Some attempts of explaining that can be found in this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=21079&highlight=
http://www.diyaudio.com/forums/showthread.php?s=&threadid=21079&highlight=
Re: Inverting has lower distortion
Because theoretically there may be a difference in THD's 3rd or 4th digit after the zero, which I don't think you'll hear anyway. There are much more important considerations that would make much bigger difference in the sound of the amp.
Imput impedance, type of components or the powersupply comes to mind.
/Greg
Kurt said:
Because theoretically there may be a difference in THD's 3rd or 4th digit after the zero, which I don't think you'll hear anyway. There are much more important considerations that would make much bigger difference in the sound of the amp.
Imput impedance, type of components or the powersupply comes to mind.
/Greg
I haven't had much time to check in here lately... some great info!
Thanks for all that.
I've just made my first move towards a first project (still a lot going on here.. no promises of speed!)...
Decided to build a power supply to kick this off, going to build a stand-alone power supply so that I can experiment with different things... with the LM3886 in mind.
Just ordered an Avel Lindburg 625VA transformer with 25v secondaries, and a couple single-unit bridge rectifiers and diodes to play with so far (I've got a couple dual-unit fast-diodes here too, not sure how I'm going to go with the rectification).
The experimenting is definitely part of the learning.
Thanks for all that.
I've just made my first move towards a first project (still a lot going on here.. no promises of speed!
)... Decided to build a power supply to kick this off, going to build a stand-alone power supply so that I can experiment with different things... with the LM3886 in mind.
Just ordered an Avel Lindburg 625VA transformer with 25v secondaries, and a couple single-unit bridge rectifiers and diodes to play with so far (I've got a couple dual-unit fast-diodes here too, not sure how I'm going to go with the rectification).
The experimenting is definitely part of the learning.
can you tell me
what the max VA is that I can install in the gc's without wasting amperes dollars ...... I thought I ahd read somewhere that one channel should not need more than 25 v 8 A = 200 VA... is that correct? Because of my ineptitude I do not seem to find any of that in the datasheet from the LM 3875 ........
J-P
Nuuk said:In that case, try a 160VA transformer too! Bigger is NOT always better.
what the max VA is that I can install in the gc's without wasting amperes dollars ...... I thought I ahd read somewhere that one channel should not need more than 25 v 8 A = 200 VA... is that correct? Because of my ineptitude I do not seem to find any of that in the datasheet from the LM 3875 ........
J-P
I would say there is no difinitive answer to that question. Perhaps easier to answer is what is the minimum VA you can use without affecting sound quality. To that I would answer that I have had fantastic sound with a single 120VA (for both channels) and currently find that one 80VA per channel works well too.
Of course, this could well be dependant on which speakers you connect the amp to.
in that case
i can state even lower values...
I always use (to test the connections) 2 transformersper channel (basler 20 v, 1.2 a) , they have no CT so i connect the bottom wire of one trannie to the upper wire of the other trannie so tha I get a 0 volt point for ground etc...
I don't know if the amps go up, maybe 2.4 A?????
anyway, the sound is not loud but very very nice and sweet.........
nice bass etc..etc...
J-P
the brand is Basler and I bought them surplus for $2.49 a piece, no hum, no defects nothing, just perfect and they are still available.... at B.G Micro
Bassler Trans
Price: $2.49
Part No.: PWR1013
Product Description
Bassler transformer. 115 VAC input. Secondary: 20 VAC/1.2A
i can state even lower values...
I always use (to test the connections) 2 transformersper channel (basler 20 v, 1.2 a) , they have no CT so i connect the bottom wire of one trannie to the upper wire of the other trannie so tha I get a 0 volt point for ground etc...
I don't know if the amps go up, maybe 2.4 A?????
anyway, the sound is not loud but very very nice and sweet.........
nice bass etc..etc...
J-P
the brand is Basler and I bought them surplus for $2.49 a piece, no hum, no defects nothing, just perfect and they are still available.... at B.G Micro
Bassler Trans
Price: $2.49
Part No.: PWR1013
Product Description
Bassler transformer. 115 VAC input. Secondary: 20 VAC/1.2A
I have seen several cases put forward for a smaller, rather than larger PSU. One was by Hugh Dean of AKSA fame who I have a lot of respect for.
And I wonder if this is the reason that the Gaincard is said to sound better with one PSU?
It's possible that a chip amp may be even better suited to the correct amount of VA than a discrete circuit - who knows?
Unfortunately, many people still adhere to the 'bigger is better' principle and spend money on more VA, sometimes instead of better caps/resistors etc.
And I wonder if this is the reason that the Gaincard is said to sound better with one PSU?
It's possible that a chip amp may be even better suited to the correct amount of VA than a discrete circuit - who knows?
Unfortunately, many people still adhere to the 'bigger is better' principle and spend money on more VA, sometimes instead of better caps/resistors etc.
why monolithic?
i am not sure as to why the gainclone is so popular,
- im not fully arare of its drive circuitry - tho as far as i know its based on some monolithic TDA serirs or so monolithic IC, which i believe comes all back to the basics of all output ICs - that being inverting/noninverting inputs, supply rails, output etc...
why not replace them monolithics w/ STK4050V or the likes
lets see a monolithic keep stable at a min of 200W per IC
now if they designed this multi chip amplifier circuit based on 4050V hybrid ICs i bet that this would revolutionize the existing performance of the same drive circuit
- ideas
- comments
mmm im interested as to why base a concept of operation on a small range of monolithic ICs when you can do much better with this based on more capable and robust ICs
- Baily
i am not sure as to why the gainclone is so popular,
- im not fully arare of its drive circuitry - tho as far as i know its based on some monolithic TDA serirs or so monolithic IC, which i believe comes all back to the basics of all output ICs - that being inverting/noninverting inputs, supply rails, output etc...
why not replace them monolithics w/ STK4050V or the likes
lets see a monolithic keep stable at a min of 200W per IC
now if they designed this multi chip amplifier circuit based on 4050V hybrid ICs i bet that this would revolutionize the existing performance of the same drive circuit
- ideas
- comments
mmm im interested as to why base a concept of operation on a small range of monolithic ICs when you can do much better with this based on more capable and robust ICs
- Baily
Re: why monolithic?
I guess one reason could be that not all people want to:
"Ride the Lightning...Feel the Thunder"
Me, I'm quite fine with LM3875 at 20W/ch. in a small footprint.
/Greg
SVI2004A said:i am not sure as to why the gainclone is so popular,
- im not fully arare of its drive circuitry - tho as far as i know its based on some monolithic TDA serirs or so monolithic IC, which i believe comes all back to the basics of all output ICs - that being inverting/noninverting inputs, supply rails, output etc...
why not replace them monolithics w/ STK4050V or the likes
lets see a monolithic keep stable at a min of 200W per IC
now if they designed this multi chip amplifier circuit based on 4050V hybrid ICs i bet that this would revolutionize the existing performance of the same drive circuit
- ideas
- comments
mmm im interested as to why base a concept of operation on a small range of monolithic ICs when you can do much better with this based on more capable and robust ICs
- Baily
I guess one reason could be that not all people want to:
"Ride the Lightning...Feel the Thunder"
Me, I'm quite fine with LM3875 at 20W/ch. in a small footprint.
/Greg
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.