Sorry for the delay
Hi All,
Here is the final version of the "normal" output board suitable for the Krell-Clone 😉
Gerbers will be uploaded on the web in a short while....
I'll let you know 😉
Later today or tomorrow, I will publish an Output Board according to Pavel's (Upupa Epops).....
Hi All,
Here is the final version of the "normal" output board suitable for the Krell-Clone 😉
Gerbers will be uploaded on the web in a short while....
I'll let you know 😉
Later today or tomorrow, I will publish an Output Board according to Pavel's (Upupa Epops).....
Gerber files and manual for the 2A Output Board can now be downloaded here for free:
http://www.delta-audio.com/OB-2A.htm
http://www.delta-audio.com/OB-2A.htm
can anyone explain me why Jan specify Re (emitter resistor) as 6W??
When Re = 0,5 Ohm, and the quiest current is 1A, why such high power resistor?
When Re = 0,5 Ohm, and the quiest current is 1A, why such high power resistor?
To wim : If you can, give there lower wattage, but remember, that small ones have lower impulse current ( lower overload, which can be caused by shorting on output ). 😉
win
I always use 6W emitter resistors in all my amps 😉
You can choose ones with lower Wattage, but as Pavel write:
"If you can, give there lower wattage, but remember, that small ones have lower impulse current ( lower overload, which can be caused by shorting on output )" 😉
I always use 6W emitter resistors in all my amps 😉
You can choose ones with lower Wattage, but as Pavel write:
"If you can, give there lower wattage, but remember, that small ones have lower impulse current ( lower overload, which can be caused by shorting on output )" 😉
Thanks for answering. It's no problem to use 6W types, i only was wondering why and now i know.
I have the original Aleph-X circuit boards from "hi-fi Zen". I am looking to trade them for a set of the latest rev BrianGT LM3875 Gainclone boards so contact me if you have them and are interested in trading.
Questions about fuses, triacs & caps
Hi All,
I'm not sure I entirely agree with Jan about emitter resistors and output devices failing. These are basically fuses for each output transistor, everyone will be much happier if the resistor dies first. So bigger will almost never be better, big enough yes, but huge will only expose the more expensive transistors...correct me if I'm wrong here...
On a slightly different note: In the event of a dead short on the output, or other gross failure, you had better have fuses. The power supply and output stages we are considering for this amp are quite large, current wise, and fires in less than adequate wiring etc are a definite possibility. The adcom gfa565, (>900w/2r) used 12a on each rail and 12a primary side, despite 10 pairs of 424/554 transistors. We can easily predict the output currents into sane (ie >=1ohm) loads, so we should use good sense in our designs.
If anyone with experience has input here chime in...I plan on using a fuse to allow the transformer to deliver it's rated VA, but no more. So here in the US, for my 600va toroids, 4 or 5 amps primary side, slo-blo. I 'think' this will defend the rest of the amp adequately, but perhaps I should include rail fuses as well? I am less concerned at this stage with defending my speakers, more my house...
Also has anyone heard of or tried a triac on the primary side as a way of turning the amp on and off? It seems it could be a cool way of shutting the whole shooting match down in if necessary, presumably more reliable than a relay?
If anyone needs 'em, I have a lot of NOS 50v caps (10's x 68000u) and (100's x 4700u) I'm perfectly willing to trade if someone out there has transistors or other interesting components.
Stuart
Hi All,
I'm not sure I entirely agree with Jan about emitter resistors and output devices failing. These are basically fuses for each output transistor, everyone will be much happier if the resistor dies first. So bigger will almost never be better, big enough yes, but huge will only expose the more expensive transistors...correct me if I'm wrong here...
On a slightly different note: In the event of a dead short on the output, or other gross failure, you had better have fuses. The power supply and output stages we are considering for this amp are quite large, current wise, and fires in less than adequate wiring etc are a definite possibility. The adcom gfa565, (>900w/2r) used 12a on each rail and 12a primary side, despite 10 pairs of 424/554 transistors. We can easily predict the output currents into sane (ie >=1ohm) loads, so we should use good sense in our designs.
If anyone with experience has input here chime in...I plan on using a fuse to allow the transformer to deliver it's rated VA, but no more. So here in the US, for my 600va toroids, 4 or 5 amps primary side, slo-blo. I 'think' this will defend the rest of the amp adequately, but perhaps I should include rail fuses as well? I am less concerned at this stage with defending my speakers, more my house...
Also has anyone heard of or tried a triac on the primary side as a way of turning the amp on and off? It seems it could be a cool way of shutting the whole shooting match down in if necessary, presumably more reliable than a relay?
If anyone needs 'em, I have a lot of NOS 50v caps (10's x 68000u) and (100's x 4700u) I'm perfectly willing to trade if someone out there has transistors or other interesting components.
Stuart
Stuart:
I do agree with you here, but in the case that somehow the emittor resistors get to the point where they smoke/blow, something more serious has probably happend to the transistors (outputs) already and causing rail voltage across these...
I'm probably going to use 5w ones as these are easiest to get!
In regards to fusing, i'm running a fuse (fast blow) on the primary side of each toroid which is less than the value of the mains wiring, 10amp wiring on the primary side, even with an 800va toroid i should be ok with a 7.5amp fast blow... Just! I don't mind replacing a fuse once in a blue moon as i'd prefer the fuse to blow rather than the wiring, etc...
As for rail fuses i probably wouldn't do this unless i was soldering them directly to the rails as i'd want a 100% guaranteed connection... I AM however fusing all the outputs (between speaker posts and outputs) as i want to have 4 ohm loading min, so i can easily calculate the fuse requirements and if i was pushing it hard, i'd prefer the fuse to blow rather than the amp to go 🙂
I am not, however, using the protection circuitry for SOA as i am changing a few things in the amp anyway!
I am going overboard with all the wiring, i.e. i am using 10amp wiring where 4amp will do, i'm using high current wiring for the rails, etc, etc. The power supply supports the whole amp and i want something like a fuse to blow rather than the wiring to catch fire should something go wrong!
Aaron
P.S. I'd love some of those caps (in fact, i'd love 6 of them!!!) (the big 68,000uf!) are you interested in selling? I'm in australia and we simply can't get things like that here for a reasonable price 🙁 E-mail me if you are interested 🙂
I do agree with you here, but in the case that somehow the emittor resistors get to the point where they smoke/blow, something more serious has probably happend to the transistors (outputs) already and causing rail voltage across these...
I'm probably going to use 5w ones as these are easiest to get!
In regards to fusing, i'm running a fuse (fast blow) on the primary side of each toroid which is less than the value of the mains wiring, 10amp wiring on the primary side, even with an 800va toroid i should be ok with a 7.5amp fast blow... Just! I don't mind replacing a fuse once in a blue moon as i'd prefer the fuse to blow rather than the wiring, etc...
As for rail fuses i probably wouldn't do this unless i was soldering them directly to the rails as i'd want a 100% guaranteed connection... I AM however fusing all the outputs (between speaker posts and outputs) as i want to have 4 ohm loading min, so i can easily calculate the fuse requirements and if i was pushing it hard, i'd prefer the fuse to blow rather than the amp to go 🙂
I am not, however, using the protection circuitry for SOA as i am changing a few things in the amp anyway!
I am going overboard with all the wiring, i.e. i am using 10amp wiring where 4amp will do, i'm using high current wiring for the rails, etc, etc. The power supply supports the whole amp and i want something like a fuse to blow rather than the wiring to catch fire should something go wrong!
Aaron
P.S. I'd love some of those caps (in fact, i'd love 6 of them!!!) (the big 68,000uf!) are you interested in selling? I'm in australia and we simply can't get things like that here for a reasonable price 🙁 E-mail me if you are interested 🙂
This is just shortly as I'm on the road on a business trip, and will first be back tomorrow evening or so....
Use the emitter resistors you like........
😉
Troy has asked me to make a combined board containing the main pcb and two output boards....
I will look into it when I'm back home 😉
Use the emitter resistors you like........
😉 Troy has asked me to make a combined board containing the main pcb and two output boards....
I will look into it when I'm back home 😉
Combining the main PCB and the outputboard sounds good! I am interested in it.
For Elso and others about the earlyer discusion of fake components dfrom NEDIS: I confrontated NEDIS with the story, and they told me that you can see at the articelcodes of the components were it comes from. So "partname-SAN" means the part is original Sanyo. If the articelcode says "partname-MBR", it means that the part comes from various A or B brands.
Maybey nobody read me earlyer post, where i asked if the PSU from the site of Rod Elliot (capacitance multplier) can be used for the Krell-cone. Is there anyone who can tell the answer??
For Elso and others about the earlyer discusion of fake components dfrom NEDIS: I confrontated NEDIS with the story, and they told me that you can see at the articelcodes of the components were it comes from. So "partname-SAN" means the part is original Sanyo. If the articelcode says "partname-MBR", it means that the part comes from various A or B brands.
Maybey nobody read me earlyer post, where i asked if the PSU from the site of Rod Elliot (capacitance multplier) can be used for the Krell-cone. Is there anyone who can tell the answer??
Nedis
Wim,
Yes if it is coded MBR you don't know where it comes from. And first they delivered TDA1541AS1 then without warning they sended the much lower grade TDA1541R for the same price. No chance in sending back.
wim said:
Wim,
Yes if it is coded MBR you don't know where it comes from. And first they delivered TDA1541AS1 then without warning they sended the much lower grade TDA1541R for the same price. No chance in sending back.
I see Elso, so what i am going to do in the Future, i ask them before ordering what the full artikelcode is of the components i want to order. If it is ....-MBR, then i don't order it.
I realy want to order there, becouse they are not expensive.
I realy want to order there, becouse they are not expensive.
nice picture...
Elso, you are looking good...or at least whoever that is in your avatar...
Aaron (nutttr) your email is turned off in your profile...you need to drop me a line if you don't want to turn it on...
Perhaps you guys are right, I was just assuming transistors as big as we are using can survive the rail voltage to ground for a little while. If the fuses or emitter resistors pop fast enough the amp will survive, the speakers are a different story...I have a couple thousand 10w, 0r68 resistors, so I'm going to use those and I don't think they will be good fuses...
Stuart
Elso, you are looking good...or at least whoever that is in your avatar...
Aaron (nutttr) your email is turned off in your profile...you need to drop me a line if you don't want to turn it on...
Perhaps you guys are right, I was just assuming transistors as big as we are using can survive the rail voltage to ground for a little while. If the fuses or emitter resistors pop fast enough the amp will survive, the speakers are a different story...I have a couple thousand 10w, 0r68 resistors, so I'm going to use those and I don't think they will be good fuses...
Stuart
capacitance multiplier...
Hi Wim,
With properly chosen components the capacitance multiplier will work perfectly, but perhaps isn't really necessary...
The cap-mult has a voltage loss associated with it's operation, the voltage it needs across the pass transistor(s) and reference components etc. You will need to increase the voltage of your transformer etc by this amount and make sure you put the pass transistors on a big enough heatsink etc. For it to work right, the lowest voltage from the rectifier and smoothing caps needs to be higher than the amps normal operating voltage, so you end up needing a power supply maybe 10% bigger.
A simpler and more reliable solution might be to use inductors on the rails, making a CLC power supply. Air cored inductors are easy to make, relatively cheap and don't die under overload conditions...I have some 12gauge 1mh coils I plan on using...The aleph building guys are using them very successfully.
Stuart
Hi Wim,
With properly chosen components the capacitance multiplier will work perfectly, but perhaps isn't really necessary...
The cap-mult has a voltage loss associated with it's operation, the voltage it needs across the pass transistor(s) and reference components etc. You will need to increase the voltage of your transformer etc by this amount and make sure you put the pass transistors on a big enough heatsink etc. For it to work right, the lowest voltage from the rectifier and smoothing caps needs to be higher than the amps normal operating voltage, so you end up needing a power supply maybe 10% bigger.
A simpler and more reliable solution might be to use inductors on the rails, making a CLC power supply. Air cored inductors are easy to make, relatively cheap and don't die under overload conditions...I have some 12gauge 1mh coils I plan on using...The aleph building guys are using them very successfully.
Stuart