UcD400HG MonoBlocks project... help please

[croger]

Hello DIY'ers. this is my first foray into DIY audio. I ordered and received from Hypex UcD400HG amps, transformers, and PS's for two mono blocks. After much research on my part I figured out the proper wiring scheme. Believe me when I say I am a newbie to this. I am a Record Producer in NYC and have always wanted to build my own equipment. I figured this was a good start.

So I have a couple of questions for those more experienced.

1) I believe the proper cabling for Power Supply to UcD amp connections is 14AWG cable. But what type of cable? there are so many various types???? where can I buy in the USA?

2) The loud speaker connections from UcDamp to speaker binding post.... What cable for that? speaker wire? what type? Or just the 14AWG cable as well?

3) lame question number 3.... Can I mount the UcD400hg to the front aluminum face plate of the chassis for the heatsink? Or directly to the metal bottom? the top sides and bottom of the chassis I ordered are metal. I found a heatsink assembly that can be used on the Ucd400 from here: http://www.diycable.com/main/product_info.php?products_id=551
Is this a better solution? there will be only one amp in each case. standard 2 rack height rack mount chassis w- aluminum face plate.

Any insight or advice to wiring this thing up would be much appreciated.

thanks for any help.

Roger

 

[gl]

Hi Roger,

In order:

1) 14AWG is ideal. It's more than big enough and still small enough so that you can work with it easily. Most manufacturers who build UCD based products appear to use 14 - 16 ga cable. The most common type is PVC jacketed and you can buy it from www.mouser.cam or www.digikey.com. I always buy North American made cable. Cable from the far east is not made as well generally. So read the labels and make sure it's made by someone reputable. Some people will tell you that PVC sounds bad. I'm not in that camp. But you can buy Teflon jacketed or other exotic cable if you choose. Try www.percyaudio.com for the exotic stuff.

2) Use the same 14AWG cable as everywhere else. Keep this connection very short. In fact keep all of your hookup wires very short.

3) Not a lame question at all. Just bolt the module to your chassis. Not much heatsinking is necessary for a 400.

You will want to read everything you can on the Hypex site regarding hook-up and grounding especially. There are also lots of good threads here on this site you can browse.

Good luck. It sounds like a fun project.

Graeme

 

[croger]

Thank alot Graeme,

these simple insights do help me alot. just to know what cable everyone uses helps me. I emailed a layout of all the amp components with the wiring to hypex support to make sure all my connections are correct. Luckily I had them right. Now I just need to wait for my 2 chassis to arrive on monday and get the wires and input and speaker connectors and i am good to go!

thanks
roger

Hi Roger,

In order:

1) 14AWG is ideal. It's more than big enough and still small enough so that you can work with it easily. Most manufacturers who build UCD based products appear to use 14 - 16 ga cable. The most common type is PVC jacketed and you can buy it from www.mouser.cam or www.digikey.com. I always buy North American made cable. Cable from the far east is not made as well generally. So read the labels and make sure it's made by someone reputable. Some people will tell you that PVC sounds bad. I'm not in that camp. But you can buy Teflon jacketed or other exotic cable if you choose. Try www.percyaudio.com for the exotic stuff.

2) Use the same 14AWG cable as everywhere else. Keep this connection very short. In fact keep all of your hookup wires very short.

3) Not a lame question at all. Just bolt the module to your chassis. Not much heatsinking is necessary for a 400.

You will want to read everything you can on the Hypex site regarding hook-up and grounding especially. There are also lots of good threads here on this site you can browse.

Good luck. It sounds like a fun project.

Graeme

 

[ma_coule]

Hi (c)Roger,
we're in the same boat - i'm building UcD400HG amp too.
May I join to your thread to exchange some infos?
Cheers,

 

[glt]

I used wires from a salvaged PC power supply and for the speaker and input connectors I used mulple strands of cat5 cable. Here are some photos of a UCD 180HG project

http://picasaweb.google.com/bugandang/Hifi?authkey=xDyo5wY0VJY

 

[bearddavid]

Hi Roger,

I'd like to offer a quick word of clarification / expansion on the excellent advice gl has already given you. Regarding heatsinking - I'd definitely advise bolting the UcD400HG heatsinks to the Aluminium [Correct English spelling ] front or rear panel of your chassis - actually any panel as long as it's Aluminium as steel is a pretty lousy conductor of heat.

I'm just about to build a UcD400HG based pair of monoblocks - I've got all the electronic bits now and I'm trying to decide what to do on the part which will be most difficult for me - the chassis!

May I ask what you guys are using for your chassis?

Cheers
Dave

 

[croger]

yeah. I heard that steel is a bad heatsink. I am still undecided if I will spend the extra $100.00 US dollars to buy speacial heatsink assembly for each amp. they look cool as well. (from www.duycable.com) I am leaning to not and just bolt them to each aluminum front plate.
I got my two chassis from www.par-metal.com

you being in Dubai I am not sure where you should buy from.
here are other places I found.
http://www.modushop.biz/ecommerce/index_l2.php
and
http://www.atiresearch-anodized.com/products.html

I orderd from par-metal because they are in New Jersey, I am in NYC. so they are literally 10 miles from NYC. easy shipping.

It seems there are quite a few people building these 400 monoblocks!

Hi Roger,

I'd like to offer a quick word of clarification / expansion on the excellent advice gl has already given you. Regarding heatsinking - I'd definitely advise bolting the UcD400HG heatsinks to the Aluminium [Correct English spelling ] front or rear panel of your chassis - actually any panel as long as it's Aluminium as steel is a pretty lousy conductor of heat.

I'm just about to build a UcD400HG based pair of monoblocks - I've got all the electronic bits now and I'm trying to decide what to do on the part which will be most difficult for me - the chassis!

May I ask what you guys are using for your chassis?

Cheers
Dave

 

[croger]

ok... now i have to bug you with questions as i build my amps...

I used wires from a salvaged PC power supply and for the speaker and input connectors I used mulple strands of cat5 cable. Here are some photos of a UCD 180HG project

http://picasaweb.google.com/bugandang/Hifi?authkey=xDyo5wY0VJY

 

[croger]

of course!

Hi (c)Roger,
we're in the same boat - i'm building UcD400HG amp too.
May I join to your thread to exchange some infos?
Cheers,

 

[ma_coule]

Can I mount the UcD400hg to the front aluminum face plate of the chassis for the heatsink? Or directly to the metal bottom?

Oh, yes ... you need answers too...
AFAIK, it's suggested to mount the module straight (with coil on the top!) on an Al part of chassis. Seems left and right side of chassis are most practical.

BTW, I prefer "skeleton" chassis, self made of 12x12 mm Al stick (not hard to me coz mechanical engineering is my profession). It's stable without cover and so very practical for amp tweaking. At the end you only close the whole construction with Al sheet cover pieces.
But... who knows which is the best for you?
Cheers,

 

[glt]

I think these modules can be mounted anywhere and in Al or steel. Just make sure you apply some thermal compound (the same stuff used to mount heatsinks to PC processors) to ensure good contact. These modules are 90+ % efficient.

 

[TheMG]

Mounting the module to the chassis should work fine for normal use.

However if you intend to drive these at their maximum output and in a tight area with limited ventilation, heatsinking may be required.

Even though it's 90% efficient, at 400W output power you're going to be dissipating roughly 45W of heat, which may not seem like much, but if it's allowed to build up can reach some high temperatures.

I'd opt for mounting it on the side of the chassis rather than the bottom. You want hot air to rise along the side of the chassis, rather than build up a pool of hot air underneath the chassis.

 

[Iyremenko]

Scary, this advice. Start with reading the manual, page 1, where it say's "cooling" in big bold letters.

http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html

 

[glt]

The heatsinking will only pull the heat from the power transistors. You need some ventilation for the rest of the circuitry of the module. If you mount the modules to the bottom then the circuit board will be in a vertical position which facilitates ventilation for the rest of the circuit. I mounted mine to the side and drilled some holes under and above the module. But I don't drive the amps that hard, just normal listening volume

 

[croger]

powersupply output voltage

so i have my monoblocks all wired up now.

TR400 transformer
ucd supply hg mono power supply
ucd400hg amp module

I do not have the power supply connected to the amp yet.
If I measure the DC voltage on the supply rails I get +/- 65.9 volts.

the ucd400hg amp is specd to max voltage input 65 volts. with over current protection kicking in at 68 volts.

I emailed hypex as well. I want DIYaudio memebers opinions as well. What issues will I have with it over the max input voltage? why is it so high off my power supply?

thanks for any input.

 

[TheMG]

That seems a little high. With a 40 volt tranny you should be getting a maximum no-load voltage of +/-56.5V once rectified.

It may be because your mains AC voltage is higher than 115V/230V which is what the transformer is spec'd at. This is not a bad thing, it just means you get a little more voltage out the transformer than 40V.

What doesn't seem right though is that you're getting 65V rectified, which doing the math would mean you have a 132V/264V AC mains, which seems too high to be true.

Hmmm... this definitely has me scratchin my head.

Rest assured though that it is still within the UCD400 safe operating specs (just barely) and that the voltage will sag a little once you turn up that volume knob!

 

[Iyremenko]

Re: powersupply output voltage

so i have my monoblocks all wired up now.

TR400 transformer
ucd supply hg mono power supply
ucd400hg amp module

I do not have the power supply connected to the amp yet.
If I measure the DC voltage on the supply rails I get +/- 65.9 volts.

the ucd400hg amp is specd to max voltage input 65 volts. with over current protection kicking in at 68 volts.

I emailed hypex as well. I want DIYaudio memebers opinions as well. What issues will I have with it over the max input voltage? why is it so high off my power supply?

thanks for any input.

Overcurrent doesn't trip at 65 volts, overvoltage might. All you're seeing is the unloaded voltage of the transformer, look up the regulation factor of 400VA toroid and try working the numbers again.

Since it is within the safe limits of the modules, connect them and you'll see the rails drop a few volts more even with the amps disabled, more still when they're idling, more still while under load.

It makes a big difference when you have a load on it. Don't forget to drain the caps you've charged up with a power resistor before connecting the modules.

Why waste their time by asking the same question to the forum as you emailed them with?

 

[croger]

Re: Re: powersupply output voltage

Why waste their time by asking the same question to the forum as you emailed them with?

Thanks for the info. I wanted the opinion of hypex and the opinion of people on this forum is why I asked at both places. their reply is below pasted from email from Frank at hypex, who has been a great help with my project. I will post some pics of my amp when finished.

______________________________________________
+/- 66V is a little on the high side, but definitely doesn’t have a negative influence on the sonic performance. Also, when the amplifier is connected and it starts to output more power, the supply voltage will lower a bit. But as log as it doesn’t go in over voltage protection there should be no problems. When it is in over voltage protection the amp simply won’t turn on. So it is absolutely safe to connect the amplifier to the supply. But I don’t think there will be any problems with this situation.

Best regards,

Frank Veldman

 

[croger]

What doesn't seem right though is that you're getting 65V rectified, which doing the math would mean you have a 132V/264V AC mains, which seems too high to be true.

Hmmm... this definitely has me scratchin my head.

Rest assured though that it is still within the UCD400 safe operating specs (just barely) and that the voltage will sag a little once you turn up that volume knob!

thanks. the building is an old buiding that was an old garment factory that is converted to a recording studio. I have all the recording studio equipment and computers, etc on ac conditioners regulated power supplies. the bench where I am assembling the UcD how ever has the power coming right off a unregulated AC main. so maybe after I hook the amps up to a regulated power receptacle the AC will be more normal.