I'm having a problem...

[ptwining]

I have completed my UCD 180 setup.

2 UCD 180 modules
1 Avel Lindberg Toroid (2x30v secondaries)
1 Hypex ST power supply

When I power my system above about 80% I get periodic cutouts - one channel shuts down (light goes off) for quick bursts at the high power transients. Turn it down a tick - all is okay.

I am running (because I am testing the speaker design) 1xKilpsch KG2 and 1 x floor stander of my design (MTMWW) running 2 x Dayton 10" reference series woofers and 2 x CSS WR125 (running full range) + 1 x Dayton silk dome tweeter on a Dayton 3-way XO @ 700/5600 in a divided cabinet (1.5cf / 2.5/cf - both sized as per Winisd)

The fullrangers are not crossed over but the woofers and the tweeter are. The Dayton XO is set to 8 ohm for the woofers (optional)

My speaker (whichever channel I run it on) gets dropped out at high power levels (which by the way are no where near what I expected for a 180 w/ch amp).

What am I doing wrong?

What's up?

[edit]
The amps are clean and wonderful except for this cutout.

Regards,
Tom

[classd4sure]

Hi,

Are your modules DC coupled?

[phase_accurate]

What is your speaker's impedance at low frequencies ? Maybe it is the overcurrent protection that you trigger.

Regards

Charles

[ptwining]

Hi guys,

thanks for the replies...

What is your speaker's impedance at low frequencies ? Maybe it is the overcurrent protection that you trigger.

I don't know, I haven't the equipment to measure them yet.

Are your modules DC coupled?

You'll have to help me out here Chris - I don't yet understand. I built them exactly as per Hypex's very simple instructions and they seem to work well (ish).

What does DC coupled mean and what do I need to know about it?

(I am on the net now, reading up but I'd sure appreciate your input!)

Regards,
Tom

[classd4sure]

Normally the modules come AC coupled. It has a cap in the signal path to block DC voltage. The main tweak is to remove it of you can.

So the input signal has a direct DC connection and doens't have to pass through a capacitor. If if you have a high level of DC on your input, you can't DC couple it, or it will amplify that DC voltage, perhaps to too great a level. Also it can make the system prone to rail pumping, which would be worse at higher output levels. I thought you may have DC coupled your modules given your last module's failure ..

[ptwining]

I haven't altered the new set of modules at all - I wanted the simplest baseline possible after my first disaster - everything is exactly as Hypex directed.

Do you have any other ideas about what might be causing my problems?

It is looking to me like it's my loudspeaker - which isn't anything special and seems to work nicely up about 80%.

Could there be any issues regarding the physical proximity of the modules to the toroid or the power supply? They are packed in pretty tight but not in contact with each other.

Wiring error?

Am I missing something?

Regards,
Tom

[classd4sure]

It could be something with the wiring, if you're unsure draw a schematic of what you've done so we can take a look at it.

As Charles suggested it could be too low an impedance dip with your speakers, which would trip the over current protection.

Why not just test it with a regular 3way or something and see?

I strongly it's any kind of a promixaty issue unless you've got a physical short but you'd have seen the smoke already.

[ptwining]

I crawled over the wiring and it's all so straight forward that it isn't funny. I think the amps are fine. In a real sense it's hard to screw up a layout that simple (even tho I did it once already!)

I think my speaks are summing down to 2 ohms or so.

I guessing that two 8 ohm woofers and two 8 ohm mids in parallel eventually puts me at 2 ohms (as a virtual pair of 4 ohm drivers in parallel) and I don't even know what the additional 8 on the tweeter is doing to that mess.

Am I nuts? What do you think?

BTW : Thanks for helping me out

Best regards,
Tom

[classd4sure]

I think you're right. That's why I was sayin give it a try with just 3 ways

The amount of "loudness" is largely dictated by the speakers efficiency as well. So if it's not enough slam for ya, get more efficient speakers.

[ptwining]

That's what I get for gettin' greedy huh!

Gotcha - I am off the screw these cabs apart and prune them back a bit.

Thanks again - having more experienced folks around who are willing to help is invaluable!

Let's see what I can bust next -

Best regards,
Tom