[oporto]

Hi, I am about to order the parts to build the M3.
I have a few questions before I order and any help will he greatly appreciated.
First of all I want to make the M3 to have two outputs. one 3.5mm (1/8) and one 6.35mm (1/4).
The questions is: HOW can I do this? Do I need to buy any extra parts to make this happen? And what would be the basic steps to do it?
 
And how can I have a Continuously variable bass boost and Continuously variable gain? What do I need, how can I do it?
 
That is the most important thing I need to know. But if someone can help me with those other ideas I've got it would be great!
 
 
Well, I thought on changing the OPAMP to a OPA-Moon or OPA-Sun (http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm) but, I dont know if this is possible, and if it is, do I need to do any changes to the M3 or buy more or different parts for it to work with this OPA-Moon or OPA-Sun. And is there any other better or similar OPAMP I can use to replace the original AD8610AR OPAMP? I read that the OPA627 was good but I know nothing about it.
 
I would like to add crossfeed to the M3, the AMB site directs me to http://www.tangentsoft.net/audio/mlxfeed.html and it all looks easy, I just need to buy the Crossfeed and hook it up to the M3 but, how do I do this??? And more importantly, Do I require any different or extra parts for this? because if not I can just do this when the amp is finished as it is an extra.
 
And two simple but significant questions, I am going to build the power supply too, the sigma 11. Is there a problem if I put it in the same enclosure of the M3? I am making my own enclosure out of wood so size is not a problem.
And, what input and output jacks do you guys recommend me?
 
Any suggestions? Recommendations? Ideas?
 
Thanks a lot guys, awesome community. Anything will help.
As soon as my parts arrive I will make a progress diary and upload it with pictures.
 
Oh! And by the way I plan to connect it to a y2 full++ and use it with my AKG Q701.

 

[Yoga Flame]

Nice choice. My M3 has given me many hours of enjoyment.
 
Quote:

First of all I want to make the M3 to have two outputs. one 3.5mm (1/8) and one 6.35mm (1/4).
The questions is: HOW can I do this? Do I need to buy any extra parts to make this happen? And what would be the basic steps to do it?
 

 
The M3 board has two sets of outputs. So you can either wire each of your output jacks separately to the board, or wire them both in parallel to the same output.
 
 
Quote:

And how can I have a Continuously variable bass boost and Continuously variable gain? What do I need, how can I do it?

 

 
It's not possible to do both. One or the other only.
 
 
Quote:

Well, I thought on changing the OPAMP to a OPA-Moon or OPA-Sun (http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm) but, I dont know if this is possible, and if it is, do I need to do any changes to the M3 or buy more or different parts for it to work with this OPA-Moon or OPA-Sun. And is there any other better or similar OPAMP I can use to replace the original AD8610AR OPAMP? I read that the OPA627 was good but I know nothing about it.

 
Never tried those discrete opamps myself. But I expect that they should work as well as they normally would elsewhere. Your biggest challenge would probably be finding a way to fit 3 of them into the enclosure. I use the ADA4627-1 opamp in my M3 and am very happy with it. OPA627 is great too, and doesn't need any adapter, but be careful not to fall for the cheap fakes on eBay. The M3 parts list page has a list of recommended opamps that have been tested to work.
 
It can be fun to experiment with different opamps, but don't worry too much about it. The M3 site says "Each opamp have a sonic character of its own, although the differences are not [that big]..."
 
 
Quote:

I would like to add crossfeed to the M3, the AMB site directs me to http://www.tangentsoft.net/audio/mlxfeed.html and it all looks easy, I just need to buy the Crossfeed and hook it up to the M3 but, how do I do this??? And more importantly, Do I require any different or extra parts for this? because if not I can just do this when the amp is finished as it is an extra.

 

 
Yup. Tangent's crossfeed PCB is very easy to work with. I did mine in a separate enclosure from my M3, but it should be simple to combine it in the same one too. The outputs of the crossfeed go directly to the inputs of the amp. I.e. the crossfeed can go in between the RCA input jacks and the M3 inputs.
 
The M3 has inputs at both the back and front of the board. That's convenient for finding the best position to place your crossfeed board.
 
 
Quote:

And two simple but significant questions, I am going to build the power supply too, the sigma 11. Is there a problem if I put it in the same enclosure of the M3? I am making my own enclosure out of wood so size is not a problem.

 

 
It'll be fine. You can find more details in the "Wiring & ground" section of the M3 site. You won't even need the ground loop breaker since your enclosure is made of wood.
 
 
Good luck!
 

 

[Ntropic]

If you can find it, the Amphenol ACJS-MHD958 is a dual jack unit, with one for 1/8 and one for 1/4 output. It just uses two sets of pins, but it's cool to have it in one unit. Simple enough to wire up too. Mouser doesn't carry it anymore it'd seem, however. They still carry the MHDE though, which is dual 1/4.

 

[oporto]

Quote:

Nice choice. My M3 has given me many hours of enjoyment.
 
 
The M3 board has two sets of outputs. So you can either wire each of your output jacks separately to the board, or wire them both in parallel to the same output.
 
 
 
It's not possible to do both. One or the other only.
 
 
 
Never tried those discrete opamps myself. But I expect that they should work as well as they normally would elsewhere. Your biggest challenge would probably be finding a way to fit 3 of them into the enclosure. I use the ADA4627-1 opamp in my M3 and am very happy with it. OPA627 is great too, and doesn't need any adapter, but be careful not to fall for the cheap fakes on eBay. The M3 parts list page has a list of recommended opamps that have been tested to work.
 
It can be fun to experiment with different opamps, but don't worry too much about it. The M3 site says "Each opamp have a sonic character of its own, although the differences are not [that big]..."
 
 
 
Yup. Tangent's crossfeed PCB is very easy to work with. I did mine in a separate enclosure from my M3, but it should be simple to combine it in the same one too. The outputs of the crossfeed go directly to the inputs of the amp. I.e. the crossfeed can go in between the RCA input jacks and the M3 inputs.
 
The M3 has inputs at both the back and front of the board. That's convenient for finding the best position to place your crossfeed board.
 
 
 
It'll be fine. You can find more details in the "Wiring & ground" section of the M3 site. You won't even need the ground loop breaker since your enclosure is made of wood.
 
 
Good luck!
 

 

Thanks a lot for the quick response guys I will order the parts tomorrow hopefully as I know pretty much everything I needed to know.
 
And Yoga Flame, as for the continuously variable bass boost and gain. Which one do you recommend me? I was thinking on having continuously variable gain and then having two, three or four position switch for the bass boost. Now if that is not possible I will just make it a continuously variable gain. And how do I do that?
 
As for the two outputs, you are saying that it is as simple as identifying the two sets of outputs and connect the two different jacks to it, right?
 
For the crossfeed sounds pretty easy to, I just need to cut the wires connecting the input with the RCA and connect the crossfeed to it.
 



Quote:

If you can find it, the Amphenol ACJS-MHD958 is a dual jack unit, with one for 1/8 and one for 1/4 output. It just uses two sets of pins, but it's cool to have it in one unit. Simple enough to wire up too. Mouser doesn't carry it anymore it'd seem, however. They still carry the MHDE though, which is dual 1/4.

 
Thank you, I will have a look at it : )

 

[oporto]

I forgot to ask, I have read that some people use 430uF in their M3 and it makes a difference. If I do this, I need to replace the original 330 uF 50V Aluminum Cap for a 430uF one?

 

[bada bing]

 
Quote:

I forgot to ask, I have read that some people use 430uF in their M3 and it makes a difference. If I do this, I need to replace the original 330 uF 50V Aluminum Cap for a 430uF one?

You mean 470uF maybe ? The "C7" power rail capacitors are in a parallel bank and the total capacitance is the sum of how ever many caps you've installed. The total is what is important, not the values of the individual caps. You don't have to populate all c7 locations. Don't go cheap on the caps and don't install more capacitance than is needed, between 2000uF and 3000uF total is plenty. I have 6 470uF elna silmic II's (digikey is an Elna vendor) in mine.
 
A couple of observations on building a M3:
The M3 is a bit more prone to picking up hum than most designs. Don't finalize mounting and wiring of the transformer, boards and input jacks until you've temporariliy positioned them and listened. Building a hum free, single box M3 takes a bit of tweaking of the wiring.
Get the basic amp up and running before playing with variable gain, bass boost and crossfeed.
My personal opinion is that the basic amp with a mild bass boost that can be jumpered out is the best configuration. Crossfeed is interesting to play with, but I pulled the crossfeed board out after playing with it for a while.
Read Tangent's write up on the PPA for more insight into some of your M3 questions. http://tangentsoft.net/audio/ppa/amp2/ . The PPAv2 is very similar to the M3 and Tangent's explanations about issues like capacitor choices, bass boost, etc. are useful for a more detailed understanding of the M3. As an off topic comment, I just noticed that Tangent doesn't offer PPAv2 boards anymore. Bummer

, I liked the PPAv2 very much, in some ways it surpassed the M3, IMO. 

 

[oporto]

I know, its just that I want to order the parts together to same money from the shipping costs. And the crossfeed can wait. I already ordered the parts from amb. Im just missing the parts from mouser. Because of the sigma11 and the jacks which I dont know which ones to use. I got this one for the 1/4 output:
http://au.mouser.com/Search/ProductDetail.aspx?R=NJ3FP6C-Bvirtualkey56810000virtualkey568-NJ3FP6C-B
 
but cant decide which one of these for the 1/8 output:
http://au.mouser.com/ProductDetail/Switchcraft/PC-142AX/?qs=sGAEpiMZZMv0W4pxf2HiVyduI9684dfYH5kKfsPKfCE%3d
http://au.mouser.com/ProductDetail/Switchcraft/142AX/?qs=sGAEpiMZZMv0W4pxf2HiV6YB0RWJpyofE38K%252b3JXaQk%3d
http://au.mouser.com/ProductDetail/Kycon/STX-35332-3N-TR/?qs=sGAEpiMZZMv0W4pxf2HiV7doqFvEwh0kwtvf6jvFThY%3d
 
I just want the best available, any ideas for the 1/8 output?
 
And thanks for your help : )

 

[amb]

Quote:

Originally Posted by oporto /img/forum/go_quote.gif
 
but cant decide which one of these for the 1/8 output:
http://au.mouser.com/ProductDetail/Switchcraft/PC-142AX/?qs=sGAEpiMZZMv0W4pxf2HiVyduI9684dfYH5kKfsPKfCE%3d
http://au.mouser.com/ProductDetail/Switchcraft/142AX/?qs=sGAEpiMZZMv0W4pxf2HiV6YB0RWJpyofE38K%252b3JXaQk%3d
http://au.mouser.com/ProductDetail/Kycon/STX-35332-3N-TR/?qs=sGAEpiMZZMv0W4pxf2HiV7doqFvEwh0kwtvf6jvFThY%3d

 
The first and third ones are PCB-mount.  Only the second one is for panel-mounting.  It's ok to use if your front panel is electrically non-conductive so that the sleeve contact (which is also the threaded mount bushing) does not short to chassis ground.  Otherwise you need to find an isolated jack.
 
 

 

[Willakan]

I would advise against using any of AudioGd's discrete opamps. Their only notable characteristics are their expense, very high distortion and poor linearity. The recommended IC opamps for the M^3 are superior in virtually every respect.
 
Measurements source: http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf

 

[oporto]

 
Quote:

I would advise against using any of AudioGd's discrete opamps. Their only notable characteristics are their expense, very high distortion and poor linearity. The recommended IC opamps for the M^3 are superior in virtually every respect.
 
Measurements source: http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf

Thanks for the advice, I havent ordered them yet as I planned on getting them later on as an upgrade. I im giong for the OPA627 for now.

 

[oporto]

Quote:

 


Thanks for the advice, I havent ordered them yet as I planned on getting them later on as an upgrade. I im giong for the OPA627 for now.

 


Quote:

I would advise against using any of AudioGd's discrete opamps. Their only notable characteristics are their expense, very high distortion and poor linearity. The recommended IC opamps for the M^3 are superior in virtually every respect.
 
Measurements source: http://www.sg-acoustics.ch/analogue_audio/ic_opamps/pdf/opamp_distortion.pdf

 


Quote:

 
The first and third ones are PCB-mount.  Only the second one is for panel-mounting.  It's ok to use if your front panel is electrically non-conductive so that the sleeve contact (which is also the threaded mount bushing) does not short to chassis ground.  Otherwise you need to find an isolated jack.
 
 

 


Quote:

I know, its just that I want to order the parts together to same money from the shipping costs. And the crossfeed can wait. I already ordered the parts from amb. Im just missing the parts from mouser. Because of the sigma11 and the jacks which I dont know which ones to use. I got this one for the 1/4 output:
http://au.mouser.com/Search/ProductDetail.aspx?R=NJ3FP6C-Bvirtualkey56810000virtualkey568-NJ3FP6C-B
 
but cant decide which one of these for the 1/8 output:
http://au.mouser.com/ProductDetail/Switchcraft/PC-142AX/?qs=sGAEpiMZZMv0W4pxf2HiVyduI9684dfYH5kKfsPKfCE%3d
http://au.mouser.com/ProductDetail/Switchcraft/142AX/?qs=sGAEpiMZZMv0W4pxf2HiV6YB0RWJpyofE38K%252b3JXaQk%3d
http://au.mouser.com/ProductDetail/Kycon/STX-35332-3N-TR/?qs=sGAEpiMZZMv0W4pxf2HiV7doqFvEwh0kwtvf6jvFThY%3d
 
I just want the best available, any ideas for the 1/8 output?
 
And thanks for your help : )

 


Quote:

 


You mean 470uF maybe ? The "C7" power rail capacitors are in a parallel bank and the total capacitance is the sum of how ever many caps you've installed. The total is what is important, not the values of the individual caps. You don't have to populate all c7 locations. Don't go cheap on the caps and don't install more capacitance than is needed, between 2000uF and 3000uF total is plenty. I have 6 470uF elna silmic II's (digikey is an Elna vendor) in mine.
 
A couple of observations on building a M3:
The M3 is a bit more prone to picking up hum than most designs. Don't finalize mounting and wiring of the transformer, boards and input jacks until you've temporariliy positioned them and listened. Building a hum free, single box M3 takes a bit of tweaking of the wiring.
Get the basic amp up and running before playing with variable gain, bass boost and crossfeed.
My personal opinion is that the basic amp with a mild bass boost that can be jumpered out is the best configuration. Crossfeed is interesting to play with, but I pulled the crossfeed board out after playing with it for a while.
Read Tangent's write up on the PPA for more insight into some of your M3 questions. http://tangentsoft.net/audio/ppa/amp2/ . The PPAv2 is very similar to the M3 and Tangent's explanations about issues like capacitor choices, bass boost, etc. are useful for a more detailed understanding of the M3. As an off topic comment, I just noticed that Tangent doesn't offer PPAv2 boards anymore. Bummer

, I liked the PPAv2 very much, in some ways it surpassed the M3, IMO. 

 


Quote:

I forgot to ask, I have read that some people use 430uF in their M3 and it makes a difference. If I do this, I need to replace the original 330 uF 50V Aluminum Cap for a 430uF one?

 


Quote:

 

Thanks a lot for the quick response guys I will order the parts tomorrow hopefully as I know pretty much everything I needed to know.
 
And Yoga Flame, as for the continuously variable bass boost and gain. Which one do you recommend me? I was thinking on having continuously variable gain and then having two, three or four position switch for the bass boost. Now if that is not possible I will just make it a continuously variable gain. And how do I do that?
 
As for the two outputs, you are saying that it is as simple as identifying the two sets of outputs and connect the two different jacks to it, right?
 
For the crossfeed sounds pretty easy to, I just need to cut the wires connecting the input with the RCA and connect the crossfeed to it.
 


 
Thank you, I will have a look at it : )

 


Quote:

If you can find it, the Amphenol ACJS-MHD958 is a dual jack unit, with one for 1/8 and one for 1/4 output. It just uses two sets of pins, but it's cool to have it in one unit. Simple enough to wire up too. Mouser doesn't carry it anymore it'd seem, however. They still carry the MHDE though, which is dual 1/4.

 


Quote:

Nice choice. My M3 has given me many hours of enjoyment.
 
 
The M3 board has two sets of outputs. So you can either wire each of your output jacks separately to the board, or wire them both in parallel to the same output.
 
 
 
It's not possible to do both. One or the other only.
 
 
 
Never tried those discrete opamps myself. But I expect that they should work as well as they normally would elsewhere. Your biggest challenge would probably be finding a way to fit 3 of them into the enclosure. I use the ADA4627-1 opamp in my M3 and am very happy with it. OPA627 is great too, and doesn't need any adapter, but be careful not to fall for the cheap fakes on eBay. The M3 parts list page has a list of recommended opamps that have been tested to work.
 
It can be fun to experiment with different opamps, but don't worry too much about it. The M3 site says "Each opamp have a sonic character of its own, although the differences are not [that big]..."
 
 
 
Yup. Tangent's crossfeed PCB is very easy to work with. I did mine in a separate enclosure from my M3, but it should be simple to combine it in the same one too. The outputs of the crossfeed go directly to the inputs of the amp. I.e. the crossfeed can go in between the RCA input jacks and the M3 inputs.
 
The M3 has inputs at both the back and front of the board. That's convenient for finding the best position to place your crossfeed board.
 
 
 
It'll be fine. You can find more details in the "Wiring & ground" section of the M3 site. You won't even need the ground loop breaker since your enclosure is made of wood.
 
 
Good luck!
 

 


Quote:

Hi, I am about to order the parts to build the M3.
I have a few questions before I order and any help will he greatly appreciated.
First of all I want to make the M3 to have two outputs. one 3.5mm (1/8) and one 6.35mm (1/4).
The questions is: HOW can I do this? Do I need to buy any extra parts to make this happen? And what would be the basic steps to do it?
 
And how can I have a Continuously variable bass boost and Continuously variable gain? What do I need, how can I do it?
 
That is the most important thing I need to know. But if someone can help me with those other ideas I've got it would be great!
 
 
Well, I thought on changing the OPAMP to a OPA-Moon or OPA-Sun (http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm) but, I dont know if this is possible, and if it is, do I need to do any changes to the M3 or buy more or different parts for it to work with this OPA-Moon or OPA-Sun. And is there any other better or similar OPAMP I can use to replace the original AD8610AR OPAMP? I read that the OPA627 was good but I know nothing about it.
 
I would like to add crossfeed to the M3, the AMB site directs me to http://www.tangentsoft.net/audio/mlxfeed.html and it all looks easy, I just need to buy the Crossfeed and hook it up to the M3 but, how do I do this??? And more importantly, Do I require any different or extra parts for this? because if not I can just do this when the amp is finished as it is an extra.
 
And two simple but significant questions, I am going to build the power supply too, the sigma 11. Is there a problem if I put it in the same enclosure of the M3? I am making my own enclosure out of wood so size is not a problem.
And, what input and output jacks do you guys recommend me?
 
Any suggestions? Recommendations? Ideas?
 
Thanks a lot guys, awesome community. Anything will help.
As soon as my parts arrive I will make a progress diary and upload it with pictures.
 
Oh! And by the way I plan to connect it to a y2 full++ and use it with my AKG Q701.

 
 
 
 
 
 

It has began!!!! Finally I managed to get every part and every tool I needed for the construccion of the M^3 and two Sigma11!
Here is the link to the construction/building threat I just made, I will post my progress regularly.
 
http://www.head-fi.org/t/581911/building-my-m-3-and-two-sigma11#post_7915554
 
And again, thank you guys!