and I was going to use a redundant aluminium heatsink as a "jig" to drill out the To3 holes.
unsigned (too ashamed)!
unsigned (too ashamed)!
Exactly. Fixtures are still very useful but have a finite life span.
Andrew... You could use that TO-3 heatsink to lay out your jig or fixture since it was accurately done... probably by CNC.
Mark
Andrew... You could use that TO-3 heatsink to lay out your jig or fixture since it was accurately done... probably by CNC.
Mark
PCB
Hi,
If I am late never mind! If I'm not, would be interested for board.
Thanks in any case!
Hi,
If I am late never mind! If I'm not, would be interested for board.
Thanks in any case!
Yep, your late Kusta,
or anyone else interested, for that matter...
Feel free to replace my name with yours in the Wiki. I have money flowing in other places at the moment and another amp build won't happen for a while....
maybe next year🙂
or anyone else interested, for that matter...
Feel free to replace my name with yours in the Wiki. I have money flowing in other places at the moment and another amp build won't happen for a while....
maybe next year🙂
Quiet here lately..
Well I've updated the BOM with a few changes and elaborations, plus added quite an extensive Everything You Need To Know About The KSA100 Clone But Too Afraid To Ask section. It's not the basic assembly instructions, but more directly applicable to the KSA100 Mk2 and the boards and can be seen as a parahrased version of most of what has been covered on the thread so far.
Combined with the KSA50 wiki instructions it should be very easy to build.
Any comments or additions will be appreciated 🙂
[There were some errors with the jumper designators that are fixed now]
Well I've updated the BOM with a few changes and elaborations, plus added quite an extensive Everything You Need To Know About The KSA100 Clone But Too Afraid To Ask section. It's not the basic assembly instructions, but more directly applicable to the KSA100 Mk2 and the boards and can be seen as a parahrased version of most of what has been covered on the thread so far.
Combined with the KSA50 wiki instructions it should be very easy to build.
Any comments or additions will be appreciated 🙂
[There were some errors with the jumper designators that are fixed now]
Payment
Mark
I've made a payment - please check if it has arrived on your side ?
Many thanks for the willingness to assist in having the boards made. I have never seen a project move so fast.
Jozua
Mark
I've made a payment - please check if it has arrived on your side ?
Many thanks for the willingness to assist in having the boards made. I have never seen a project move so fast.
Jozua
PWatts,
I disagree to your comment regarding the 5 Amp bias set level of the mk-II
. Proper bias set level should be 2.5-2.8 Amps depending on % of margin. If you meant 5 Amp peak level I agree to you but what you have specified in the BOM document could be confusing to somebody not familiar to Class-A calculation.
Here I would like to refer to some of the earlier posts designated K-Amps, AndrewT and Stuart, whom discussed the subject and cleared things out:
Further information on this subject is to be find in Post # 96-102
Regards 😎
I disagree to your comment regarding the 5 Amp bias set level of the mk-II
. Proper bias set level should be 2.5-2.8 Amps depending on % of margin. If you meant 5 Amp peak level I agree to you but what you have specified in the BOM document could be confusing to somebody not familiar to Class-A calculation. Here I would like to refer to some of the earlier posts designated K-Amps, AndrewT and Stuart, whom discussed the subject and cleared things out:
Further information on this subject is to be find in Post # 96-102
Regards 😎
This thread has been quiet
I have not checked this board or any prior messages but does anyone knows if the pc boards have been ordered and if there is a delivery schedule?
Thanks
I have not checked this board or any prior messages but does anyone knows if the pc boards have been ordered and if there is a delivery schedule?
Thanks
Yes! Boards were ordered on the 1st of DEC with a 4 week turn= around(the cheapest route). With the holidays I expect to do the shipping after Christmas and between New Years as long as delivery is not held up by the holidays. I will post when the boards arrive here and are shipped and so on.
Mark
Mark
Flodstroem,
As with all bias issues it's always confusing how people refer to it. With 5A I meant in total from the supply i.e. both rails. At 2.5A per rail, it gives 5A total, or 620mA x 8 output devices.
As with all bias issues it's always confusing how people refer to it. With 5A I meant in total from the supply i.e. both rails. At 2.5A per rail, it gives 5A total, or 620mA x 8 output devices.
Hi Pwatts,
if you want to refer to bias your way then spell it out each time to avoid confusion.
This is the method used in the spreadsheet but it is quite unconventional.
if you want to refer to bias your way then spell it out each time to avoid confusion.
This is the method used in the spreadsheet but it is quite unconventional.
OK OK fine.. but it should be clear to figure out anyway since the total bias is after all the total bias per transistor added together.. and knowing it's 620mA each it's not rocket science.
From a heatsink perspective it makes sense to refer to the total bias since that is what the sink needs to dissipate, but from the amp side the per rail value is more sensible.
Besides, anyone building the amp should at least know the basics of how to calculate reasonable values for 100W into 8ohms or it's likely to blow up anyway
From a heatsink perspective it makes sense to refer to the total bias since that is what the sink needs to dissipate, but from the amp side the per rail value is more sensible.
Besides, anyone building the amp should at least know the basics of how to calculate reasonable values for 100W into 8ohms or it's likely to blow up anyway
Once again, anyone that is a late-comer that would like a couple of boards just needs to dial into the WIKI and replace my name with thiers.🙂
PWatts said:
Heatsink dissipates power, not current. Bias current flows from +Ve to -Ve, and it is regulated at one single point (Vbe multiplier). It makes much more sense to me to say that my amp runs 2A idle current at +/- 50V (that is 200 watts of power to be turned out into heat) rather than say I've got 4A idle. I mean, if you measure current anywhere in the circuit, there is no one single point where your ammeter will show 4A, is it ? Same current flows through both branches of output - you can't add them. But you can add voltage, 'cause between +V and -V you do have 2 times 50 volts. The voltmeter will measure 100V between rails. I think it is a bit more than just semantics.
Bratislav
Jeez OK I should've stuck to the conventional format I suppose.
Heatsinks do of course disssipate power - but with the voltage a fixed parameter (well hopefully with a proper transformer anyway), current increase will increase power in direct proportion so there's nothing wrong with that statement.
Heatsinks do of course disssipate power - but with the voltage a fixed parameter (well hopefully with a proper transformer anyway), current increase will increase power in direct proportion so there's nothing wrong with that statement.
don't feel bad...
...there is no single answer that will suffice for all people and all possibilities...and it's clear your answer will have answered some peoples unspoken questions...
Power in the heatsink is a big deal for this amp, giving people more info may help them understand what's proportional to what and thereby gain better insight into their particular build. This is unambiguously a good thing...
...and this is key; except for exact clones, there is a good chance no two of these amps are the same, thus each builder/designer must understand the heat issues, they need to make adjustments and end up with a stable, reliable amp.
I expect we will see the same questions many more times before we are done, and answering them different ways, from different perspectives is needed to give everyone the best chance of understanding...
Stuart
...there is no single answer that will suffice for all people and all possibilities...and it's clear your answer will have answered some peoples unspoken questions...
Power in the heatsink is a big deal for this amp, giving people more info may help them understand what's proportional to what and thereby gain better insight into their particular build. This is unambiguously a good thing...
...and this is key; except for exact clones, there is a good chance no two of these amps are the same, thus each builder/designer must understand the heat issues, they need to make adjustments and end up with a stable, reliable amp.
I expect we will see the same questions many more times before we are done, and answering them different ways, from different perspectives is needed to give everyone the best chance of understanding...
Stuart
thats easy...
2.9 amps, 57 volt rails == 330 watts per channel, with 30c temp rise...you need heatsinking to the tune of 0.091c/watt, per channel.
To give (computer geeks) an idea of what that translates to: A stock P4 cooler (with fan) supplied by intel is slightly better than 0.5c/w, so minimally you'd need 6 of them per channel, with their fans...perhaps 8 might be better, one per transistor...of course 8 fans would be kind of loud...
Unfortunately CPU heatsinks are designed to use fans, they are much less efficient without them...
http://www.overclockers.com/articles373/socketA.asp
Stuart
2.9 amps, 57 volt rails == 330 watts per channel, with 30c temp rise...you need heatsinking to the tune of 0.091c/watt, per channel.
To give (computer geeks) an idea of what that translates to: A stock P4 cooler (with fan) supplied by intel is slightly better than 0.5c/w, so minimally you'd need 6 of them per channel, with their fans...perhaps 8 might be better, one per transistor...of course 8 fans would be kind of loud...
Unfortunately CPU heatsinks are designed to use fans, they are much less efficient without them...
http://www.overclockers.com/articles373/socketA.asp
Stuart