Chassis Layout
Hi,
I am pulling together the last few parts for my UCD180-AD amp. The final choice is the chassis. The rest of my DIY system uses some nice aluminum boxes from Par-Metal so I would like to match them. They are small in size being 12 x 8 x 3 inches. I have figured out the layout and it will work but am a little concerned about radiated fields within the chassis from the AC, trannie, and class D modules being close together.
My question: Is it worthwhile using a couple of aluminum dividers to separate out the different sections or would this be a waste/unnecessary?
I am enjoying the thread about copper foil. I was thinking about shielding some PP input caps. What would be a good source/choice for foil
Thanks,
Paul
Hi,
I am pulling together the last few parts for my UCD180-AD amp. The final choice is the chassis. The rest of my DIY system uses some nice aluminum boxes from Par-Metal so I would like to match them. They are small in size being 12 x 8 x 3 inches. I have figured out the layout and it will work but am a little concerned about radiated fields within the chassis from the AC, trannie, and class D modules being close together.
My question: Is it worthwhile using a couple of aluminum dividers to separate out the different sections or would this be a waste/unnecessary?
I am enjoying the thread about copper foil. I was thinking about shielding some PP input caps. What would be a good source/choice for foil
Thanks,
Paul
Hi, dividers really aren't a necessity with these modules, consider their use going the extra mile.
As per your question on the filter cap, mine is soldered to the ground lug underneath the PCB, and to the orignal mounting via, as close to the board as possible, minimal loop area is key.
It's very strong, but I don't intend on standing on it either.
As per your question on the filter cap, mine is soldered to the ground lug underneath the PCB, and to the orignal mounting via, as close to the board as possible, minimal loop area is key.
It's very strong, but I don't intend on standing on it either.
25V secondaries
I happen to have two transformer 225VA transformer with 25V secondaries - can I use this to put together a UCD180? 25V secondaries should give me 35V rails - around 34V after the diode drop.. This is above the minimum of 30Vs but pretty far off from the typical ratings of 45V. What is the implications of using 35V rails? versus 45V? will I get a lower power output? any impact on sound quality?
Thanks!
I happen to have two transformer 225VA transformer with 25V secondaries - can I use this to put together a UCD180? 25V secondaries should give me 35V rails - around 34V after the diode drop.. This is above the minimum of 30Vs but pretty far off from the typical ratings of 45V. What is the implications of using 35V rails? versus 45V? will I get a lower power output? any impact on sound quality?
Thanks!
A question of power
In a word, yes. You will take a big hit in power out with probably less than 65watts available with this transformer. I would think this would have to hurt the sonics a lot as well.
This transformer would be just right for the 41Hz amp one however. Using it would give you stereo and be a lot cheaper.
Roger
In a word, yes. You will take a big hit in power out with probably less than 65watts available with this transformer. I would think this would have to hurt the sonics a lot as well.
This transformer would be just right for the 41Hz amp one however. Using it would give you stereo and be a lot cheaper.
Roger
Out of curiosity, what formula would I use to calculate output power for a given rail voltage and impedance for these amps?
Thanks!
Thanks!
Re: A question of power
[Thanks! so, I will have to get transformers with 30V secondaries. If I am using 2 UCD180s in 1 chassis, do I need a softstart module? Is the current draw that large? I feel that I can get away without it, but would appreciate input from those who have done it (without the softstart module)
QUOTE]Originally posted by sx881663
In a word, yes. You will take a big hit in power out with probably less than 65watts available with this transformer. I would think this would have to hurt the sonics a lot as well.
This transformer would be just right for the 41Hz amp one however. Using it would give you stereo and be a lot cheaper.
Roger [/QUOTE]
[Thanks! so, I will have to get transformers with 30V secondaries. If I am using 2 UCD180s in 1 chassis, do I need a softstart module? Is the current draw that large? I feel that I can get away without it, but would appreciate input from those who have done it (without the softstart module)
QUOTE]Originally posted by sx881663
In a word, yes. You will take a big hit in power out with probably less than 65watts available with this transformer. I would think this would have to hurt the sonics a lot as well.
This transformer would be just right for the 41Hz amp one however. Using it would give you stereo and be a lot cheaper.
Roger [/QUOTE]
Reversing polarity
Hi!
I've run in to a strange phenomena lately, where one of my JBL 2441 midranges driver is getting a reversed polarity signal off and on.
I'm running three way speakers, actively driven by DIY amps with UcD180 modules for the high section
and a couple of UcD400 modules for the low section.
I have swapped drivers, I have replaced the pre amp and I have replaced the Behringer Ultradrive, but still the right hand side midrange driver, is getting a reversed signal from time to time.
Is it at all possible, that the Hypex module, internally could cause such a polarity switch on the balanced signal?
Grateful for any help
BR
Roland
Hi!
I've run in to a strange phenomena lately, where one of my JBL 2441 midranges driver is getting a reversed polarity signal off and on.
I'm running three way speakers, actively driven by DIY amps with UcD180 modules for the high section
and a couple of UcD400 modules for the low section.
I have swapped drivers, I have replaced the pre amp and I have replaced the Behringer Ultradrive, but still the right hand side midrange driver, is getting a reversed signal from time to time.
Is it at all possible, that the Hypex module, internally could cause such a polarity switch on the balanced signal?
Grateful for any help
BR
Roland
Q & A
Answer (1)
A rule of thumb power calculation formula I use is 1.414 X transformer voltage to give peak then -3 to -5 volts to cover losses. In this case I think closer to -3 would be appropriate.
Take this voltage times .707 and divide it by 8 for the RMS current then multiply it by the voltage for the RMS power. This should give you a little margin to work with for varying line voltages. For instance the amp I just did calculated out to 200W and actually does 203 at just reaching clipping.
Answer (2)
The transformer would hurt sonics by being less powerful. This means the source impedance the amp sees is higher due to copper losses and core losses. This will soften the bass drive and reduce the sound staging. Even in low demand devices like preamps a heaver power supply will sound better even if the only component upgraded is the transformer.
Roger
Answer (1)
A rule of thumb power calculation formula I use is 1.414 X transformer voltage to give peak then -3 to -5 volts to cover losses. In this case I think closer to -3 would be appropriate.
Take this voltage times .707 and divide it by 8 for the RMS current then multiply it by the voltage for the RMS power. This should give you a little margin to work with for varying line voltages. For instance the amp I just did calculated out to 200W and actually does 203 at just reaching clipping.
Answer (2)
The transformer would hurt sonics by being less powerful. This means the source impedance the amp sees is higher due to copper losses and core losses. This will soften the bass drive and reduce the sound staging. Even in low demand devices like preamps a heaver power supply will sound better even if the only component upgraded is the transformer.
Roger
Re: Q & A
So a passive preamp does not have this problems?
BTW, tested 2 stereo UCD400AD amps with a 300VA and 500VA toroid, did a direct A-B switching comparison and cannot tell the difference.
sx881663 said:
So a passive preamp does not have this problems?
BTW, tested 2 stereo UCD400AD amps with a 300VA and 500VA toroid, did a direct A-B switching comparison and cannot tell the difference.
Currently I have 2 UcD 180 monoblocks using 160VA 22-0-22 xfmr each. I'm thinking about new power xfmrs with 30-0-30 secondaries, I'm trying to decide between 250VA or 330VA. Would the 330VA be considered overkill for this setup considering most of my current speakers are nominal 8 ohms, although who knows what the future may hold...😀
330 or 250 is hardly any difference. Doubt if you will ever notice.
But going from 2 to 1 transfo's will have some influences(crosstalk).
But going from 2 to 1 transfo's will have some influences(crosstalk).
Thanks for the reply!
Sorry if I wasn't clear, these will still be monoblocks, so that means one xfmr per UcD 180.
From your answer I assume you don't feel that a 330VA xfmr would be overkill for one UcD 180?
Sorry if I wasn't clear, these will still be monoblocks, so that means one xfmr per UcD 180.
From your answer I assume you don't feel that a 330VA xfmr would be overkill for one UcD 180?
I don't think it would be overkill... might not be that much of a difference but it sure won't hurt.
