Hi all! Picked up this official IRAUD7S board from a member and I am preparing to jump down the rabbit hole...
I am sure I will need some hand holding along the way as I am a die-hard tube guy and don't have much experience with Solid-state.
I have another thread in the power-supply section regarding the use of an EI trans. from a Marantz SR2700 receiver.
I have 4 6800uf 100v caps, various film caps for bypassing, some 35amp 600v bridge rectifiers and a nice enclosure.
First question; in the app note it reccomends setting the oscillating frequency EITHER by closely matching the channels to the same frequency OR ensuring they are 25khz or so different. This is adjusted by some 2k pots on the board.
Any reccomendations how to accomplish this without a scope? ( Had to sell mine before moving and dont have a new one yet...)
I am sure I will need some hand holding along the way as I am a die-hard tube guy and don't have much experience with Solid-state.
I have another thread in the power-supply section regarding the use of an EI trans. from a Marantz SR2700 receiver.
I have 4 6800uf 100v caps, various film caps for bypassing, some 35amp 600v bridge rectifiers and a nice enclosure.
First question; in the app note it reccomends setting the oscillating frequency EITHER by closely matching the channels to the same frequency OR ensuring they are 25khz or so different. This is adjusted by some 2k pots on the board.
Any reccomendations how to accomplish this without a scope? ( Had to sell mine before moving and dont have a new one yet...)
Attachments
Measuring carrier without a scope
If you have a DMM with a frequency setting , measure before the output filter when the amp is idling . ( My cheap DMM has a dual display and gives a pretty accurate reading when I measure in AC voltage setting and displays the carrier frequency on the secondary display ) .
Cheers ,
Rens
Ps . Nice speakers , Coax ? what brand ?
If you have a DMM with a frequency setting , measure before the output filter when the amp is idling . ( My cheap DMM has a dual display and gives a pretty accurate reading when I measure in AC voltage setting and displays the carrier frequency on the secondary display ) .
Cheers ,
Rens
Ps . Nice speakers , Coax ? what brand ?
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Thanks for the reply. I unfortunately do not have that function on my meter (cheap Tenma).
The speakers are Fostex studio monitors that I built new enclosures for out of BB. They are an 8" with dual spiders and a concentric planar tweeter. I love them! They are really a hidden gem that go for around $100 a pair used.
Both of the adjustment pots on the board were set to the same position when I received it. I am wondering if I can "wing-it" and just turn one a quarter turn?
I do not know the range of adjustment and it is not stated in the app note; it states only that for a lower given carrier frequency the audio bandwith might suffer...
The speakers are Fostex studio monitors that I built new enclosures for out of BB. They are an 8" with dual spiders and a concentric planar tweeter. I love them! They are really a hidden gem that go for around $100 a pair used.
Both of the adjustment pots on the board were set to the same position when I received it. I am wondering if I can "wing-it" and just turn one a quarter turn?
I do not know the range of adjustment and it is not stated in the app note; it states only that for a lower given carrier frequency the audio bandwith might suffer...
Look at post #36 of this thread. If you adjusted the pots as indicated, the frequency comes out to about 400Khz. The Sure amp is a clone (almost) of your board, so you can use these instructions.
http://www.diyaudio.com/forums/class-d/220281-sure-electronics-irs2092-250wpc-amp-build-4.html
http://www.diyaudio.com/forums/class-d/220281-sure-electronics-irs2092-250wpc-amp-build-4.html
Thanks! I will give it a try.
Had the board up and running for a while tonight. I get 58v from the Marantz transformer and the board sounds quite powerful.
There is a slight hiss when the inputs are shorted but perhaps this is normal. I dont get such a hiss from my tube amps and I have not had any sand based life forms hooked up for a while...
It seems promising though.
Had the board up and running for a while tonight. I get 58v from the Marantz transformer and the board sounds quite powerful.
There is a slight hiss when the inputs are shorted but perhaps this is normal. I dont get such a hiss from my tube amps and I have not had any sand based life forms hooked up for a while...
It seems promising though.
You will find it sounds very good.
I designed my own 2092 based stereo amplifier and was very pleased with it.
I did my own pcb and the first one was a disaster with the 2092 resetting on medium volumes. The circuit is fussy about pcb layout, ground planes and decoupling.
Its a minefield for a beginner.
I designed my own 2092 based stereo amplifier and was very pleased with it.
I did my own pcb and the first one was a disaster with the 2092 resetting on medium volumes. The circuit is fussy about pcb layout, ground planes and decoupling.
Its a minefield for a beginner.
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Thanks Nigel. Yeah, I went with the IR board because I am much more competent with tubes as opposed to SS. Tubes are much more forgiving
The effeciency of class-d is the attraction for me. I plan on bi-amping with a MiniDSP and the IRAUD7s was a no brainer for the woofer section.
Plus I already had the power trafo. which was a deciding factor.
Here is a question, the two 22uf input caps are outside of the feedback loop correct? Would there be a problem to replace them with some 10uf?
I have a pair of SilmicII that are 10uf @ 50v and the ones in there now are generic chinese JUNK.
They are working into the 3k in series with the 120k feedback resistor?
This is the hand-holding part for a tube guy
The effeciency of class-d is the attraction for me. I plan on bi-amping with a MiniDSP and the IRAUD7s was a no brainer for the woofer section.
Plus I already had the power trafo. which was a deciding factor.
Here is a question, the two 22uf input caps are outside of the feedback loop correct? Would there be a problem to replace them with some 10uf?
I have a pair of SilmicII that are 10uf @ 50v and the ones in there now are generic chinese JUNK.
They are working into the 3k in series with the 120k feedback resistor?
This is the hand-holding part for a tube guy
I am just finishing up my order from Digi-key for some odds and ends and am stuck at a power entry module / mains filter.
I am on the end of my power line (literally the LAST house) in a valley between two mountains. My power quality SUCKS. I get surges, dips, my lights flicker all the time, we replace lightbulbs way too often, ect.
Also, here in my part of austria they provide internet through the powerlines as well.
So, I am thinking a filter integrated into a power entry module would be a really good idea. Anyone have any suggestions where to start?
I have been sifting through the hundreds available and am a bit lost.
What would be the proper amperage rating for this amp?
I am on the end of my power line (literally the LAST house) in a valley between two mountains. My power quality SUCKS. I get surges, dips, my lights flicker all the time, we replace lightbulbs way too often, ect.
Also, here in my part of austria they provide internet through the powerlines as well.
So, I am thinking a filter integrated into a power entry module would be a really good idea. Anyone have any suggestions where to start?
I have been sifting through the hundreds available and am a bit lost.
What would be the proper amperage rating for this amp?
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