To Stuart: thanks for your clear explenation; my heatsinks are big enough (i bougth them second hand); they are made for connecting 12cmx12cm fan's witch i decide to mount only when it runs to hot. Thanks again.
To Jan: thanks for your effort to make a revised lay-out!
To Coulomb: i bought the toroids second hand for a very good price, thats why i use them.
To Jan: thanks for your effort to make a revised lay-out!
To Coulomb: i bought the toroids second hand for a very good price, thats why i use them.
K-amps, the second fix (pot R105) is for the same reason as the other fix for so far as i can see.
Preparing for making the amp i have a view more questions:
I see 1 feedback connection on the mainboard. Do i have to connect it to one off the output connections from both outputboards? (so 2 wires from 1 feedback connectionpoint?
What are the specifications of L201 (I, mH)? And by the way, were is L201 and R206 for? If i dont use the optional L201 and R206, do i have to use R205 and C201?
D201 and D202 are not on the boards. Must i use them? And were are they for?
What is the best place to connect the GND wire of the speaker terminals? I think not that connection with the input GND is the best way (power GNO on signal GND).
Many questions, i know. Maybey some of these questions are interesting for more board-owners (i hope).
I see 1 feedback connection on the mainboard. Do i have to connect it to one off the output connections from both outputboards? (so 2 wires from 1 feedback connectionpoint?
What are the specifications of L201 (I, mH)? And by the way, were is L201 and R206 for? If i dont use the optional L201 and R206, do i have to use R205 and C201?
D201 and D202 are not on the boards. Must i use them? And were are they for?
What is the best place to connect the GND wire of the speaker terminals? I think not that connection with the input GND is the best way (power GNO on signal GND).
Many questions, i know. Maybey some of these questions are interesting for more board-owners (i hope).
wim:
The feedback comes in one wire from the center between the positive and negative Emittor resistors.
L201 should be app. 5uH/R210 10R
L201 and R210 are there to protect the output devices (all loads are inductive/capacative)....
R201/C201 are the Zobel filter to prevent the amp from oscillating!
D201/D202 are there to protect the output devices, when driving inductive/capacitive loads.
GND wire from speaker terminals should go directly to the main GND-connection between the PSU caps/Center of toroid.
The feedback comes in one wire from the center between the positive and negative Emittor resistors.
L201 should be app. 5uH/R210 10R
L201 and R210 are there to protect the output devices (all loads are inductive/capacative)....
R201/C201 are the Zobel filter to prevent the amp from oscillating!
D201/D202 are there to protect the output devices, when driving inductive/capacitive loads.
GND wire from speaker terminals should go directly to the main GND-connection between the PSU caps/Center of toroid.
Thanks jan.
You said that the feedback comes in one wire form the center (of the mainboard) between the positive and negative emittor resistors; i can see on the schematic what you mean.
But the positive emmitor resistors and the negative emmitor resistors are not located on the same outputboard. So i still dont anderstand it.
You said that the feedback comes in one wire form the center (of the mainboard) between the positive and negative emittor resistors; i can see on the schematic what you mean.
But the positive emmitor resistors and the negative emmitor resistors are not located on the same outputboard. So i still dont anderstand it.
ANTHONY2181 said:
Anthony, All your questions of your can be answered with a YES. (except for the Q3 because I am not aware of those devices). However your amp will not be a Krell clone, it will be A "Tony's Remix"
😀
As for heatsinking, everyone is using their own types. with Qbias mounted on the heatsinks. As for your Trafo, 40-0-40 will work, however your amp will need to be biased lower, otherwise you will get a KSA-150 with those rails. And the 6 OP devices might be stressed a lot.
Hi,
Thanks K-Amps
I think i'll add some turns to reduce the voltage a little 30 0 30 or
35 0 35 sounds better.A KSA-150 sounds nice but a lot of heat.
Thanks Again
Anthony
Thanks K-Amps
I think i'll add some turns to reduce the voltage a little 30 0 30 or
35 0 35 sounds better.A KSA-150 sounds nice but a lot of heat.
Thanks Again
Anthony
actually...
The secondary will be wound on top, so to reduce the secondary voltage you will want to reduce the number of turns...Depending on how the transformer is wound you may need to completely unwind the secondary, I've had to do this a couple of times over the last couple of weeks...it's easy, but not a lot of fun.
FYI 30-0-30 is still way too high for a ksa50, 24-0-24 is more like it...with 30-0-30 you will get 44v rails and if you bias it at 2-3 amps you'll need 4 (to3) or 6(to3p) output pairs and huge (0.1c/w heatsinks) per channel.
Basically everything you are asking has been covered in the thread, some items many times over, best plan is just to invest a little time and read, it'll save some expensive mistakes later on.
I am heading over to england in the next month or so, if you are going to make one of these I am bringing over emitter resistors for another member that is near where my parents live, and will happily include some for you, just let me know how many.
Stuart
The secondary will be wound on top, so to reduce the secondary voltage you will want to reduce the number of turns...Depending on how the transformer is wound you may need to completely unwind the secondary, I've had to do this a couple of times over the last couple of weeks...it's easy, but not a lot of fun.
FYI 30-0-30 is still way too high for a ksa50, 24-0-24 is more like it...with 30-0-30 you will get 44v rails and if you bias it at 2-3 amps you'll need 4 (to3) or 6(to3p) output pairs and huge (0.1c/w heatsinks) per channel.
Basically everything you are asking has been covered in the thread, some items many times over, best plan is just to invest a little time and read, it'll save some expensive mistakes later on.
I am heading over to england in the next month or so, if you are going to make one of these I am bringing over emitter resistors for another member that is near where my parents live, and will happily include some for you, just let me know how many.
Stuart
Anthony:
I am one of the people going with a "high" voltage (28vac) toroid, i too am using 800va toroids, but i have to use BIG heatsinks (i'm talking fan forced 0.2w/c heatsinks!) and also 5 pairs of output devices per channel.... (3 channels)... Making a KSA-100 or 150 sounds great, but it's going to have to have a lot of things brought into the equation...
If you search through some of my posts and stuarts (and others) reply's you should find 90% of all the answers you are after. And i believe too that you will have to unwind your toroid to get the right voltages, how far, i'm not sure!
It really depends on how far you want to run the amp into class a as well...
We've had the discussion previously over why the KSA-50 is 'better sounding' than the KSA-100, considering the amps are almost identical in every way, people think it may be connected to the lower rail voltage...>
Something to think about!
Aaron
I am one of the people going with a "high" voltage (28vac) toroid, i too am using 800va toroids, but i have to use BIG heatsinks (i'm talking fan forced 0.2w/c heatsinks!) and also 5 pairs of output devices per channel.... (3 channels)... Making a KSA-100 or 150 sounds great, but it's going to have to have a lot of things brought into the equation...
If you search through some of my posts and stuarts (and others) reply's you should find 90% of all the answers you are after. And i believe too that you will have to unwind your toroid to get the right voltages, how far, i'm not sure!
It really depends on how far you want to run the amp into class a as well...
We've had the discussion previously over why the KSA-50 is 'better sounding' than the KSA-100, considering the amps are almost identical in every way, people think it may be connected to the lower rail voltage...>
Something to think about!
Aaron
I'm now sulking, 'cos I had a 30-0-30 shielded, encapsulated 750VA jobbie just waiting for a project like this. Oh well, time to find some bigger heatsinks... 🙁
pinkmouse said:
Definately use it! It was what i was going to was originally, but with the bias i'm running (about 150w into 4 ohm @ class A would be doable!!) i'll need 0.1c/w heatsinks at least for ambient cooling... 🙂 i believe mine are actually 0.25c/w and fan cooled 🙂
Aaron
Hi All-
I just found a source for BIG and what I consider pretty heat sinks.
I was having an enclosure Anodized when I saw them and asked where they were from.
M&M Metals in Irving TX(part of DFW).
I will be calling for prices next week. When I pick up my enclosure I will take a picture of the heat sinks that were there since I did NOT see them on the web site.
mmmetals.com
They "looked" to be 12" wide x 16" tall x 1.5" deep. the fins were 1 -1.25" tall on a .25 - .50" base. All fins were rounded so NO SHARP edges.
More info to come next week when I call and then go by.
Edit-
I may have custom enclosures made for my KSA-50 and if so it is always cheaper to have more than one made. Chassis GB for the KSA-50?
Here is a picture of my gain clone chassis I had made.
I just found a source for BIG and what I consider pretty heat sinks.
I was having an enclosure Anodized when I saw them and asked where they were from.
M&M Metals in Irving TX(part of DFW).
I will be calling for prices next week. When I pick up my enclosure I will take a picture of the heat sinks that were there since I did NOT see them on the web site.
mmmetals.com
They "looked" to be 12" wide x 16" tall x 1.5" deep. the fins were 1 -1.25" tall on a .25 - .50" base. All fins were rounded so NO SHARP edges.
More info to come next week when I call and then go by.
Edit-
I may have custom enclosures made for my KSA-50 and if so it is always cheaper to have more than one made. Chassis GB for the KSA-50?
Here is a picture of my gain clone chassis I had made.
Attachments
I bought heat sinks for my Aleph 2's fomr M&M Metals. The fuys down there were VERY nice to work with and seem to cater to the DIY'er. My sinks are the same as are on the Krell KSA-80 except I have six on my 2's. Total cost with shipping for 12 of them was about 325.00 unanodized. I reccomend getting them unanodozed and doing all your machining first, then anodizing when you're done.
Mark
Mark
Does any one else notice some discrepancies between the schematic parts number/published parts list and the board?
D201,202=?
D305,306=?
R303,304,305,306=?
R201,,202,203,204=?
Prosit
D201,202=?
D305,306=?
R303,304,305,306=?
R201,,202,203,204=?
Prosit
Yes, there seems to be but its easy to figure out where the parts go by just tracing the board. hings are also symetrical to a point which makes it easy.
Mark
Mark
Certainly. Now, does anyone know the values of the components mentioned? Seems they are not on the "Suggested Components List" posted on delta-audio.com 
Is there another source for a correct parts list that I'm missing?
D201,202=what value?
D305,306=what value?
R303,304,305,306=what value?
R201,202,203,204=what value?
Sorry to press the point and my eyesight ain't what it used to be, but I read OK and don't see these components on the parts list, nor their value. Can anyone help an old geezer
get the right parts?
Kinda want to get on with soldering.
Prosit
Is there another source for a correct parts list that I'm missing?
D201,202=what value?
D305,306=what value?
R303,304,305,306=what value?
R201,202,203,204=what value?
Sorry to press the point and my eyesight ain't what it used to be, but I read OK and don't see these components on the parts list, nor their value. Can anyone help an old geezer
get the right parts?Kinda want to get on with soldering.
Prosit
acenovelty said:
D201,202=what value?
D305,306=what value?
R303,304,305,306=what value?
R201,202,203,204=what value?
Sorry to press the point and my eyesight ain't what it used to be, but I read OK and don't see these components on the parts list, nor their value. Can anyone help an old geezer
Kinda want to get on with soldering.
Prosit
It's just a mismatch with the labelling.... D201/202 should be 1N5059 if i am correct
D305/306 should be 1N4148 if i am correct also
(oh, and half the parts you mention "*3**" are all for output protection circuit, so no loss if they don't exist, unless you want one!
R303/304/305/306 should be 100R for a safe SOA (according to the spec sheet)
R201/202/203/204 should be pretty much what you like, they are emittor resistors... i'm going for 0.68R others are going for 0.5, some for 1R, up to you really (what do you have lying around?!)
Hope this helps a little
Aaron
Found an old parts list lurking deep in my system from Nov. 23, 2004 that seems more accurate than the current listing. But it is too big to attach on this page. Pity. Maybe some one can be convinced to post a more accurate parts list.
For those of you who want to build with TO3 instead of plastic transistors, the correct parts are MJ15003 and MJ15004 instead of the MJL21193/4.
Prosit
For those of you who want to build with TO3 instead of plastic transistors, the correct parts are MJ15003 and MJ15004 instead of the MJL21193/4.
Prosit