Brother of Quasi

[Wasim]

Nice work Wasim,

You can use MJE15032 and MJE15033 without any problems and as OS suggests the MJ15003 will be perfect for the output stage as long as the DC rails never ever exceed 70 volts, so 65 volts might safer.

You will need to use a L-shaped heatsink bracket to mount the transistors on and this needs to be bolted firmly to a large heatsink. The bracket needs to be at lease 5mm thick though so you have enough thermal conduction to the main heatsink. Never operate or even set the amp up without the heatsink bracket bolted to the heatsink.

The bias and the output offset adjustments are the same as the Nmos series.

Cheers
Q

Hi Dear Quasi,

Thanks a lot you have answered all my questions?

Regards

 

[Wasim]

Hi Dear Quasi and all,

I have constructed the two Modules of N-bip300. I got a very strange problem when I turn them on. The one module is (through 100ohm 5w resistor) giving 0.3VDC. And the other module is (through 100ohm 5w resistor) giving 53VDC and I turn it off. I have checked everything and everything seems to be ok Can you help me with this?
Can I check TO3 mosfets with multimeter? I used the same supply that I am using with Nmos 350 (40 0 40 transformer).

Regards

 

[AndrewT]

I have constructed the two Modules of N-bip300. I got a very strange problem when I turn them on.

did the light bulb stay lit or flash and go dim?

 

[Idefixes]

Due the difficulty to mount a TO92 tigly on main dissipator, could T8 (BC546) replaced by a another bipolar in TO126 or T0220 package?

Marc

 

[AndrewT]

many of the To126 packaged transistors would make an excellent Vbe multiplier.
One can also glue a To92 or Eline to the face of the heatsink or glue a SOT23 to the collector lead of the output transistor.
Lots of options. But importantly the thermal resistance between the monitoring transistor and the hot face must be low. i.e. no air in the gap and the gap to be very low.

 

[Idefixes]

But importantly the thermal resistance between the monitoring transistor and the hot face must be low. i.e. no air in the gap and the gap to be very low. [/B]

So a TO92 (BC546) glue or pressed on main heathink with thermal grease between could be a good solution as you wrote it. So i will reroute quasi work to adapt it for T0264 BJT.

Marc

 

[Idefixes]

So i will reroute quasi work to adapt it for T0264 BJT.

Marc

I was taking a close look at nmos project. I was look the schematic that has a few minor change compared to Nbip. I saw nmos pcb for To247 on quasi pages. Is it a silly Idea to use this pcb with few adaptation : replace base resistor by wire or 2R2 as there is in lynx project, et solder at bottom side un 100nf on T8????

Marc

 

[Idefixes]

One more question to quasi or ohters : You put 330µf between + or - rail and ground why putting 200V one...Quasi you have them got from hand and putting then on? Since the rail for my case will not exceed 50V, 330µ/63V will be sufficient or am i wrong?

Marc

 

[Idefixes]

I begin to collect together the possible part for BoQ i have on hand.

Most havy of parts are from industriel rubbish ( Caps, heatsinks, and the 2x (336va 1x24v) blue tranny). I have two 3 batch of 25 MJL1381A and 3 batch of MJL1302, 25 MJ15003, 25 MJ15004, 25 MJE15030, 25MJE15031, 25 BC556, 25 BC 546. Since Nbip is based on NPN i will clearly use MJ15003 or MJL3281. Any preference for one?

I will build one first version on AndrewT advise : 3 pair NPN output, i will first use the two yellow tranny above. They are 400va 2x18v (il will put secondary in serie to obtain 1x36Vac). If i find amp suit i will by a 500va 3x35Vac pour final buid. Next step could be building 5ch with 2 output pair pro channel for my futur HT/music room.

Marc

 

[quasi]

Hi Marc

That looks like an impressive bundle of parts. Did you say you got them out of rubbish? If so, nice haul.

I used 200v capacitors for the on board filtering because I get access to lots of old PC power supplies and strip the capacitors from these. You could use capacitors you have on hand provided their voltage rating is more than your supply voltage by at least 10% (maybe 20%).

A TO264 transistor may not have the desired characteristics (gain, thermal change). Try using a TO126 transistor that will still give a screw hole mount.

Cheers
Q

 

[quasi]

Hi Dear Quasi and all,

I have constructed the two Modules of N-bip300. I got a very strange problem when I turn them on. The one module is (through 100ohm 5w resistor) giving 0.3VDC. And the other module is (through 100ohm 5w resistor) giving 53VDC and I turn it off. I have checked everything and everything seems to be ok Can you help me with this?
Can I check TO3 mosfets with multimeter? I used the same supply that I am using with Nmos 350 (40 0 40 transformer).

Regards

Hi Wasim,

Did you sort your amp out? If not make contact or post again so we can sort it out together.

Cheers
Quasi

 

[Idefixes]

Hi Marc

That looks like an impressive bundle of parts. Did you say you got them out of rubbish? If so, nice haul.

I used 200v capacitors for the on board filtering because I get access to lots of old PC power supplies and strip the capacitors from these. You could use capacitors you have on hand provided their voltage rating is more than your supply voltage by at least 10% (maybe 20%).

A TO264 transistor may not have the desired characteristics (gain, thermal change). Try using a TO126 transistor that will still give a screw hole mount.

Cheers
Q

Hi quasi,

Yes most parts came out from industriel rubbish. These are only samples i selected from stock for BoQ. Quasi i don't understand this :

TO264 transistor may not have the desired characteristics (gain, thermal change). Try using a TO126 transistor that will still give a screw hole mount.

The To264 (MJL3281A) transistors I have may be used only in Output stage as power transistors. Are they not suited for this employement? If there are is they a significant difference in sound personnality compared to MJ15003 ones.
For driver I have MJE 15030/15031. For To92 i will use 2SC1845, BCC556, BC546.
I will use a voltage rail on about +/- 50VDC, so i don't need 4 output transistor pair. I redrawn your layout for my propre use. Since I have my own DC protection i deleted it from amp board.

Marc

 

[Idefixes]

So a TO92 (BC546) glue or pressed on main heathink with thermal grease between could be a good solution as you wrote it. So i will reroute quasi work to adapt it for T0264 BJT.

Marc

Hi Marc

A TO264 transistor may not have the desired characteristics (gain, thermal change). Try using a TO126 transistor that will still give a screw hole mount.

Cheers
Q

Ok i read back what I writtened, and i think i understand what you wanted to say. My writting wasn't clear. TO264 transistor wouldn't be used in BC546 place but in TO3 transistor place in output stage.

best regards Marc

 

[Idefixes]

Hi,

here is the adaptation of quasi layout to TO264 package for 3 pair of NPN. The board as been downsize 215x110mm.

The quasi layout spirit (grounding methode, VAS near input stage for exemple) as been keeping. Transistors will be mounting direct on heatsink. I will try to switch BC546 for thermal trakinkg by 2SC2911 for better heatsink mounting.

Marc

 

[Wasim]

Hi Quasi,

I am sorry. I visited this thread after long time I will make these amplifier again and then I will get your help. currently I am building your other amplifier (Acrk400) 🙂. Thanks for the reply.

Regards

 

[Idefixes]

I made some little evolutions on TO264 board to reduce the pcb size a little bit

In the same time i manage to root a lighter version with 2 bipolar pair. It's for HT use or for more sensitiv seaker.

On Nmos tread quasi give some tips to estimate the number of necess

 

[Idefixes]

I made some little evolutions on TO264 board to reduce the pcb size a little bit

In the same time i manage to root a lighter version with 2 bipolar pair. It's for HT use or for more sensitiv seaker.

On Nmos tread quasi give some tips to estimate the number of necessary transistor pair based on power there power dissipation rating. I supose i can use this tip for bipolar. I will a highest use 35VAC trafo. The most power i could expect is about 190W/4ohm. With one MJL3281 and 360W power dissipation at 30% handle 360x0,3=108w with 2pair and 216w it seems to be good enough for my requierments. Am I right? In the same order Quasi shown on his web site a table with resitor value adaptation function rail voltage. Since mosfet and bipolar version of quasi have same topology at these location could the first one modification applied to the second one?

Marc

 

[metal]

I am wondering what was the experience of people built both MOSFET and BiPolar versions? What differences did you notice, performce, etc..

 

[norazmi]

transistor replacement..

Hi all,

Can i replace trans mje15030/31 with FJPF1943/5200 to220F ( http://www.fairchildsemi.com/ds/FJ/FJPF1943.pdf ) ?

I`ve build nmos 200 and nmos350/500 (10 sets) and i`ve success build them all with no problem at all, i`m always do with lower volatage first time setup before power it with high voltage.

I`m going to build this system with 10 pair power trans to power up subwoofer 8 ohm 750 watts 18 inch, just wanna check few component might be upgrade for high current source such as mje340/350 and mje15030/31.

Actually i`m not build this thing for commercial and i`m just used it for myself at home, car and pajero, because sound system is my hobby and i love music.

Hope can get more info from expert users here for any suggestion. Exspecially quasi and other expert members.

Regards.

 

[bigpanda]

Hi Indefix,

I have seen you got a bundle of MJ15004 with you. Since you are using 15003 only for this, would the 004 be just lying around? If you might be interested to 'get rid of them', wonder how much you will ask for and they are directly from 'ON's ? My email :

tony_chan_cf@email.com

I have some new boards for the Quad303 and can use 2 x 15004. so I am trying to get some stock but my vendor sells them at 100. If you are keeping them, could you tell me where you get them (you get them by 25pcs/bundle , right?).

Tks