I built a 6-24 crossover in a Hammond steel chassis. For the power transformer, I liberated the PT from a wall wart supplied with the B-1 preamp kit. I put the crossover in my main system without the bottom plate, which in my setup is actually the top plate, and it worked great. No noise, excellent "transparency", and I was a happy boy. Then I tried to put the cover on, and as soon as the plate was over the transformer and rectifiers, it started to vibrate like mad. Without the cover, I can feel no vibration when touching the transformer or the chassis that it is mounted in. When the plate is over the tranny, both the PT and the cover vibrate. It is loud! With the Audiotools 1/3 octave RTA on my iphone, and a Dayton Audio microphone, I measure spikes at 125 and 250 hz. What is going on? Any suggestions on how to fix this?
Probably not related but I know having the bolt through a toroidal transformer touching the top and bottom of a chassis causes a shorted turn and causes havoc.
I posted 3 pics of my completed build on page 63, post #623 of the DIY biamp 6-24 crossover thread. I will take more later.
that would be DIY biamp 6-24 crossover
I can't see anything wrong , what could result in magnetic short ( as usual when making a mistake with toroid fixing arrangement)
except - xformer you used looks sorta cheapo
I know it is a mess, but try to move just mains xformer temporary out of case, keeping exactly same wiring scheme ( just prolonging wires)
if you don't have same problem that way, xformer is culprit - emanating so nasty magnetic pulses that case is behaving as short winding
I can't see anything wrong , what could result in magnetic short ( as usual when making a mistake with toroid fixing arrangement)
except - xformer you used looks sorta cheapo
I know it is a mess, but try to move just mains xformer temporary out of case, keeping exactly same wiring scheme ( just prolonging wires)
if you don't have same problem that way, xformer is culprit - emanating so nasty magnetic pulses that case is behaving as short winding
Can't see very clear. Seems you have IEC, fuse, and power switch there, I do suspect their wiring and maybe include the PSU part. Also, I don't use IEC earth in most gears...where your IEC earth connected to?
In theory it's good safety practice...
In reality, check factory machines, how many 2 prongs...don't just simply say yes no copying others.
In reality, check factory machines, how many 2 prongs...don't just simply say yes no copying others.
there is so called dual or double isolation standard, and that sort of gadgets you'll find with no IEC
if you are familiar with that standard, make it without IEC
if you are familiar with that standard, make it without IEC
The safety ground is connected directly to the chassis. The power supply ground is connected to the chassis ground through a CL-11 thermistor.
Ah, well. I should know by now to be suspicious whenever a project works the first time that I turn it on. 😉 Now to find a replacement power transformer that will fit in the same space. Is there a minimum VA for this transformer? Meanwhile, I want to thank Nelson for a great "sounding" piece of gear. The 6-24 replaced a Marchand XM-9 crossover with LM4562 op amps in my system. I built it with the parts listed in the article; no "magic" capacitors. I try to be aware of confirmation bias when listening to new stuff. But the 6-24 seems more "transparent" (I'm not good with audiophile descriptions) and have better bass definition than the Marchand. Thanks, Nelson!
you can measure current draw as voltage across first series resistor in PSU filter
divide V with R, that's I
multiply that current with DC you're getting after diode bridge, multiply that with at least 2, that is VA of xformer you need
did you tried moving present xformer out, and what happened , if you did it?
divide V with R, that's I
multiply that current with DC you're getting after diode bridge, multiply that with at least 2, that is VA of xformer you need
did you tried moving present xformer out, and what happened , if you did it?
I have not moved the transformer from the chassis. I am enjoying the crossover too much to take it out of the rack yet. It works fine as long as I don't try to put the cover on, so there is no rush to change anything.
right attitude!
who need cover, at all!
make clear plastic one, problem solved and you can still peek inside
who need cover, at all!
make clear plastic one, problem solved and you can still peek inside