Hi Vunce,
I think a 50v trafo will work fine as that is good for 70vdc on the FE stage and that should be enough of a difference for a 63v (200w) power stage. The place that it will matter is when playing full power as it is meant to drive the outputs without itself hitting clip.
Speaking of FE’s - the revised v002 FE PCBs just arrived today. These have the layout connection error fixed.
I think a 50v trafo will work fine as that is good for 70vdc on the FE stage and that should be enough of a difference for a 63v (200w) power stage. The place that it will matter is when playing full power as it is meant to drive the outputs without itself hitting clip.
Speaking of FE’s - the revised v002 FE PCBs just arrived today. These have the layout connection error fixed.
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This is going to be fun. I wonder if I should invest in a Variac for first start up to avoid magic smoke from blowing out of those expensive latFETs? I usually use a series 10ohm 10W resistor on the rails between the PSU and the amp, but here, the PSU rails are integrated with the amp and there is no separate place other than to change the R in the CRC it a big 10ohm. Or use a light bulb tester setup.
Yeah, I always use a variac for first power up, It’s a handy tool to have.
Even with your monster donut (trafo) collection there are times you just don’t have the “right” one, use the variac to dial in the voltage needed to test your circuit
Do you think the FE psu would benefit from being regulated?
Even with your monster donut (trafo) collection there are times you just don’t have the “right” one, use the variac to dial in the voltage needed to test your circuit
Do you think the FE psu would benefit from being regulated?
A case of regulitus I see.
I suppose regulated is not as important as ripple free. The front end probably has a very high PSRR already, but it never hurts to smooth it as much as possible. However, the built in PSU won’t let you do that unless you bypass it and send it your own regulated +/-70v supply. Another way is to use a small MHz DC-DC isolated output switching supply. Those usually have regulation to provide a set voltage.
I am going to see how quiet the standard configuration is before messing with it.
@Keantoken, what do we need to do to run the front end stand-alone today test it out first? Besides providing PSU rails, do we need to connect output to feedback node etc? I want to get this thing to run as a stand-alone preamp capable of +/-70v swings into a 10k load before I use it with the power stage.
I suppose regulated is not as important as ripple free. The front end probably has a very high PSRR already, but it never hurts to smooth it as much as possible. However, the built in PSU won’t let you do that unless you bypass it and send it your own regulated +/-70v supply. Another way is to use a small MHz DC-DC isolated output switching supply. Those usually have regulation to provide a set voltage.
I am going to see how quiet the standard configuration is before messing with it.
@Keantoken, what do we need to do to run the front end stand-alone today test it out first? Besides providing PSU rails, do we need to connect output to feedback node etc? I want to get this thing to run as a stand-alone preamp capable of +/-70v swings into a 10k load before I use it with the power stage.
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You could at least make a dim bulb tester for almost nothing as a precaution for anything you turn on the first time. Both is nice.
The trafo's are here. One never fully appreciates the sheer size and weight of a 600VA trafo. This is AN-6458.
I placed my order to Mouser for the BOM for the FE. $36/ch - not bad at all. I am thinking that the FE board might make a very nice and powerful preamp board for driving 0dB gain amps that need lots of swing.
I placed my order to Mouser for the BOM for the FE. $36/ch - not bad at all. I am thinking that the FE board might make a very nice and powerful preamp board for driving 0dB gain amps that need lots of swing.
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I made some progress in October assembling the FE boards but my work has gotten so busy the project has stalled.
Here are the assembled FE boards:
I was considering this for a chassis and the color is fitting. The question is will it be big enough to hold the MB's on the heatsink with the FE boards sticking into the main cavity with dual 600VA trafos? Seems tight.
Full aluminum amplifier chassis / Class A amplifier / After class / tube AMP / AMP Enclosure / case / DIY box (430*200*375mm)|Amplifier| - AliExpress
Luckily, I was able to ask Vunce and he agreed to help me assemble the verification build. Now, I need to ship him 28lbs of trafos and the FE boards and all the Exicons.
Thank you Vunce! We will see progress once again as soon as his bench clears of the current preamp project.
Here are the assembled FE boards:
I was considering this for a chassis and the color is fitting. The question is will it be big enough to hold the MB's on the heatsink with the FE boards sticking into the main cavity with dual 600VA trafos? Seems tight.
Full aluminum amplifier chassis / Class A amplifier / After class / tube AMP / AMP Enclosure / case / DIY box (430*200*375mm)|Amplifier| - AliExpress
Luckily, I was able to ask Vunce and he agreed to help me assemble the verification build. Now, I need to ship him 28lbs of trafos and the FE boards and all the Exicons.
Thank you Vunce! We will see progress once again as soon as his bench clears of the current preamp project.
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Looking forward to Vunce's build and verification. I am also hoping for a slightly scaled down version, like 100 watts instead of 300 watts.
Although I have built a dim bulb tester, I use this Variac all the time:
Bench Top 20 Amp Variac Variable Auto-Transformer with LCD Digital Display
Best,
Anand.
Although I have built a dim bulb tester, I use this Variac all the time:
Bench Top 20 Amp Variac Variable Auto-Transformer with LCD Digital Display
Best,
Anand.
I have some good news: after a long hiatus, the Aurum-X project is finally going to get some TLC as a member has volunteered to be a verification builder. I am simply too busy lately with commercial projects to work on a complex project like this. This person has already put together a Mouser order, ordered the trafo, and about to order the lateral MOSFETs from Profusion. Anyhow, good to see this very interesting project back on the saddle.