It surely looks cool and will give more reserve for deep bass transients.
SLB can be used for almost any Class A amp up to 5A bias current and voltage up to safety limit of the CRC caps. No need for a cap bank unless you think you need extra reserve for bass authority.
Absolutely, SLB would work very well with XA252. There is no need to alter the onboard CRC components, build as per schematic. Adding straight capacitance at the output of the SLB is a different story. After several builds utilizing dual mono SLB psu’s, my most recent Class A (Scryer) has added cap banks at the output, 22,000uf per rail.
Scryer is one of the best amps in my stable, does the added capacitance help? Who knows, I guess I could disconnect the cap banks and compare, but I’ve been reluctant to go back in because of the grin on my face after power up. 😉
I did the same, 22mF at the outputs, with my monoblock SissySIT.
They may be rated for "only" 30WPC, but you wouldn't guess that at all with their authority in the low end. L
They may be rated for "only" 30WPC, but you wouldn't guess that at all with their authority in the low end. L
I'm using SLB (400VA, +/-27VDC output without load) with M2x amplifier.
The SLB has a heatsink (150x69x36mm not anodized / naked silver).
The heatsink becomes so .. so hot.
I could not touch it even for 1 sec.
It is about 52C max with my cheap infrared thermometer.
I don't even know that the thermometer reads correctly.
Do I need a more bigger heatsink?
The SLB has a heatsink (150x69x36mm not anodized / naked silver).
The heatsink becomes so .. so hot.
I could not touch it even for 1 sec.
It is about 52C max with my cheap infrared thermometer.
I don't even know that the thermometer reads correctly.
Do I need a more bigger heatsink?
Without anodization measured temp is a bit colder than actual. Usually 55C means you can touch for 2 seconds. Enough time to react and pull hand away before burns. Probably about 60C. Add piece of masking tape or Kapton tape to heatsink to get closer to true temp since emissivity of tape is closer to 1.0.
60C heatsink is not a problem for transistors but probably means it is too small. Get a bigger heatsink if it bothers you. Also for safety so you don’t get burned.
60C heatsink is not a problem for transistors but probably means it is too small. Get a bigger heatsink if it bothers you. Also for safety so you don’t get burned.
Thank you!
I've attached masking tape on the heatsink and measure the highest temperature.
It was about 56C.
It seems there is not any problem now but it will be hotter in summer.
It's better to re-casing with additional heatsink.
I've attached masking tape on the heatsink and measure the highest temperature.
It was about 56C.
It seems there is not any problem now but it will be hotter in summer.
It's better to re-casing with additional heatsink.
Hi X and other builders,
I am thinking of using a single dual rail SLB for the Alpha Nirvana build along with a suitable single transformer. Want to get away from dual mono for awhile. Can I use 10mfd caps (rather than 15mfd) for the SLB? I have a bunch I would like to use up.
Also I am thinking of using my other dual rail SLB for the psu on the F3 clone build. I do believe that one SLB can handle the bias current of 1.7 amps for each channel. Please correct me if I am wrong.
Thanks for the help
I am thinking of using a single dual rail SLB for the Alpha Nirvana build along with a suitable single transformer. Want to get away from dual mono for awhile. Can I use 10mfd caps (rather than 15mfd) for the SLB? I have a bunch I would like to use up.
Also I am thinking of using my other dual rail SLB for the psu on the F3 clone build. I do believe that one SLB can handle the bias current of 1.7 amps for each channel. Please correct me if I am wrong.
Thanks for the help
Myles,
From post #1584 above:
The 10mF caps should be fine. If you measure the ripple to be a little high, it’s an easy fix, but I bet you’ll be fine because I’ve personally built one up like that instead of using 15mF caps. My ripple voltage was definitely under 10mV. Worst come to worst, you can replace the 10mF caps with 15mF if need be or add a cap bank downstream. The Alpha Nirvana standard build is biased at 1.7A/ch. It uses a dual rail supply (~+/- 26 to 28V). So the total draw is about ~3.5A. Review the 1st post of this thread where X has posted a scope result showing <5mV of ripple from a circuit drawing > 4A. That’s definitive data.
Now for the F3.
The F3 uses a single rail supply at +46V, at least from the schematics I’ve seen on diyaudio. Do you have a single rail SLB? Or do you have two single rail SLB’s, one for each channel? Or are you building a different F3 that uses a dual rail supply? Can you post a schematic of what you are planning on building?
Best,
Anand.
From post #1584 above:
The 10mF caps should be fine. If you measure the ripple to be a little high, it’s an easy fix, but I bet you’ll be fine because I’ve personally built one up like that instead of using 15mF caps. My ripple voltage was definitely under 10mV. Worst come to worst, you can replace the 10mF caps with 15mF if need be or add a cap bank downstream. The Alpha Nirvana standard build is biased at 1.7A/ch. It uses a dual rail supply (~+/- 26 to 28V). So the total draw is about ~3.5A. Review the 1st post of this thread where X has posted a scope result showing <5mV of ripple from a circuit drawing > 4A. That’s definitive data.
Now for the F3.
The F3 uses a single rail supply at +46V, at least from the schematics I’ve seen on diyaudio. Do you have a single rail SLB? Or do you have two single rail SLB’s, one for each channel? Or are you building a different F3 that uses a dual rail supply? Can you post a schematic of what you are planning on building?
Best,
Anand.
Or perhaps Myles, you have another dual rail SLB, (but you won’t be populating the negative voltage rail) and power both channels of the F3 from that SLB’s positive voltage rail.
X has posted the tested results of a single rail SLB on the 1st post of this thread. He has tested it up to 4A and the results showed <10mV of ripple at the current.
Best,
Anand.
X has posted the tested results of a single rail SLB on the 1st post of this thread. He has tested it up to 4A and the results showed <10mV of ripple at the current.
Best,
Anand.
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Hi Anand,
Being a newbie, and getting ahead of myself with a lot of projects on the go, I just assumed that I could use the + part of each side of the SLB for each channel of the F3. I have pcb's for is the F3 clone project from member csample. I only purchased the 2 amp boards and the cap coupling board from the GB, because I have Project 16 psu's, CRCRC psu's, LT4320 psu's, and the SLB's. I figured one would work for powering the F3 clone.
Thinking I will cool my jets as far as the F3 goes and finish my work on the preamps and the Nirvana. When I get around to building the F3, I will immerse myself in the thread and go from there.
From your last post 1594, it sounds like the F3 can be powered by 1 SLB, correct or not correct?
Thanks,
MM
Being a newbie, and getting ahead of myself with a lot of projects on the go, I just assumed that I could use the + part of each side of the SLB for each channel of the F3. I have pcb's for is the F3 clone project from member csample. I only purchased the 2 amp boards and the cap coupling board from the GB, because I have Project 16 psu's, CRCRC psu's, LT4320 psu's, and the SLB's. I figured one would work for powering the F3 clone.
Thinking I will cool my jets as far as the F3 goes and finish my work on the preamps and the Nirvana. When I get around to building the F3, I will immerse myself in the thread and go from there.
From your last post 1594, it sounds like the F3 can be powered by 1 SLB, correct or not correct?
Thanks,
MM
F3 is single rail so you will want to use a single rail SLB. One SLB can handle up to 5A and so can power a stereo amp if each channel is under 2.5A. I would recommend two SLB’s each powered by their own trafo secondary winding. Could be single trafo though.
However, powering two stereo channels from a single SLB supply will have some crosstalk due to power rail sharing modulation. This crosstalk can be reduced by adding a separate CRC bank for each channel to help “stiffen” the rail for each channel and introduce more isolation, but fed from a common SLB. This will improve stereo separation for better imaging and sound stage.
However, powering two stereo channels from a single SLB supply will have some crosstalk due to power rail sharing modulation. This crosstalk can be reduced by adding a separate CRC bank for each channel to help “stiffen” the rail for each channel and introduce more isolation, but fed from a common SLB. This will improve stereo separation for better imaging and sound stage.
Hi X,
Thanks for chiming in. So here is the situation:
I have 2 SLB dual rail pcbs. My plan was to use 1 of them for the Alpha Nirvana build, using 1 large transformer as you built. So this would leave me with 1 dual rail pcb in the stable for a future stereo build , or, I use both SLB for the Nirvana and build a dual mono. Mucho dinero for dual mono, but maybe well worth it.
For the F3, it would make sense to use 2 single rail SLB and make a choice between 1 or 2 transformers. This is in the future, as I have other projects in the que.
Recommendations and comments are appreciated,
Thanks for chiming in. So here is the situation:
I have 2 SLB dual rail pcbs. My plan was to use 1 of them for the Alpha Nirvana build, using 1 large transformer as you built. So this would leave me with 1 dual rail pcb in the stable for a future stereo build , or, I use both SLB for the Nirvana and build a dual mono. Mucho dinero for dual mono, but maybe well worth it.
For the F3, it would make sense to use 2 single rail SLB and make a choice between 1 or 2 transformers. This is in the future, as I have other projects in the que.
Recommendations and comments are appreciated,
Myles,
Personally with that choice, I would go with two dual rail SLB’s for the Nirvana and build it with either a large single toroid or dual toroids.
And for the F3, I would do the same, except use two single rail SLB’s.
Anything less, and I would be tearing it apart and upgrading the build anyway, so why bother?!
If anybody has F3 blank pcb’s hanging around, send me a pm! Last night, I perused the circuit and it’s pretty cool with cascodes, LU1014 Jfets and such.
Best,
Anand.
Personally with that choice, I would go with two dual rail SLB’s for the Nirvana and build it with either a large single toroid or dual toroids.
And for the F3, I would do the same, except use two single rail SLB’s.
Anything less, and I would be tearing it apart and upgrading the build anyway, so why bother?!
If anybody has F3 blank pcb’s hanging around, send me a pm! Last night, I perused the circuit and it’s pretty cool with cascodes, LU1014 Jfets and such.
Best,
Anand.
Thanks Anand, my thoughts exactly. Will carry on. Parts supplies are crazy. One carrier sent my shipment to the wrong country and now I have to re-order😡.
All the best
All the best
The LuFo amp has cascodes and LU1014 JFET plus an inductor for more output swing. I have plenty of LuFo PCBs available.
https://www.diyaudio.com/community/threads/lufo-amp-39w-se-class-a-from-28v-rail.372679/
Here is a basic LuFo build (by Vunce) with SLB, power trafo, and MOT for the inductive load. You can also use many of the Hammond options like 193V etc.