AMP HEAD Build Thread

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G-Sun
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Re: AMP HEAD Build Thread

Postby G-Sun » Fri Feb 24, 2012 6:31 pm

Edit: Found the info

mento
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Re: AMP HEAD Build Thread

Postby mento » Mon Mar 05, 2012 6:25 am

Hi there!

I have a question regarding the 10uF bi-polar output caps.

there's no indication how they go in on the pcb. do I fit these the same way like the 100uF ones?

thanks a lot!
matthias

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Joe Malone
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Re: AMP HEAD Build Thread

Postby Joe Malone » Mon Mar 05, 2012 7:50 am

mento wrote:Hi there!

I have a question regarding the 10uF bi-polar output caps.

there's no indication how they go in on the pcb. do I fit these the same way like the 100uF ones?

thanks a lot!
matthias


Hi Matthias

BI Polar or NON polar caps have no polarity so can go in either way around.
Joe :-)
JLM Audio
Capturing Audio without Injury

mento
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Re: AMP HEAD Build Thread

Postby mento » Mon Mar 05, 2012 8:53 am

Joe

thanks for clarification!

matthias

digidesigh
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Re: AMP HEAD Build Thread

Postby digidesigh » Thu Jun 07, 2012 9:51 am

Hi Joe.

I'm very new to DIY ...have only built a few kits from Jaycar and thought this may be a good first project. So far the build thread is understandable, except the points below:

1) I can see there are different options for op amps, and even an option NOT to have one...im wondering what the differences are to the headphone amps performance with the different options.

2) Also what are the differences between using SMPS 48v power supply, VS power + zener's as mentioned in the middle of the thread (or maybe i have misunderstood something)?

3) Which particular SMPS power supply is able to be used from the power supply section of the website, i can see 2 different types. This is the one i can use? i think???
http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=80








Cheers.

Jamil.

kante1603
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Re: AMP HEAD Build Thread

Postby kante1603 » Sat Jun 09, 2012 9:56 pm

Hello Joe,

I hope you´re fine.

Just a short one:On an amphead I´ve built I have a small issue.I did the "mono/mute/on"-mod by implementing a switch as described from you before.
Sadly in mute position as well as in pot position fully ccw (which is the same function,right?) it doesn´t mute completely,there´s still a very low signal audible.
Can you guide me where to look at,maybe lifting the parts prior to the pot?

Thank you in advance,

Udo.

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Re: AMP HEAD Build Thread

Postby Joe Malone » Mon Jun 11, 2012 10:53 am

digidesigh wrote:Hi Joe.

I'm very new to DIY ...have only built a few kits from Jaycar and thought this may be a good first project. So far the build thread is understandable, except the points below:

1) I can see there are different options for op amps, and even an option NOT to have one...im wondering what the differences are to the headphone amps performance with the different options.

The main difference is power rail voltage. OPA2604AP can run on up to +/-24v and NE5532AP can only run up to +/-18v. The OPA2604AP can put out more level on +/-24v but even the NE5532AP can drive all headphones louder than all headphones and ears can handle. Both are very clean very low THD up to there power rail clip point. Amp Head has no problem running into a dead short indefinitely even at full clipped output.

2) Also what are the differences between using SMPS 48v power supply, VS power + zener's as mentioned in the middle of the thread (or maybe i have misunderstood something)?

Any single rail regulated power supply needs zeners fitted to AMP HEAD to make the +/-V. eg 48v = 2 x 24v zeners for +/-24v, 36v = 2 x 18v zeners for +/-18v. If using +/- split rail power supply NO zeners should be fitted.

3) Which particular SMPS power supply is able to be used from the power supply section of the website, i can see 2 different types. This is the one i can use? i think???
http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=80

Any of our 48v SMPS can be used to run the AMP Head kits. But you only need one 48v 15w internal or 48v 25w external to run 2 to 4 AMP HEAD kits. 48v 15w internal SMPS can be turned down with a trim pot to 36v for running +/-18v.
Joe :-)

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Re: AMP HEAD Build Thread

Postby Joe Malone » Mon Jun 11, 2012 11:04 am

kante1603 wrote:Hello Joe,

I hope you´re fine.

Just a short one:On an amphead I´ve built I have a small issue.I did the "mono/mute/on"-mod by implementing a switch as described from you before.
Sadly in mute position as well as in pot position fully ccw (which is the same function,right?) it doesn´t mute completely,there´s still a very low signal audible.
Can you guide me where to look at,maybe lifting the parts prior to the pot?

Thank you in advance,

Udo.


The mute function shorts the +/- audio input together after 2 x 10k resistors together so should mute to a very very low level as long as the 0v ground for the audio input and AMP Head are connected.

Send me a email and I will send you the AMP HEAD schematic so you can see how it works.
Joe :-)

JLM Audio

Capturing Audio without Injury

kante1603
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Re: AMP HEAD Build Thread

Postby kante1603 » Mon Jun 11, 2012 6:30 pm

Joe Malone wrote:The mute function shorts the +/- audio input together after 2 x 10k resistors together so should mute to a very very low level as long as the 0v ground for the audio input and AMP Head are connected.

Send me a email and I will send you the AMP HEAD schematic so you can see how it works.

Hi Joe,

I already have the schematics,you have been so kind to send them after I purchased some ampheads a while ago.
If this is just a ground related issue may be this is the hint:I did AES grounding,I have xlrs for inputs with pin 1 going directly to the chassis.
Better rewire pin1 to psu 0v then (i have an ac/dc psu inside,nearly same build as I did before)?

Thank you in advance,

Udo.

digidesigh
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Re: AMP HEAD Build Thread

Postby digidesigh » Wed Jun 13, 2012 12:15 pm

Hey Udo,

had a look at that website you mentioned which you got your case for this headphone amp, just wondering if you know which model/part number it was? i like the look of that case :D

kante1603
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Re: AMP HEAD Build Thread

Postby kante1603 » Thu Jun 14, 2012 3:42 am

digidesigh wrote:Hey Udo,

had a look at that website you mentioned which you got your case for this headphone amp, just wondering if you know which model/part number it was? i like the look of that case :D

Sure,it´s this one:

Galaxy GX147 124 x 170 x 40 mm

It has an inner useful height of 40mm,don´t swap it with Galaxy maggiorato which has 80mm.

Udo.

digidesigh
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Re: AMP HEAD Build Thread

Postby digidesigh » Thu Jun 14, 2012 11:43 am

excellent, thanks for that man!

digidesigh
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Re: AMP HEAD Build Thread

Postby digidesigh » Thu Jun 14, 2012 12:30 pm

Another question for Joe, and or anyone else who's actually gone through with this project....

I'm still a bit hazy about the Zeners, where will they be fitted exactly? (i am a complete noob at all of this, so bare with me! :P ) The other option is, if i go down the path of using split rail power, is that ok for powering 1 pair of headphones?

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Re: AMP HEAD Build Thread

Postby Joe Malone » Thu Jun 14, 2012 6:53 pm

digidesigh wrote:Another question for Joe, and or anyone else who's actually gone through with this project....

I'm still a bit hazy about the Zeners, where will they be fitted exactly? (i am a complete noob at all of this, so bare with me! :P ) The other option is, if i go down the path of using split rail power, is that ok for powering 1 pair of headphones?


The AMP HEAD has 2 positions for zeners on the PCB makred ZD- and ZD+.

48v 520mA 25w will run up to 4 x AMP head kits with 24v zeners and OPA2604AP.

AC/DC kit can run up to 8 x AMP HEAD kits at either +/-18v or +/-24v with no zeners needed.
Joe :-)

JLM Audio

Capturing Audio without Injury

digidesigh
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Re: AMP HEAD Build Thread

Postby digidesigh » Fri Jun 15, 2012 9:40 am

cool thanks Joe. thats pretty much everything i need to know :D

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