Hi All-
I was checking on the wife and her kitting activities and came across the diode that was ordered for the kit.
Mouser Part # 512-1N4148
Fairchild Semiconductor
Description: Fairchild Diodes DO-35 100V Io/200mA BULK
Is 200mA sufficient for this application?
The 27v Zeners are 500mA. I am not having any luck finding a "beefier" diode on Mouser's site.
Comments?
And for those concerned, the wife does not work so this is keeping her butt home and from shopping!...
EDIT: We have still not received all the Welborne Labs parts... We are just starting the kitting so when they do arrive we can ship out.
I was checking on the wife and her kitting activities and came across the diode that was ordered for the kit.
Mouser Part # 512-1N4148
Fairchild Semiconductor
Description: Fairchild Diodes DO-35 100V Io/200mA BULK
Is 200mA sufficient for this application?
The 27v Zeners are 500mA. I am not having any luck finding a "beefier" diode on Mouser's site.
Comments?
And for those concerned, the wife does not work so this is keeping her butt home and from shopping!...
EDIT: We have still not received all the Welborne Labs parts... We are just starting the kitting so when they do arrive we can ship out.
IN4148s are what I'm using, and work fine.
I'm using 1A Motorola zeners, I'm suprised you can't find higher...
:edit: here you go;
http://www.mouser.com/index.cfm?han...uctid=209884&e_categoryid=237&e_pcodeid=51233
I'm using 1A Motorola zeners, I'm suprised you can't find higher...
:edit: here you go;
http://www.mouser.com/index.cfm?han...uctid=209884&e_categoryid=237&e_pcodeid=51233
Hi Rabstg,
I think you have got your units mixed up.
27V and 500mA =13.5W and 100V and 200mA =20W. These sizes of Zeners do not suit the KSA Klone.
The Zeners can be 400mW or 500mW. I believe these would be better than using 1000mW or 3W because it is recommended that the minimum current through the Zener should be at least 10% of it's maximum rating. A 27V 500mW device requires a minimum current >=1.85mA.
The Zener bleeds off excess current after passing through the dropper resistor (r108=1k5) which at about 3.7mA is 20% of rating. R108 will run hot and it's value could be raised slightly without interfering with the performance, maybe as high as 2k2 on 38Vrails.
I think you have got your units mixed up.
27V and 500mA =13.5W and 100V and 200mA =20W. These sizes of Zeners do not suit the KSA Klone.
The Zeners can be 400mW or 500mW. I believe these would be better than using 1000mW or 3W because it is recommended that the minimum current through the Zener should be at least 10% of it's maximum rating. A 27V 500mW device requires a minimum current >=1.85mA.
The Zener bleeds off excess current after passing through the dropper resistor (r108=1k5) which at about 3.7mA is 20% of rating. R108 will run hot and it's value could be raised slightly without interfering with the performance, maybe as high as 2k2 on 38Vrails.
Mouser Part #: 512-BZX55C27
Mfr. Part #: BZX55C27
Mfr.: Fairchild Semiconductor
Description: Fairchild Zener Diodes DO-35 27V, 0.5W Zener - RoHS non-compliant/CONTAINS Pb
That is the Zener I ordered/received.
The question was for the 1N4148 diode Not the Zener.
Mouser Part # 512-1N4148
Fairchild Semiconductor
Description: Fairchild Diodes DO-35 100V Io/200mA BULK
Is 200mA large enough?
EDIT:
TO BE CLEAR, the issue is NOT with the 27V Zener, but the other diodes in the BOM.
Mfr. Part #: BZX55C27
Mfr.: Fairchild Semiconductor
Description: Fairchild Zener Diodes DO-35 27V, 0.5W Zener - RoHS non-compliant/CONTAINS Pb
That is the Zener I ordered/received.
The question was for the 1N4148 diode Not the Zener.
Mouser Part # 512-1N4148
Fairchild Semiconductor
Description: Fairchild Diodes DO-35 100V Io/200mA BULK
Is 200mA large enough?
EDIT:
TO BE CLEAR, the issue is NOT with the 27V Zener, but the other diodes in the BOM.
Howdy lgreen,
Many thanks for the honorable mention in the build wiki, and Mr. loek seems to have posted this info up loooong ago. Certainly did not intend to steal his thunder. And let's not forget Mr. Easson who provides invaluable information on many subjects.
When we get further along with the build I will give some better info about passive cooling results in the wiki. But, I don't work as fast as some folks here. And this is a learning experience for my teenager on the weekends. (Well, me also) Kinda important that he pretty much makes every part of this amp from scratch cause he wants to know how.
On the subject of a self made driver board, will a 1 oz. copper board be good enough to carry the voltage/current given wide traces? Indeed, is 1 oz. good enough for Mr. Pinkmouse's creation?
Mr. Puunda, jacco vermeulen makes all the salient points for your decision except for the part about the necessity for some "skills" related to actually making something and the pride of creation and of ownership. And of course, bragging rights. Time and money and cheap? Pick one, maybe two, but all three is not very likely in my humble opinion and experience. Something my 16 year old is learning from this project along with the virtue of patience, the value of persistence and the importance of precision.
Regards,
Elvin
Many thanks for the honorable mention in the build wiki, and Mr. loek seems to have posted this info up loooong ago. Certainly did not intend to steal his thunder. And let's not forget Mr. Easson who provides invaluable information on many subjects.
When we get further along with the build I will give some better info about passive cooling results in the wiki. But, I don't work as fast as some folks here. And this is a learning experience for my teenager on the weekends. (Well, me also) Kinda important that he pretty much makes every part of this amp from scratch cause he wants to know how.
On the subject of a self made driver board, will a 1 oz. copper board be good enough to carry the voltage/current given wide traces? Indeed, is 1 oz. good enough for Mr. Pinkmouse's creation?
Mr. Puunda, jacco vermeulen makes all the salient points for your decision except for the part about the necessity for some "skills" related to actually making something and the pride of creation and of ownership. And of course, bragging rights. Time and money and cheap? Pick one, maybe two, but all three is not very likely in my humble opinion and experience. Something my 16 year old is learning from this project along with the virtue of patience, the value of persistence and the importance of precision.
Regards,
Elvin
Hi Elvin
If you keep the traces as thick as practical, then you should have no problem with 1oz copper, I suspect that's all they would have used on the original anyway.
Thanks for the intrinsic compliment, but this was a team effort!
Troy, 1N4148s are fine, no need to panic!
Puunda, If you want to buy something new, that's fine, but you ought to realise that as this is a diy site, replies will be naturally biased towards building something for yourself. Oh, and If I calculated what this project has cost me, in time alone at commercial rates then all the GBers owe me about $5000.
If you keep the traces as thick as practical, then you should have no problem with 1oz copper, I suspect that's all they would have used on the original anyway.
Thanks for the intrinsic compliment, but this was a team effort!
Troy, 1N4148s are fine, no need to panic!
Puunda, If you want to buy something new, that's fine, but you ought to realise that as this is a diy site, replies will be naturally biased towards building something for yourself. Oh, and If I calculated what this project has cost me, in time alone at commercial rates then all the GBers owe me about $5000.
a 1n4148 costs little, and is one of the fastests diodes.
If you go higher power, like 1n400*: more current, less speed.
Not better if there is no need, cheap can be best.
I'm sorry, i have been to nice lately:
Puunda: build, build, build, you lazy bum !
Find a rich bloke, you'll not get a penny out of me, Mr. Mouse.
If you go higher power, like 1n400*: more current, less speed.
Not better if there is no need, cheap can be best.
I'm sorry, i have been to nice lately:
Puunda: build, build, build, you lazy bum !
Find a rich bloke, you'll not get a penny out of me, Mr. Mouse.
On another note, somewhat odd.... I have a chance to run a fairly new 35mm print of "Forbiden Planet" this comming Saturday night for a large audience........ For those that are not aware this is the movie that features the "Krell People" and is where "Dan the man" got the name Krell.... perhaps taking part in this thread and running the movie are just all part of my destiny
... at the very least its certainly an odd coincidence!
Mark
... at the very least its certainly an odd coincidence!Mark
Today I bought 200 of the Thermalloy TO-247 Ceramic/Alumnium Oxide insulators. I will let you guys have them for my cost which was 50 cents (U.S.) each plus shipping plus PayPal 3%. Most places sell these for about .75 cents each. There is at least a bag of 1000 more available and I put a temporary hold on those till I see how many of these you guys buy..... if these go fast I will front the $500.00 to also get the bag of 1000. The specs are here.
So go ahead and PayPal me what you want. Shipping charges are below.... Add 3% to the total.
U.S. Priority 3.95
Foreign Priority 9.85... Italy and some other countries please check with me first as rates are higher.....
I am only offering these to KSA-50 builders at this time.....
Come and get em......
Mark
So go ahead and PayPal me what you want. Shipping charges are below.... Add 3% to the total.
U.S. Priority 3.95
Foreign Priority 9.85... Italy and some other countries please check with me first as rates are higher.....
I am only offering these to KSA-50 builders at this time.....
Come and get em......
Mark
Howdy Mr. rjkdivin/Robert,
Got to ask my boy about this to make sure about more of this size. I think he got the 2 of them from the local steel scrap yard. Seems like he mentioned that there were some other versions in the pile, but don't recollect for sure.
These were pre drilled and dirty with some surface scratches, but I suppose that won't hurt none. Think maybe he paid about $75 for them. Al stock sells for around $3.50 to $4.00 a pound at the yard and suspect the sink weighs about 9-10 pounds each.
Regards,
Elvin
Got to ask my boy about this to make sure about more of this size. I think he got the 2 of them from the local steel scrap yard. Seems like he mentioned that there were some other versions in the pile, but don't recollect for sure.
These were pre drilled and dirty with some surface scratches, but I suppose that won't hurt none. Think maybe he paid about $75 for them. Al stock sells for around $3.50 to $4.00 a pound at the yard and suspect the sink weighs about 9-10 pounds each.
Regards,
Elvin
Anybody know if those Ceramic/Aluminum oxide insulators would match with a TO-264 packages (OnSemi MJL21193/4)? I compared the dimensions, and they're just a bit smaller (1-2mm), would that be OK or are the insulators too small?
As for the heatsinks, does anyone know a good place for big heatsinks?
If not, then I think I'm going to try 6x6" of those ebay anodized heatsinks per channel and see how much bias I can set before getting them too hot.
Thanks.
Paul
As for the heatsinks, does anyone know a good place for big heatsinks?
If not, then I think I'm going to try 6x6" of those ebay anodized heatsinks per channel and see how much bias I can set before getting them too hot.
Thanks.
Paul
Humm, I thought the 21193/94 were TO-247P package. I'm using these insulators with my 21193/94 devices and they wofk just fine. They are just slightly smaller but still cover the entore metal area of the device. These pics might help but its still a bit difficult to see exactly. These devices are Toshiba 2SC5200 and 2SA1943.
Mark
Mark
