Dear friends,
I am currently building an amplifier chassis for use with M2X and aleph J.
I was wondering if someone could please have a look at the attached design and give me feedback before I order materials. I am not very experienced and not trained.
The design is open source and can be used by anyone. For a quick overview, consult the attached pdf - see below.
If someone would like to replicate the design, the full cad file is available here. However, it is not a stable design as of yet. Also, it requires the builder having access to a 25x30cm heatsink.
My questions are:
1. Anything strange? What would you do different?
2. Are the following items too close to the 500 VA transformer?
Thank you!
Please note that I may not reply immediate to this threat as I am currently not well.
I am currently building an amplifier chassis for use with M2X and aleph J.
I was wondering if someone could please have a look at the attached design and give me feedback before I order materials. I am not very experienced and not trained.
The design is open source and can be used by anyone. For a quick overview, consult the attached pdf - see below.
If someone would like to replicate the design, the full cad file is available here. However, it is not a stable design as of yet. Also, it requires the builder having access to a 25x30cm heatsink.
My questions are:
1. Anything strange? What would you do different?
2. Are the following items too close to the 500 VA transformer?
- the speaker protection board
- the speaker protection board transformer
- the softstart
Thank you!
Please note that I may not reply immediate to this threat as I am currently not well.
Hi Freiheit,
I would place the speaker protection board in the empty space near the speaker binding posts.
Best regards,
Ulf
I would place the speaker protection board in the empty space near the speaker binding posts.
Best regards,
Ulf
+1
A few other things to think about:
- Ventilation holes for the internal amp and power supply spaces (holes/slots on top and bottom of enclosure)
- Fuse for incoming power?
- Integrated fuse/IEC power inlet could be nice and uses standard cables (I saw you want the powercon, just presenting another option)
- cooling for bridge rectifier (if it is mounted on metal and case is vented it is fine)
- If you can bend some flanges on the top and bottom covers the case would be much stronger and some of the clip angles could be eliminated.
Enjoy your project and best wishes for a good new year!
Good advice so far.
For a single channel of M2, this case is enormous.
Why are you using 500VA transformer (so big it may cause problems) when 150VA will be sufficient, and 200VA absolutely more than enough? Bigger is not actually better in this situation.
Add speaker protection only after the amplifier is working properly.
For a single channel of M2, this case is enormous.
Why are you using 500VA transformer (so big it may cause problems) when 150VA will be sufficient, and 200VA absolutely more than enough? Bigger is not actually better in this situation.
Add speaker protection only after the amplifier is working properly.
You definitely want to include a mains fuse holder.
Speaker protection is not really required. It's just another item that could develop faults.
Well if you had $30,000 speakers then maybe, but I have never needed speaker protection and I am dumb, and I don't believe you are dumber than me.
Speaker protection is not really required. It's just another item that could develop faults.
Well if you had $30,000 speakers then maybe, but I have never needed speaker protection and I am dumb, and I don't believe you are dumber than me.
Dear Csample,
thank you for the good feedback. I will
- add ventilation holes for internal amp and power supply
- heatsink for the rectifier. It is already mounted on aluminium, but why not
- add a separate fuseholder right above the AC in (5 x 20 mm 10 A 250 V/AC). The powercon has already arived so I will stick with it for now.
Do you mean like in the attached picture?
Thank you very much for the new year wishes and the good advice. A good year to you too!
thank you for the good feedback. I will
- add ventilation holes for internal amp and power supply
- heatsink for the rectifier. It is already mounted on aluminium, but why not
- add a separate fuseholder right above the AC in (5 x 20 mm 10 A 250 V/AC). The powercon has already arived so I will stick with it for now.
Do you mean like in the attached picture?
Thank you very much for the new year wishes and the good advice. A good year to you too!
Attachments
Dear 6L6,
thank you very much for your feedback.
Yes, I think I have gone overboard with case side and transformer size.
I actually inquired here in the forum before purchasing the transformer but responses were too considerate and polite to prevent me from my folly. I only realised what I had done when I had those heavy things in my hand.
I now have two 500 VA transformers here. Through the following design, I should be able to control the averse effects you imply, or have I overlooked something?
1) EMI is solved by the large case
2) Inrush current is solved by a softstart
3) Hum is solved by a good transformer model
Do you think there is more I can do or would you advise abandoning the 500 VA transformers (in that case I would need to find a new project for them😀)
And yes, will add speaker protection last, thank you!
thank you very much for your feedback.
Yes, I think I have gone overboard with case side and transformer size.
I actually inquired here in the forum before purchasing the transformer but responses were too considerate and polite to prevent me from my folly. I only realised what I had done when I had those heavy things in my hand.
I now have two 500 VA transformers here. Through the following design, I should be able to control the averse effects you imply, or have I overlooked something?
1) EMI is solved by the large case
2) Inrush current is solved by a softstart
3) Hum is solved by a good transformer model
Do you think there is more I can do or would you advise abandoning the 500 VA transformers (in that case I would need to find a new project for them😀)
And yes, will add speaker protection last, thank you!
Another general question to everyone:
I received several reminders above to integrate the fuse holder. While I appreciate and respect this, I was wondering whether one single fuseholder is sufficient.
My understanding is that the fuse should be connected to the live wire. Our local plugs have only two pins, allowing the user to put the plug into the socket anyway he/she likes. That means I never know which side will be a live or a neutral wire. Should I install two fuse holders for this sake?
Thank you!
I received several reminders above to integrate the fuse holder. While I appreciate and respect this, I was wondering whether one single fuseholder is sufficient.
My understanding is that the fuse should be connected to the live wire. Our local plugs have only two pins, allowing the user to put the plug into the socket anyway he/she likes. That means I never know which side will be a live or a neutral wire. Should I install two fuse holders for this sake?
Thank you!
Regarding the flanges, the picture shows what I was thinking - although I would put the flanges inside so they don't show.
Based on the description of the local mains connection I would use two fuses and switch both of the leads. The lack of a safety earth seems troubling.
Houses built in the US prior to ~1960 had polarized two wire mains connections, and now when working on these homes we put GFCI breakers (ground fault circuit interrupt) on such circuits. GFCI breakers will fault out if there is a mismatch in the hot and neutral current, so not as good as a safety earth, but better than nothing. Maybe you already have these? Can anyone else who is used to this system chime in?
Based on the description of the local mains connection I would use two fuses and switch both of the leads. The lack of a safety earth seems troubling.
Houses built in the US prior to ~1960 had polarized two wire mains connections, and now when working on these homes we put GFCI breakers (ground fault circuit interrupt) on such circuits. GFCI breakers will fault out if there is a mismatch in the hot and neutral current, so not as good as a safety earth, but better than nothing. Maybe you already have these? Can anyone else who is used to this system chime in?
ProtectionEarth
@csample
you can (if its your house) ram a steel rod into the ground and bolt some fat wire onto - eh voilá - you have a ProtectionEarth.
back in the 80th, I (not alone) did build a recording studio and all the equipment got an earthwire seperated from the rest of the houses wiring.
@csample
you can (if its your house) ram a steel rod into the ground and bolt some fat wire onto - eh voilá - you have a ProtectionEarth.
back in the 80th, I (not alone) did build a recording studio and all the equipment got an earthwire seperated from the rest of the houses wiring.
Attachments
Last edited:
Parts express has very nice 18 + 18 250 VA
Avel-Lindburg transformers. Would be perfect!
Russellc
I have a stereo fiy Aleph J and a diy stereo M2. When I built them, I used 500 VA Antek transformers.
For a while, I moved one Aleph J board to the M2, and moved one M2 channel to the Aleph J. A heavy switch sent the juice to one board or the other, giving a choice of a M2 mono block or an Aleph J mono block.
Russellc
I ran them for a while like this, but it was over kill for stereo amp moreso in mono block. All I had for in rush was the standard dual CL-60 set up.
There should be safety earth (unless it is indeed an ancient house). It's just that the German plugs fit in both ways. Earth is at the top and the bottom on the picture.
@ Csample, sorry for the misunderstanding. I have not explained well. As Baobei points out, there is safety earth on the sockets, just that plugs fit both ways. And yes, I believe I have GFCI as well.
I will follow your idea and use two fuses and switch both leads. More fuses = more fun. 🙂 Thank you for your feedback!
@ Baobei, thank you very much for the clarification and the picture.
@Russelc, very interesting setup. First time I hear of such a configuration. However, it makes perfect sense. It inspires me to mount both aleph J and M2 boards in my monoblock. That would mean installing a second heatsink in the case. I will tinker around with that! Thank you.
While I belive that 250 VA transformers are more sensible for powering aleph j and m2 monoblocks, I still don't understand why I should not use my 500 VA transformers now...
The equipment fuse protects against fire inside the box. It will do that in *either* wire, except for some unlikely faults.
Go to HiFiEngine and study schematics for recent hi-fi product models sold in your country. See how they are fused.
But two mains fuses is very unlikely.
In general, I feel the box is waaay bigger than necessary. Just one side for heatsinking? There are five more sides that could have at least some heatsink.
Ouch! Number on priority of speaker protection is not to protect speakers per se, but to reduce fire hazard. This is totally independent of the how much you payed for the speakers.
I forget to turn off my FirstWatt F5 when I left the house. While it was home alone, the amp developed a 24 VDC output on the speaker terminals, which was heating up the woofers a bit too much. When I got home, the smell in the house was bad. I was lucky there was no fire, so all I had to do was to get some new woofers and a bunch of speaker protection boards for the F5.
Better safe than sorry!
Ouch! Number on priority of speaker protection is not to protect speakers per se, but to reduce fire hazard. This is totally independent of the how much you payed for the speakers.
I forget to turn off my FirstWatt F5 when I left the house. While it was home alone, the amp developed a 24 VDC output on the speaker terminals, which was heating up the woofers a bit too much. When I got home, the smell in the house was bad. I was lucky there was no fire, so all I had to do was to get some new woofers and a bunch of speaker protection boards for the F5.
Better safe than sorry!
They are just drastic over kill. I used 500 VA (because that is what I used to build the stereo amps, and they were there.) Not sure of what problems 6l6 is referring to, but he generally knows exactly what he is talking about. Perhaps they emit more electro-magnetic junk that causes more hum problems with M2's edcor? Not sure, I know others who have used overkill transformers like this.
On the other hand, they will be good for regular single PS First Watt clones.
There is a thread on the monoblock conversion here somewhere that gave me the idea. "I converted my M2 and Aleph J to monoblocks for $12." or something like that.
Russellc