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gainphile

Class-D 8-channel amplifier build

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A quick update: I installed the second SMPS so that each board is powered separately.

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Looks very tidy!

Have you noticed any improvement with the extra headroom in the PSU?

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So that is 8 x 40w? Amazing what you can get now. Good thing you got the 3RU box!

Ever considered speakon connectors? Easy quick swap overs, no mistakes and you could in fact end up with just two connectors ... or 4. You can get them cheap on ebay. Worth considering. (I've screwed a few too many binding post terminals!)

Edited by Paul Spencer

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Looks very tidy!

Have you noticed any improvement with the extra headroom in the PSU?

Sonically they are similar actually. It may be just a waste of power :)

Calculating the power requirements from my dipoles, they don't really need much to drive them to xmax. Plus the ears & mrs gave up earlier ...

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So that is 8 x 40w? Amazing what you can get now. Good thing you got the 3RU box!

Ever considered speakon connectors? Easy quick swap overs, no mistakes and you could in fact end up with just two connectors ... or 4. You can get them cheap on ebay. Worth considering. (I've screwed a few too many binding post terminals!)

Yes, and at 4ohm they are 8x100w :)

I've been toying with the Speakon idea actually... But banana plugs may be even cheaper.

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I purchased the exact module just a short while ago and have been comparing the sound to my existing TAS5630 based class D modules from Sinewave with integrated smps. Noise floor is lower than the Sinewave modules which produce an audible hiss with buzzyness if you put your ear up close.

First impressions were of a delicate articulate sound, slightly dry in nature. Turn them up at loud and I'm afraid it all goes to pieces. The high powered TAS5630 has a slight edge to the upper midrange but overall presents a fatter fuller sound which remained effortless and consistent at high volumes. I am not doubting that to most people these amps sound great but I believe the power handling figures especially where high distortion kicks in is grossly overstated. It actually sound as though they're only clean out to about 30watts rms into 8 ohs. Every time I swap the amps over I find myself leaning towards the Sure amps but eventually come to prefer the meatier quality of the Sinewave amps. I'm using the Meanwell 27 vdc power supply ont he Sure amp which I've cranked up to 32 volts.

There's some cruddy components in there an I'm thinking of ditching the weird hipass filter caps on the input stage. I've heard that this make a significant difference.

Cheers, and happy listening.

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Interesting to hear your comments. I have a pair of Sinewave modules for my future surrounds, which I'm not currently using. I've also looked at the Sure modules. Not surprising if they have inflated the specs. The Sinewave specs look a bit optimistic and they seem to spec it with high distortion. Would be a non issue in my case since I'd be running ultra sensitive active speakers where 1w shatters glass!

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Is that one of the jaycar 19" rack cases? Was looking at using one myself for a similar setup.

They are Altronics one. Cheaper and better looking than Jaycar's

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Hi Gainphile,

Great looking amp!

I'm considering similar to power my 4x Eminence Beta 15a's, also in open baffle.

Could I please ask, How much difference was there between using one power supply vs two?

The reason I ask is I'm considering whether to go with a 4x100W TK2050 and use one channel per woofer (with one power supply as you have here) or to go with 2 2x100W TK2050 with a power supply each.

I'm not looking to play super low or loud, but I just don't want the amp to be struggling.

Thanks,

James.

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I could not find difference between 1 or 2 PSU. In fact I took off the second one and used it for another amp project.

What is critical though, is that 24v is not enough and the whole amp may clip under heavy passages (!). Adjust the SMPS to 26v and all good. Not more though, as the max. adjustable voltage is 26.4v

I'd go with one amp per woofer :)

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Thanks for the reply.

This may be a pretty amateur question, but is adjusting the PS to 26V easy? I'm looking at the same one you've mentioned here.

When you say one amp per woofer, do you mean one amp per side, or should I be looking at 4x the 2 channel TK2050's?

Thanks so much for your help here.

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Thanks for the reply.

This may be a pretty amateur question, but is adjusting the PS to 26V easy? I'm looking at the same one you've mentioned here.

When you say one amp per woofer, do you mean one amp per side, or should I be looking at 4x the 2 channel TK2050's?

Thanks so much for your help here.

Very easy but you need a multimeter (There's $9 good ones at Jaycar). Just twist the adjustment screw near SMPS's output. They are set at 24v as default.

How amateur are you :) ... just be careful with the 220v live power input. Cover them with cellotapes first !!!

I don't know about 2x TK2050 as i don't have them. But the 4x one is good and simple.

In fact now there's 150w and 300w versions. Those are really tempting although might not really needed.

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hi gainphile,

i have sds-470 from classdaudio coming, checked the altronics, their 19" cases are very good.

i wonder who can do stamping/machining for the neutriks holes (XLR & Speakon), do u drill urself?

cheers

henry

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It took me the longest of time to drill them holes ! Using one of those conical grinder.

And for the AC power I use jigsaw !!

Most painful exercise and all the metal bits everywhere on the carpet !!

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ok, i can feel ur pain :D ,

actually i bought some stamped 1U panels, the thing is, i prob need to modify the case, either make an opening, or use wood for whole backpanels.

cheers

henry

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I built an amp using the 2 x 100W Sure modules. I cobbled together a linear 27V PS using a 160VA toroid, a 50A bridge and some old Nippon Chemicon 10,000uf electros all stuffed into an Altronics 2RU case. I removed the surface mount 22uf input electros and replaced them with 10uf Wima caps. I've listened extensively to all sorts of music and these amps are hard to beat. Normally I run valve monoblocks and the Sure amp gives them a run for their money. In fact if I hadn't invested so much in the valve amps I would find it hard not to listen to the Sure amp all the time.

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The fan runs all the time but is quiet. I have unplugged the fan to see if the amp gets hot and it doesn't at my listening levels. The little amount of fan noise can be almost eliminated by putting a DVD case over each set of vent slots in the case lid. I can't hear the fan from my listening position. The vent slots aren't necessary as the case soaks up any heat.

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