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Post by Deleted on Mar 28, 2020 18:05:49 GMT
WARNING: This thread could be open for quite a while before I finish it. But I thought I would record my journey here.
Inspired by what I have heard with my Modulus 86 amplifiers, I am thinking about moving up the range. The problem is that these are DIY to some extent. Now I could go the easy route and ask someone like Mr Firebottle to build it for me, but where is the fun in that?
However, there are certain things that scare me, such as if I mess it up, I will have potentially wasted a lot of money, but I think that the amplifier will take a lot of beating. I know someone who has a Benchmark AHB2, and that sounds pretty good. My aim is to beat the performance.
This is going to be a carefully thought out build as I need to keep the cost fairly sensible. Ideally a dual mono build.
I already know what chassis it is going in. The Modushop 4U Dissipante, in black with the 3mm rear and top panels.
I will be spending quite a bit of time on the DIY audio site, looking at builds and taking any good ideas I see from there into my build.
Stage 1, possibly the longest, is to start to source all the parts required. To do that, I need a list and that is what I will be working on next.
Of course, this could well fall flat on it’s arse if the domestic authorities get involved in it.
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Bigman80
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Post by Bigman80 on Mar 28, 2020 18:09:53 GMT
Good man!
If you're gonna do it, do it right and build the biggest lol.
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Post by Deleted on Mar 28, 2020 18:12:19 GMT
I may reduce the output slightly from the maximum spec available.
Amps kicking out 60 degree C in the middle of a hot summer may be an issue.
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Post by Bigman80 on Mar 28, 2020 18:15:40 GMT
I may reduce the output slightly from the maximum spec available. Amps kicking out 60 degree C in the middle of a hot summer may be an issue. Im running mine on 27v SMPS at the minute and will be going to 28v when i get the Torroid, so i can keep the same chassis. |
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Post by sq225917 on Mar 28, 2020 19:20:54 GMT
The Benchmark is literally the benchmark amp to beat these days. Best real world numbers of any power amp.
Class d doesnt count imo as the numbers are skewed by the requirement to use a filter on any test gear producing the numbers. Remove that filter and thd typically goes up by 10db. And their low level linearity is poorer than a decent a/b amp.
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Post by Deleted on Mar 28, 2020 20:33:45 GMT
The Benchmark is good, but very expensive. I am hoping that I can build the 686 for a little over 50% the cost of an AHB2.
Although I have a friend, who is a friend of the designer.
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Post by Deleted on Mar 29, 2020 6:09:29 GMT
Having read a little more, should I fit the speaker protection modules to the amp.
I think it would be a good idea, as if my amp fails, I don’t want it wiping out the speakers.
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Post by Deleted on Mar 29, 2020 6:49:40 GMT
So, I would need this for a standard build:
2 x Modulus-686
1 x Power-686
1 x ISS
2 x Guardian-686 (optional)
1 x Power transformer, 2x25 VAC @ 500 VA
1 x Fused mains inlet
2 x input connector
2 x output connector (Neutrik NL4MP or Neurochrome 5-way binding posts)
1 x power switch
1 x chassis (ex: ModuShop 4U Dissipante - 400 mm deep)
Questions:
If I wanted to go dual mono, then I can cut down the transformers to 2 off 2 x25 VAC @ 350 VA?
Would the Power86 PSU be man enough for one channel?
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Bigman80
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Post by Bigman80 on Mar 29, 2020 8:44:47 GMT
So, I would need this for a standard build: 2 x Modulus-686 1 x Power-686 1 x ISS 2 x Guardian-686 (optional) 1 x Power transformer, 2x25 VAC @ 500 VA 1 x Fused mains inlet 2 x input connector 2 x output connector (Neutrik NL4MP or Neurochrome 5-way binding posts) 1 x power switch 1 x chassis (ex: ModuShop 4U Dissipante - 400 mm deep) Questions: If I wanted to go dual mono, then I can cut down the transformers to 2 off 2 x25 VAC @ 350 VA? Would the Power86 PSU be man enough for one channel? Youd want a minimum 27v 300va transformer for each channel. The power86 isnt big enough either. I do believe tom says somewhere that you can just add bigger caps but I would take that as gospel |
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Post by firebottle on Mar 29, 2020 9:23:59 GMT
Deffo go for dual mono Kev, it made a bid difference with my 86 and 286.
The 86 has toroids and the 286 SMPS, but the improvement was the same.
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Post by Deleted on Mar 29, 2020 9:32:26 GMT
Know anybody who wants a set of FB Monos?
I will contact Tom and see what he suggests as to which PSU PCB I can use for one channel.
Failing that, does anybody have any suggestions of a suitable kit or pre-made PSU PCB I can use?
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Post by Deleted on Mar 29, 2020 21:13:35 GMT
Tom has responded to my numpty questions. You can’t fault his support.
He seems to think a dual mono in a 4U Dissipante, 400 my deep will be a tight fit, and that if I wanted to use the power -86, I will struggle to find caps big enough.
The other suggestion was to use a custom wound transformer, basically combining two separate transformers into 1, if that makes sense - a 4 x 24V transformer. It sounds like a bit of a challenge.
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Post by Deleted on Mar 29, 2020 21:17:04 GMT
Modushop do a 500mm deep 5U chassis. That just looks like total overkill. I don’t think my rack would take a 500mm chassis.
400mm is going to be pushing it....
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Post by antonio on Mar 30, 2020 6:00:51 GMT
Can someone show a link to this Modulus company, I cannot find one anywhere.
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Post by Deleted on Mar 30, 2020 6:19:21 GMT
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Post by Deleted on Mar 30, 2020 8:29:46 GMT
I had a bit of time this morning, so started reading the DIY Audio thread. It looks like Dansaan has built a dual mono into a 4U case, 400mm deep - See here.
To do this, he has used a mezzanine floor in the amp. I assume that I can use a sheet of aluminium for this, and support it well using a stand off in each corner of the mezzanine? |
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Post by Bigman80 on Mar 30, 2020 9:05:10 GMT
I had a bit of time this morning, so started reading the DIY Audio thread. It looks like Dansaan has built a dual mono into a 4U case, 400mm deep - See here.
To do this, he has used a mezzanine floor in the amp. I assume that I can use a sheet of aluminium for this, and support it well using a stand off in each corner of the mezzanine? You can. Good build that isnt it. |
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Post by Deleted on Mar 30, 2020 9:25:46 GMT
Yes. If I can get anywhere close to that, I will be happy.
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Post by Bigman80 on Mar 30, 2020 9:28:44 GMT
Yes. If I can get anywhere close to that, I will be happy. Would be too. Very nice |
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Post by firebottle on Mar 30, 2020 9:45:33 GMT
That's how the 286 is built, with a mezzanine plate holding the psu(s).
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Post by antonio on Mar 30, 2020 10:43:16 GMT
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Post by Bigman80 on Mar 30, 2020 11:03:16 GMT
When Tom builds them, he uses the MeanWell 27v SMPS. His official opinion is that his circuit is so agnostic that it doesn't need a Torroid to maximize performance and that the SMPS is as good. However, it's not. That's been my experience anyway. |
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Post by Deleted on Mar 30, 2020 11:20:44 GMT
Where can I buy a suitable plate (with small vent holes) to fit the PCBs above the traffics?
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Post by firebottle on Mar 30, 2020 11:27:37 GMT
Best thing is to buy a plate from a metal supplier on ebay, get a hole punch and make your own to the size required.
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Post by Deleted on Mar 30, 2020 11:31:47 GMT
Ok, thanks.
The main thing is that it is doable in a 4U chassis.
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Post by Bigman80 on Mar 30, 2020 11:34:51 GMT
Ok, thanks. The main thing is that it is doable in a 4U chassis. You can go to 36v in the 4U case. |
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Post by Deleted on Mar 30, 2020 11:38:27 GMT
I don’t want to stress the components by running at at max capacity, if that makes sense?
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Post by antonio on Mar 30, 2020 12:44:30 GMT
When Tom builds them, he uses the MeanWell 27v SMPS. His official opinion is that his circuit is so agnostic that it doesn't need a Torroid to maximize performance and that the SMPS is as good. However, it's not. That's been my experience anyway. Thank you, I have seen a your post earlier now and you are waiting on a toroid, or I presume 2 if you go mono. What about you Cagey and Alan? |
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Post by sq225917 on Mar 30, 2020 13:18:20 GMT
Looks like that sheet is copper clad board used as the earth plane for the psu and as a traffo shield. I'd stack the rectifier smoother board too.
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Post by Deleted on Mar 30, 2020 13:41:53 GMT
When Tom builds them, he uses the MeanWell 27v SMPS. His official opinion is that his circuit is so agnostic that it doesn't need a Torroid to maximize performance and that the SMPS is as good. However, it's not. That's been my experience anyway. Thank you, I have seen a your post earlier now and you are waiting on a toroid, or I presume 2 if you go mono. What about you Cagey and Alan? At the moment, I plan to get two. |
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