amp via adjusting the XO output trims. 2) Are there alternatives? (I don't have an osciloscope and hope the adjustment could be done with what I have (multimeter, test CD, ears...) many thanks for your insights!

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Different Gains Correction (VAS solution)	Stee	Solid State	2	8th September 2008 02:49 AM
Follow up to cap sleeve thread,Wire color makes a diffrence!!	CryingDragon	Parts	48	24th April 2008 02:07 AM
Opamps and Gains	mudihan	Digital Source	14	18th July 2006 02:42 PM
gains with lm3886	Doovieman	Chip Amps	6	13th July 2005 05:04 AM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

14th October 2004, 11:29 AM	#2
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	Set the XO aside and just feed each input with a 1 kHz sine wave and measure the output voltage with a volt meter. Adjust each amp level control to get the same reading on the meter.

14th October 2004, 02:15 PM	#3
futiboho diyAudio Member Join Date: Oct 2004	Thanks. I was talking about a signal through the XO because my amps do not have volume controls while the XO has trimers at its output. Any idea how to set these trimer pots?

15th October 2004, 07:27 AM	#4
richie00boy Did it Himself diyAudio Member Join Date: Nov 2003 Location: Gloucestershire, England, UK	With your ears. It would be pointless setting the voltage at the speaker terminals all the same anyway as the different drivers will have different sensitivities and efficiencies.

15th October 2004, 08:04 AM	#5
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	Is not good to use different amps for active crossover. By my experiences best results are only with the same amps.

15th October 2004, 08:36 AM	#6
futiboho diyAudio Member Join Date: Oct 2004	Upupa, I see your point but disagree. My research has made me believe that you have to combine amps that are particularly good at the respective frequency ranges and this is what I did.

15th October 2004, 08:53 AM	#7
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	I agree, select the amps that best suit the frequency range and accept a bit of resetting to equalise volume due to different gains and sensitivities. In the extreme you might use tubes for the treble, class A solid state for mid & class AB for the bass. Not just differnt makes but a whole different philosophy. The problem might be finding a set of matching (nice sounding) amps to experiment with.

15th October 2004, 09:06 AM	#8
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	I'm standing along by my words , but I don't take your opinions - judgement will be only our common listening, which is probably rather notreal .

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)