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Post by Deleted on Oct 31, 2020 10:33:10 GMT
After hearing the Modulus-86 amps in my system, and upgrading my speakers to Triangle Antal EZ, I decided (and was advised) that I really need more power to get the best out of them.
As this is my first DIY build, I decided to dip my toe in the water with a Guardian 686 build, which I finished some time ago, but only recently tested it. To my surprise, it worked...
So I am now planning the next stage of my build, and have ordered two Power 686 PCBs to build during my latest confinement. They should be here next week, but I need to order the parts to build them.
So, I have started this thread for a convenient place for help and advice as I plod my way through this build.
I plan to build a dual mono version, with each channel being powered by a 2 x 25V 400VA transformer, so I am going to need a case with some serious real estate.
I will probably use the Modushop Dissipante case recommended, but I am torn between the 4U and 5U case. After all, why not have the extra 45mm available? I am thinking that I will need the 400mm deep case to fit everything in. So, this is probably going to end up as being a two man lift to move it around.
Other bits I need are:
2 x Modulus 686 amp boards
A soft start to minimise in-rush current (one, or two?)
2 x transformers (2 x 25V, 400 VA)
My first question is about the transformers. Without getting too silly, what is a decent transformer for a Power amp? I was thinking Toroidy Audio grade, but are they really required? Will it make a difference above the normal transformers?
I plan to fit RCA connectors, as well as balanced inputs. So I will also need to decide on what sockets to fit, without going over the top.
There is also the speaker binding posts and the IEC inlet to spec.
I am going to wire the internals with OCC copper cable.
I am sure there will be more as I progress.
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Post by firebottle on Oct 31, 2020 11:11:30 GMT
Toroidy Audio grade are certainly worth it as they are silent. If you go for another make specify an interwinding screen, usually a cost add on.
I think it is included in the Toroidy.
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Post by Deleted on Oct 31, 2020 11:14:29 GMT
Thanks Alan. Toroidy Audio grade it is then.
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Bigman80
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Post by Bigman80 on Oct 31, 2020 11:14:59 GMT
After hearing the Modulus-86 amps in my system, and upgrading my speakers to Triangle Antal EZ, I decided (and was advised) that I really need more power to get the best out of them. As this is my first DIY build, I decided to dip my toe in the water with a Guardian 686 build, which I finished some time ago, but only recently tested it. To my surprise, it worked... So I am now planning the next stage of my build, and have ordered two Power 686 PCBs to build during my latest confinement. They should be here next week, but I need to order the parts to build them. So, I have started this thread for a convenient place for help and advice as I plod my way through this build. I plan to build a dual mono version, with each channel being powered by a 2 x 25V 400VA transformer, so I am going to need a case with some serious real estate. I will probably use the Modushop Dissipante case recommended, but I am torn between the 4U and 5U case. After all, why not have the extra 45mm available? I am thinking that I will need the 400mm deep case to fit everything in. So, this is probably going to end up as being a two man lift to move it around. Other bits I need are: 2 x Modulus 686 amp boards A soft start to minimise in-rush current (one, or two?) 2 x transformers (2 x 25V, 400 VA) My first question is about the transformers. Without getting too silly, what is a decent transformer for a Power amp? I was thinking Toroidy Audio grade, but are they really required? Will it make a difference above the normal transformers? I plan to fit RCA connectors, as well as balanced inputs. So I will also need to decide on what sockets to fit, without going over the top. There is also the speaker binding posts and the IEC inlet to spec. I am going to wire the internals with OCC copper cable. I am sure there will be more as I progress. My 2p: Get the best Traffo you can and make it 600VA.... Toroidy is where I went for mine and it's perfect. CMC pure copper sockets (yes, they are!) CMC Pure copper Binding posts (again, they really are) You are looking at £100 in connectors there but it's well worth it IMO. Get a decent size case...4U probably a minimum. Room to work and room to breathe. If your 686 boards come with connectors for the signal, take them off and solder to the PCB or better still, ask Tom not to fit them at all. Get a MEATY power switch ... |
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Post by Deleted on Oct 31, 2020 11:18:42 GMT
How meaty is meaty?
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Bigman80
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Post by Bigman80 on Oct 31, 2020 11:21:12 GMT
Think industrial power switch lol I'll find a link... hang on |
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Post by macca on Oct 31, 2020 11:26:30 GMT
Dpn't forget that the 'power on' LED should be orange or red (yellow is also acceptable). So many DIYers and manufacturers get that wrong and it's far and away the most important thing.
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Post by Deleted on Oct 31, 2020 11:36:32 GMT
I might fit a blue one just to annoy Macca.  |
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Bigman80
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Post by Bigman80 on Oct 31, 2020 11:38:57 GMT
Dpn't forget that the 'power on' LED should be orange or red (yellow is also acceptable). So many DIYers and manufacturers get that wrong and it's far and away the most important thing. Hahahaha, I'm into white ones at the minute |
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Post by Deleted on Oct 31, 2020 11:40:19 GMT
The Audiophonics orange one I fitted to the FB Monos is really discrete.
Only rated at 5A though.
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Bigman80
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Post by Bigman80 on Oct 31, 2020 12:24:02 GMT
The Audiophonics orange one I fitted to the FB Monos is really discrete. Only rated at 5A though. I'd want 10A |
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Post by sq225917 on Oct 31, 2020 14:32:44 GMT
24v not 25 for the traffo then you have a little wriggle room for high mains. Also worth considering what diodes to use on the psu, im not sure what format the boards take, but if its 4x single diodes then use qspeed diodes, there's none quieter apart from an active bridge, and if your thinking of active bridge then go for 22v traffos as there's no forward diode loss. For soft start go for a single, with the traffos paired into the output pins. www.audiophonics.fr/en/softstart-protection/connex-power-soft-start-v4-power-on-and-delay-soft-start-board-for-amplifier-p-10298.htmlIts 16 amp capable and has low voltage output drive for a sensibly rated on/off switch. Its what I used in my bridged mono modulus 86p builds, (effectively dual mono 486s, if such a thing existed). |
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Post by Deleted on Nov 1, 2020 10:59:44 GMT
Also worth considering what diodes to use on the psu, im not sure what format the boards take, but if its 4x single diodes then use qspeed diodes, there's none quieter apart from an active bridge, and if your thinking of active bridge then go for 22v traffos as there's no forward diode loss. It uses STBR3012-WY high voltage rectifiers. With my limited knowledge I struggled to find a QSpeed alternative. After struggling all weekend with the Mouser site, all parts have finally been ordered as per the BoM that Tom recommends. The Power 686 builds start next week. |
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Post by Deleted on Nov 3, 2020 5:27:53 GMT
Looks like it was worth waiting.... link |
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Post by sq225917 on Nov 3, 2020 19:10:16 GMT
Ooh, cool. Does that make them better than the Benchmark amp? Seriously, the idea that you can diy the best measuring class A/ B amps ever made for about 2k is just crazy.
Imagine what this performance and power would have cost from a turnkey brand 15 years ago?
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Post by Deleted on Nov 3, 2020 19:15:00 GMT
I have no idea if they will be better.
The advantage of this amp is that I can build it it by bit, spreading the cost as I go.
It should be seriously good when finished.
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Post by Deleted on Nov 3, 2020 21:57:04 GMT
The Modulus-686 delivers 240 W into 8 Ω at 0.00028% (-111 dBc) THD+N
The Benchmark AHB2
< 0.0003 % THD+N at full rated power, 20 Hz to 20 kHz
100 Watts per channel into 8 Ohms, both channels driven
130 Watts per channel into 6 Ohms, both channels driven
190 Watts per channel into 4 Ohms, both channels driven
240 Watts per channel into 3 Ohms, both channels driven
200 Watts into 16 Ohms, bridged mono
380 Watts into 8 Ohms, bridged mono
480 Watts into 6 Ohms, bridged mono
So I reckon the 686 will have it, as the Benchmark is probably 0.00029% but at this level of performance, who cares?
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Post by macca on Nov 3, 2020 22:16:37 GMT
It certainly got the numbers.
What will be the pre-amp?
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Bigman80
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Post by Bigman80 on Nov 3, 2020 22:35:51 GMT
It certainly got the numbers. What will be the pre-amp? Firebottle KIN with Alps blue I believe.............he needs one of my biscuit tins with an AWM Stepped Attenuator in it!! You can have McVities or Scottish Shortbread.....any other brand is extra as I have to buy the tin first 🤣 |
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Post by Deleted on Nov 4, 2020 1:13:44 GMT
At the moment, Oli is correct, although I plan on upgrading the volume pot.
I have no plans for a pre-amp change, even if it was a quality street to go down with a bit of a celebration.
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Bigman80
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Post by Bigman80 on Nov 4, 2020 5:26:36 GMT
Not even for my "Jacobs" special? Lol
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Post by Deleted on Nov 4, 2020 6:58:25 GMT
It is Shortbread or nothing in my book, with a typically seasonal background.
Out of interest, why 600VA fornthe traffos? Is 400 or 500VA not enough?
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Bigman80
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Post by Bigman80 on Nov 4, 2020 8:32:08 GMT
It is Shortbread or nothing in my book, with a typically seasonal background. Out of interest, why 600VA fornthe traffos? Is 400 or 500VA not enough? I just like POWER lol Dunno, Angus told me to do it |
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Post by Deleted on Nov 4, 2020 9:19:08 GMT
It certainly got the numbers. What will be the pre-amp? I can also use a Graham Slee Majestic. |
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Bigman80
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Post by Bigman80 on Nov 4, 2020 10:32:45 GMT
@cageyh
The 600va was due to having one transformer in the case rather than two, and it having 4 individual secondaries
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Post by Deleted on Nov 4, 2020 10:56:35 GMT
Ah, thanks. So two off 2x24V 400 VA should be fine then?
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Bigman80
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Post by Bigman80 on Nov 4, 2020 11:13:10 GMT
Ah, thanks. So two off 2x24V 400 VA should be fine then? Probably...may want to get sq, or Alan to confirm....I'm only a bodger after all lol |
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Post by Deleted on Nov 4, 2020 11:21:27 GMT
Tom suggested the 400VA. Simon suggested to drop from 2 x 25V to 2 x 24V.
As it is lunchtime, and I am eating at my desk, how do the Modushop modifications work?
I am looking for an engraved front panel that is quite discreet (NEUROCHROME :: MODULUS 686) with a hole for a BLUE power switch.
And on the back, the standard holes + RCA sockets for a 686. I assume that there is a file available somewhere?
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Bigman80
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Post by Bigman80 on Nov 4, 2020 14:59:32 GMT
Tom suggested the 400VA. Simon suggested to drop from 2 x 25V to 2 x 24V. As it is lunchtime, and I am eating at my desk, how do the Modushop modifications work? I am looking for an engraved front panel that is quite discreet (NEUROCHROME :: MODULUS 686) with a hole for a BLUE power switch. And on the back, the standard holes + RCA sockets for a 686. I assume that there is a file available somewhere? If you email Tom, he has a file you can give directly to Modushop. It has all the details you need and they will make the case to its specs |
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Post by sq225917 on Nov 4, 2020 20:03:39 GMT
The 24v traffo is based on UK mains, 216-252v legal range. Were we actually guaranteed 240v 25v would fine, but we aint. Better safe than clipped.
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