Hi Juan,
The 2 watt resistors I used are smaller high temperature types. They are quite a bit smaller than the standard range. Yours will work fine but you may have to mount them vertically and facing each other to get them to fit.
A 100uF 63v will work fine.
Seeya
Quasi
The 2 watt resistors I used are smaller high temperature types. They are quite a bit smaller than the standard range. Yours will work fine but you may have to mount them vertically and facing each other to get them to fit.
A 100uF 63v will work fine.
Seeya
Quasi
Re: Working On It...
You can use the 2N transistors but watch for the different pin-outs. In terms of noise, I have never used them so I cant offer any advice except there is no way they would be as good as the 2SC1845's. I am counting how many 2SC1845's I have left and in a few days I will put some up for sale in the trading post. They are not cheap though, the last lot I bought were nearly $1 AUS each. But I decided it was worth spending 2 extra dollars per module.
Cheers
Q
hernanstafe said:
You can use the 2N transistors but watch for the different pin-outs. In terms of noise, I have never used them so I cant offer any advice except there is no way they would be as good as the 2SC1845's. I am counting how many 2SC1845's I have left and in a few days I will put some up for sale in the trading post. They are not cheap though, the last lot I bought were nearly $1 AUS each. But I decided it was worth spending 2 extra dollars per module.
Cheers
Q
Got 'Em!
Mr Q, thanks for the info, i got to get the 2sc's here in a local store tho🙂 so i'm working on the amp again, hope to have it up and working soon!!
Oh, one Thing! I was planning to put computer coolers over the mosfets instead of a simple heatsink, but i want to know what you think of this since t8 has to be on the heatsink and all that issue.
Thanks again!!
Mr Q, thanks for the info, i got to get the 2sc's here in a local store tho🙂 so i'm working on the amp again, hope to have it up and working soon!!
Oh, one Thing! I was planning to put computer coolers over the mosfets instead of a simple heatsink, but i want to know what you think of this since t8 has to be on the heatsink and all that issue.
Thanks again!!
Hi,
if one of the fans goes slow or stops then you could be compensating for the wrong temperature.
I think using two fan cooled sinks forces you into adopting twin temperature switches that lock off the mains supply on overtemp.
if one of the fans goes slow or stops then you could be compensating for the wrong temperature.
I think using two fan cooled sinks forces you into adopting twin temperature switches that lock off the mains supply on overtemp.
Re: Got 'Em!
How much did you pay for the 2SC1845's ?
All the FETs must mount on one common heatsink or on one heatsink bracket which is then heatsinked. You can add fans if you wish but this must done in addition too not instead of.
Cheers
Q
hernanstafe said:
How much did you pay for the 2SC1845's ?
All the FETs must mount on one common heatsink or on one heatsink bracket which is then heatsinked. You can add fans if you wish but this must done in addition too not instead of.
Cheers
Q
Parts & stuff
I have had some requests about supplying a kit for this amp. If anyone is interested I could do a components only kit, i.e; without the PCB and heatsinks / heatsink brackets or power supplies. So the kit will include all the semiconductors, capacitors and resistors required plus connecting terminals and fuses.
This might also help people who had difficulty in finding all the components.
I figured on charging what the components would cost if you purchased them from the electronics store, and maybe a little bit for postage. Let me know how this idea sounds and if you are interested.
If enough people were interested I could get PCB's made somewhere and include them as well.
Anyway let me know what you think.
Cheers
Q
I have had some requests about supplying a kit for this amp. If anyone is interested I could do a components only kit, i.e; without the PCB and heatsinks / heatsink brackets or power supplies. So the kit will include all the semiconductors, capacitors and resistors required plus connecting terminals and fuses.
This might also help people who had difficulty in finding all the components.
I figured on charging what the components would cost if you purchased them from the electronics store, and maybe a little bit for postage. Let me know how this idea sounds and if you are interested.
If enough people were interested I could get PCB's made somewhere and include them as well.
Anyway let me know what you think.
Cheers
Q
i paid 0,25Ar$, which would be about 0,10us$, they're really really cheap, but i find it weird i thought they were more expensive!!
About the kit, that would be nice, the problem is shipping it internationally, because at least here, customs adds LOTS of taxes to it and it becomes too expensive.
PS: At the electronic store, they have a list with the components and their specs; 2sc1845 has an Hfe of 100 in their list, which sounds very weird to me cause the datasheet says it has 600. All the other specs are correct. Are there different 2sc1845 out there?! Maybe their list has the minimal Hfe, while 600 is the typical value...i'm just guessing
About the kit, that would be nice, the problem is shipping it internationally, because at least here, customs adds LOTS of taxes to it and it becomes too expensive.
PS: At the electronic store, they have a list with the components and their specs; 2sc1845 has an Hfe of 100 in their list, which sounds very weird to me cause the datasheet says it has 600. All the other specs are correct. Are there different 2sc1845 out there?! Maybe their list has the minimal Hfe, while 600 is the typical value...i'm just guessing
That sounds really cheap. The best price I found on the web so far is about $0.50 US. Also the gain of 100 sounds a bit odd too. Maybe the store don't know what they have and provided they are genuine parts you've got a great deal.
What have others found?
Cheers
Q
What have others found?
Cheers
Q
I'll call them now and ask them cause it sounds way weird to me too. The problem is i can't find another transistor with that hfe. 2n5551 doesn't have enough and someone told me is not a good replacement for the amp. I really don't know what else i can use; i can get darlington transistors but can i use one of those? Or is there any other high Hfe transistor? i couldn't find any
Ok i just called the store. They told me the 2sc1845 is a very VERY common transistor, and that there's no mistake, the one they have is the only one existing ( i haven't bought it yet). The guy who worked there seemed to know it because he told me the specs without a book or anything, and in their list the specs are all the same, 120V, 50mA, the hfe is the only different thing. There was a mistake in the price though, the price is about 0,40ar$, and i'm not surprised there are a lot of components which prices is 1us$=1ar$, specially those small things, so i guess it's right...i hope it is!! They don't have it in stock right now, they're getting them on monday, so i'll go and buy them then. Meanwhile i'm getting all the other stuff, i still have to buy the transistors, the relay and a couple of caps.
Just to compare prices, how much did you pay for the mosfets? Here they cost 10,5ar$ each, that is about 3,3us$.
Just to compare prices, how much did you pay for the mosfets? Here they cost 10,5ar$ each, that is about 3,3us$.
Hi all,
I'm building nmos200, I ordered the parts today, and I need some help.
For r5, r10, r8,r22, r20 I could get 0,4W resistors
For r3, r11, r18 I could get 0,25W resistors
For r16, r21, r17 I could get 0,25W resistors
I could get bc546B-s and bc546C-s, and bd139-10.
Will these work for 32V or 37V rails? Also some of the resistors are not melf but carbon type... 🙁 Should I go for metal film ones, or these are not critical?
Thanks in advance!
I'm building nmos200, I ordered the parts today, and I need some help.
For r5, r10, r8,r22, r20 I could get 0,4W resistors
For r3, r11, r18 I could get 0,25W resistors
For r16, r21, r17 I could get 0,25W resistors
I could get bc546B-s and bc546C-s, and bd139-10.
Will these work for 32V or 37V rails? Also some of the resistors are not melf but carbon type... 🙁 Should I go for metal film ones, or these are not critical?
Thanks in advance!
All your resistor choices are fine for these rails. Note though that 32 volts is a bit low for this amp. It will work but you'll only get about 42 watts into 8 ohms. 37 volt rails will give about 59 watts into 8.
Try to use metal films throughout the amp.
Your transistor choices are fine.
Cheers
Q
Try to use metal films throughout the amp.
Your transistor choices are fine.
Cheers
Q
I am very much interested in #4 kits. I have 4 diy quasi boards waiting.
Quasi, you are so amazing !
hernanstafe said:
The amp will still work well, but using metal films will provide better performance. Having said that most commercial amps (even some expensive ones) still use carbon resistors.
Cheers
Q
Mr. Quasi: thank you for your help! The wattages you caluclated are fine for me. I have a Rotel RA820BX4 at home that is rated 2x30W@8ohms, and it feels pretty powerful for my purposes.
i quasi thanks for the reply, i will post a pic of the progres soon
it not look as clean as yours but hopefuly will sounds like yours.
BTW have you notice that the "Vpos" and "Vneg" in the PCB is backward (i mean it should be mirror, right?) i almost isolated the PCB the wrong side, lucky me i saw a picture of the board.
Ok back to work,
sorry my poor english
it not look as clean as yours but hopefuly will sounds like yours.
BTW have you notice that the "Vpos" and "Vneg" in the PCB is backward (i mean it should be mirror, right?) i almost isolated the PCB the wrong side, lucky me i saw a picture of the board.
Ok back to work,
sorry my poor english
Juan Spektor said:
I'm sure you will get good results.
Thanks for pointing out the reversed printing. It's often easy to miss something simple when things are too familiar. I plan to revamp the Nmos350 and Nmos500 boards soon just to make them look a bit tidier so I might fix that at the same time.
Good luck with the rest of your project.
Cheers
Q
"..............reversed printing................"
This is great ! I made four boards and spent the last couple of days getting it done. This morning while trying to put in some parts I realised that the pattern was reversed !
I certainly will not be making the board again . So I thought for a while and then decided that I will use it as it is and invert the power transistors and all the other active devices !
Will put up pictures after it is done ! And I thought that only I make such mistakes !
This is great ! I made four boards and spent the last couple of days getting it done. This morning while trying to put in some parts I realised that the pattern was reversed !
I certainly will not be making the board again . So I thought for a while and then decided that I will use it as it is and invert the power transistors and all the other active devices !
Will put up pictures after it is done ! And I thought that only I make such mistakes !
![drilling[1].jpg](/community/data/attachments/71/71410-8591ba1ac25e1aaac3e851a2f40e8a2a.jpg?hash=hZG6GsJeGq)