Sweet!!
Sounds like an Alpha Nirvana has been born 😀
Looking forward to seeing some pics when you get around to it JT.
Sounds like an Alpha Nirvana has been born 😀
Looking forward to seeing some pics when you get around to it JT.
Thanks V, I am not close to that yet, but when I get both done and cleaned up, I shall do so. If this sounds as good as I hope these monos will get moved to the music room for their turn in the rotation.
Ground Planes...
Okay, I have your drawing X of all the groundings, but have some questions about the differences in potential I'm seeing.
On the AN board itself, I'm seeing about 49R between the neg speaker and Zero Out.
On the SLB, I am seeing about 7R7 between the L&R grounds and the PE out. I assume that one is caused by the 8207 protection.
You know I don't know much, but I wonder about all the potential ground differences, or at least what I see as ground potential differences.
I see by all the ground wires you have running all over in your build that maybe this is to take care of this?
Thanks
J
Okay, I have your drawing X of all the groundings, but have some questions about the differences in potential I'm seeing.
On the AN board itself, I'm seeing about 49R between the neg speaker and Zero Out.
On the SLB, I am seeing about 7R7 between the L&R grounds and the PE out. I assume that one is caused by the 8207 protection.
You know I don't know much, but I wonder about all the potential ground differences, or at least what I see as ground potential differences.
I see by all the ground wires you have running all over in your build that maybe this is to take care of this?
Thanks
J
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I guess when it comes to it there is only the one thing... I have grounded as you did, but that leaves us with a zero out and speaker at the same potential, but PE to Zero out at 7R7 is this an issue?
JT
JT
A little OT, my experience with Dell (short version). About a year ago I ordered 10 of the FD841 coolers from Dell. They kept delaying shipment due to logistics with coolers in stock. They finally sent me an email cancelling the order. Since this has happened, the prices for these coolers on ebay & other sites has increased, especially shipped to Canada. I have looked at other modern coolers with TPD of 120W or >, with the direct contact heat pipes (no gaps between pipes on contact surface), and have found some decent prices complete with fans. I have also checked on the pad dimensions of the 4 pipe coolers and they seem suitable enough for 1 mosfet and possibly 1 extra device. Anyways, just my experience and the pathways we have to travel in DIY.
MM
MM
Not sure about your notation, but 49R means 49ohms. You are talking about voltage between output and ground and this should be below 50mV or so. So do you mean 49mV? Typically I see 5mV to 25mV. But 50mV is still acceptable. If you want less DC offset you can try matching the Hfe of the input KSA992’s. Have you done that?
50mV DC offset is about 20mW of dissipation on the voice coil of an 8ohm driver. Not much to worry about.
You said 49 ohms above same as 49R. Why are you measuring or care about ohms between the output and ground? You mean millivolts?
I have not read the whole thread so there might be vital info related to my question that I have missed.
Q: Would it be possible to adapt the SLB to work with Purifi 1ET400a class D as an alternative to Hypex SMPS ?
Q: Would it be possible to adapt the SLB to work with Purifi 1ET400a class D as an alternative to Hypex SMPS ?
It depends on how much power you want to run the IET400 amp at. It’s a 400w amp and the specs say it’s capable of 25A at +/-65v rails. That’s a huge amount for any PSU.
SLB is designed for Class A amps requiring up to 5A continuous current with only 1mV rms ripple.
Most Class D amps don’t require such clean power supplies. I think you can get by with just a standard or active bridge and a CRC and no cap multiplier. You could just use the active bridge and CRC (sized appropriately for a max of 25A) and skip the cap Mx.
If you don’t need 400w and 150w is enough for you, you might consider the TPA3255 reference amp GB. It’s the only implementation with a second harmonic dominant distortion profile. Still very low THD at 0.00247% and could be used with a SLB single rail version at 48v.
TPA3255 Reference Design Class D Amp GB
SLB is designed for Class A amps requiring up to 5A continuous current with only 1mV rms ripple.
Most Class D amps don’t require such clean power supplies. I think you can get by with just a standard or active bridge and a CRC and no cap multiplier. You could just use the active bridge and CRC (sized appropriately for a max of 25A) and skip the cap Mx.
If you don’t need 400w and 150w is enough for you, you might consider the TPA3255 reference amp GB. It’s the only implementation with a second harmonic dominant distortion profile. Still very low THD at 0.00247% and could be used with a SLB single rail version at 48v.
TPA3255 Reference Design Class D Amp GB
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I have no idea how this post arrived here!
This post was in the ABBB thread. It is no longer there and has shown up in this thread. I have no idea how. Sorry for this.
MM
This post was in the ABBB thread. It is no longer there and has shown up in this thread. I have no idea how. Sorry for this.
MM
cpu heatsinks
Hi Vunce,
Wish I could find Dell coolers at a reasonable price. Had to settle on the HP heatsinks (like jwjarch purchased). The thermal copper pad is 38mm x 31 mm, so it should be enough room for a mosfet & a BJT transistors. That is, if I am reading the data sheets correctly.😀. Good for around 130W dissapation. Happy building!!
MM
Hi Vunce,
Wish I could find Dell coolers at a reasonable price. Had to settle on the HP heatsinks (like jwjarch purchased). The thermal copper pad is 38mm x 31 mm, so it should be enough room for a mosfet & a BJT transistors. That is, if I am reading the data sheets correctly.😀. Good for around 130W dissapation. Happy building!!
MM
Kokanee,
These HP’s also have a very large copper area. Search for DL580
“HP CPU cooler LGA1567 DL580 G7 DL980 G7 591207-001 570259-001”
LOT OF 2 HP LGA1567 CPU Heatsink for DL580 G7 DL980 G7 591207-001 570259-001 39517463831 | eBay
These HP’s also have a very large copper area. Search for DL580
“HP CPU cooler LGA1567 DL580 G7 DL980 G7 591207-001 570259-001”
LOT OF 2 HP LGA1567 CPU Heatsink for DL580 G7 DL980 G7 591207-001 570259-001 39517463831 | eBay
Hi X,
Those are the models that I purchased. I asked the seller the dimensions of the thermal copper plate. The seller replied with 1.5" x 1.25". I will see when they arrive. Pretty confident they will work. The Dells are getting hard to find in N.America at a good price. Shipping from China is crazy.
MM
Those are the models that I purchased. I asked the seller the dimensions of the thermal copper plate. The seller replied with 1.5" x 1.25". I will see when they arrive. Pretty confident they will work. The Dells are getting hard to find in N.America at a good price. Shipping from China is crazy.
MM
Ok, good. I think they will works fine. They are nice in that they don’t have a long heat pipe poking out like the Dell’s. With a 120mm Noctua fan, you will be fine even up to 160w would be my guess.
Hi David,
Just get the SLB single rail version. Build it per the BOM. I think ACA’s are currently running at 24v single rail and circa 1.25 to 1.5A bias current? You could power two channels off of one SLB. Or go dual monoblocks for best soundstage and low noise.
I would get at least a 250VA 22v trafo for mono and 400VA 22v trafo for stereo from one SLB.
Personally I would go dual mono. The 22v trafo makes 31v no load. It will sag about 3v to 4v under load. That’s 28v about. The cap multiplier will drop another 3v for 25vdc. 25v gives you a little more headroom. Won’t be a big deal to cool that extra volt.
Hope that helps.
Just get the SLB single rail version. Build it per the BOM. I think ACA’s are currently running at 24v single rail and circa 1.25 to 1.5A bias current? You could power two channels off of one SLB. Or go dual monoblocks for best soundstage and low noise.
I would get at least a 250VA 22v trafo for mono and 400VA 22v trafo for stereo from one SLB.
Personally I would go dual mono. The 22v trafo makes 31v no load. It will sag about 3v to 4v under load. That’s 28v about. The cap multiplier will drop another 3v for 25vdc. 25v gives you a little more headroom. Won’t be a big deal to cool that extra volt.
Hope that helps.
cpu heatsinks
Not sure if this will work. I am trying to attach a screen shot of some cpu heatsinks.😕
Not sure if this will work. I am trying to attach a screen shot of some cpu heatsinks.😕