I was always unsure about using Peter's boards. Doesn't seem like there is good separation for heat dissipation. I will be interested to see if it feels like the heat is concentrated on your heat sinks with the middle being warmer than the ends. Looking forward to the results as I never went through with the project.
Well, the majority of my power devices will be on their own heatsink, connected to the PCB via an umbilical. (or extension wires, if you want to call them that.) I think the stock configuration of his board would be fine if you had one really big linear heatsink.
Which spacing is there between the mosfets tightening screws ?
Extra wires should do, but careful with unwanted oscilations (long leads)
Best,
nAr
Extra wires should do, but careful with unwanted oscilations (long leads)
Best,
nAr
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What is the power supply voltages and current requirements?
Looks like R3 needs to be grounded for single-ended operation.
Looks like R3 needs to be grounded for single-ended operation.
PSU will be a variation of 'Zen Vernacular", which is to say 18v+18v 400va, 2 full wave bridges and CRC with about 120,000uf per rail.
Look at an F5 PSU and double the capacitance. That's the template I'm working from.
Look at an F5 PSU and double the capacitance. That's the template I'm working from.
well its normally built with only 2 pairs, the third is there if you want, but the standard design only has 2 in use
That's how I am going to use it - 2 IRF240's for the Aleph current sources and 2 R100's for the output.
yeah thats what i figured, so there should be no issue with uneven heat dissipation. i have a set of boards stuffed bar the fets with very similar parts: silmics, mills, a couple of zfoils for good luck, prp, caddock but with cornell dubilier smd RF teflon 4.7pf caps in the input filter in place of the ceramic caps.
so i'm watching your build with great interest as i had planned to try and do this myself, but was a little unsure of how to handle the R100 bias. you are building single ended mono blocks though aren't you? i'm trying for x'd so could be a bit more touchy, but setup should be roughly the same. i really do need a scope though i'm realising.
so i'm watching your build with great interest as i had planned to try and do this myself, but was a little unsure of how to handle the R100 bias. you are building single ended mono blocks though aren't you? i'm trying for x'd so could be a bit more touchy, but setup should be roughly the same. i really do need a scope though i'm realising.
qusp -
I'm actually building a stereo amp in the image of the original Aleph.
As for biasing the R100, (I think, and anybody, please correct me if I am wrong) the bias is controlled by the resistor (now shown as a vey badly drawn potentiometer in my schematic) that connects V- to the gates of the R100. The 240's needed about 4v, the R100's about 1.2v .
So hopefully the substitution of that pot is all I need. Perhaps ZenMod or Nelson could chime in and shed a little light on it? 🙂 🙂
I'm actually building a stereo amp in the image of the original Aleph.
As for biasing the R100, (I think, and anybody, please correct me if I am wrong) the bias is controlled by the resistor (now shown as a vey badly drawn potentiometer in my schematic) that connects V- to the gates of the R100. The 240's needed about 4v, the R100's about 1.2v .
So hopefully the substitution of that pot is all I need. Perhaps ZenMod or Nelson could chime in and shed a little light on it? 🙂 🙂
That is correct. What Vgs it wants is a function of the individual fet, but i think you are in the right area based on what I have read. ITis generally in the area where the Fet is turned fully on. I think you are going to be surprised at the difference between it and your F5. I'll be interested in your opinions.
It's going to have more power supply, better output devices, a more unique name, and it's going to look a bunch better. But the last two are my opinion.
😀 😀 😀 😀 😀
😀 😀 😀 😀 😀
I love to speculate so I would guess it will sound more similar than different. The difference in sound will come from the slight difference in topology and how the Master chose to execute it.
I've listened to a bunch of SemiSouth variants of my own creation.
They alll sound diffferent to me. if there is a 'use' SemiSouth sound, it's a bit cleaner on the mid-top than an IRF240 IMO.
They alll sound diffferent to me. if there is a 'use' SemiSouth sound, it's a bit cleaner on the mid-top than an IRF240 IMO.
A quick update to the project that is flowing along like cold molasses --
I finally found a machinist that is the type of guy I am looking for! (One man shop, understands prototyping, can get the idea out of my horrible sketches, etc...)
So now I need to make one last order to get some fancy-pants binding posts and XLR jacks, bring all the pieces to the machinist and the box will be built!
This may sound boring, but it's actually a giant leap forward for this project.
😀 😀 😀 😀 😀
I finally found a machinist that is the type of guy I am looking for! (One man shop, understands prototyping, can get the idea out of my horrible sketches, etc...)
So now I need to make one last order to get some fancy-pants binding posts and XLR jacks, bring all the pieces to the machinist and the box will be built!
This may sound boring, but it's actually a giant leap forward for this project.
😀 😀 😀 😀 😀
Depends on what you wanted, a fair number of machinist don't do one off stuff or will quote you extra high for the work. Mostly the setup takes all the time, the actual machine work doesn't take all that long. I pretty much only do one off projects and have small shop and rely on the fact that most of the biggers just won't do what I do. It's just because I hate repetitive work 🙂.
The cost is directly proportional to how much work you do beforehand. In general, you will want to start with your heatsinks and build around them. Just showing up with a photo of an old Krell and asking a machineshop to build it? You might as well just buy the old Krell and yank all the guts from it...
(Yes, I know that is a serious non-answer answer. Sorry...)
The best advice is to find a one-man shop. As soon as a boss has to send it to the floor and have somebody else make it, the cost is at least double.
(Yes, I know that is a serious non-answer answer. Sorry...)
The best advice is to find a one-man shop. As soon as a boss has to send it to the floor and have somebody else make it, the cost is at least double.
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