Brother of Quasi

Status
Not open for further replies.
Jump to Latest
#201
Hi SoundsGreat

That is one nice PCB, well done.

If you liked the mosfet amp then I know you'll like this one, you might even like it more.

This amp can be matched up with pretty well anything in terms of input and output. The module is very stable and will drive into most speaker configurations. Note though it is not short circuit proof.

Provided the amp modules are powered by a quality robust power supply you will get an excellent result.

Cheers & happy building.
Q
 
#203
Thanks !!

Hi,

Thanks a lot for the comments 😀 !



Note though it is not short circuit proof.
Click to expand...

What do mean exactly ? the DC detect circuit will not act ??

Am going to use a 650Va (65-0-65) Toroid for 2 ch with 44,000mfd filters ( Heavy PG grade) ! would that be enough ??


Dudaindc, No I didn't make the PCB ! I wish I could've done that ! here we don't get raw materials properly ! the copper clad available is pathetic and there's no supply of ferric chloride ! ohh the list goes on !

So I decided to get it done by a small PCB making industry !! they are well known to me so manage to get 6 boards done !

Regards.
 
#206
what is the regulation of the transformer?
or measure the actual open circuit AC input and output voltages.
What is the highest tolerance supply voltage from your mains?

What is the highest output voltage from your transformer.

Now calculate the highest DC voltage from the rectifier, if the amplifier fuses blow or you temporarily disconnect an amplifier from the smoothing caps?
 
#207
Hi,

Thanks a lot for reply !

I will measure them and see !

Actually I recently got the boards so have not assembled the components yet ! once all the components are assembled and ready to go,I'll test it with a lesser voltage trans and then if everything is ok then try to use this one !!

So will post once the assembly is over !!

here's another set pics of the PCB (better quality)

P1040487.JPG


P1040488.JPG



Regards.
 
#209
quasi said:
. Without a load the AC voltage might be as high as 70v or more and this equates to rails of 99 volts (too close).
Click to expand...
But, it's much worse than that.
if the transformer is 230:65+65Vac, then what is the opencircuit voltage when the input is 245Vac? (+6.5%)

What is the maximum tolerance on your local mains supply?
In the UK it is 254Vac. (+6%)
 
#210
AndrewT said:
But, it's much worse than that.
if the transformer is 230:65+65Vac, then what is the opencircuit voltage when the input is 245Vac? (+6.5%)

What is the maximum tolerance on your local mains supply?
In the UK it is 254Vac. (+6%)
Click to expand...


Very true, similar mains variance issues exist here, particularly in rural areas where long distances are involved in power delivery.

Cheers
Q
 
#211
Hi quasi,
Since i read that the nbip will perfect work with MJ21194, i could imagine that the MJL3281A will alsow work perfectly. I' got about hundred on hand (4 series of 25pieces), MJE15030/31 too. I will be happy with bettween 100-150w @8ohm and the double @4ohms. With the number i have on hand i could achive a good matching between halves amp. have any recommandation for rail voltgae and tranny power rating for 2 channel. Have you any recommandation to preamp that will well match with nbip?

Marc
 
#212
6pair of 3281 running on +-57 to +-60Vdc will give at least 300W into 4r0 and be safe for severe reactance 4ohm speakers.
Use 800 to 1000VA for a two channel amp and if possible get it wound with four equal 40Vac secondaries.

Send the spare 76 unmatched transistors to me in return for this great advice!!!
 
#215
3pair should give about 200W into 4r0 and survive severe 4ohm speaker loading from a 35Vac transformer. You should get fairly good performance for two channels from 530VA.

35Vac should give 50 to 51Vdc depending on regulation. Even more variation due to mains voltage changes.
 
#216
AndrewT said:
3pair should give about 200W into 4r0 and survive severe 4ohm speaker loading from a 35Vac transformer. You should get fairly good performance for two channels from 530VA.

35Vac should give 50 to 51Vdc depending on regulation. Even more variation due to mains voltage changes.
Click to expand...

Tanks Andrew that's good news for me since the rooms i play music into are quit normal in size, and the speaker i want to drive are not ESL's one with sensitivity and inpedance as deep as earth center. The speakers project i planed is
this

Cheers Marc
 
#217
Hi All,

I just have finished the Quasi's Nmos350. The amp is working really fine and producing excellent sound. The design is very nice. Thanks Quasi!!
Now I want to build this Bipolar version. Can anybody tell me that will 2N3773 (TO3) work fine with this amp? Is there any Good replacements of MJE15030 MJE15031?

Regards
 
#218
Hi dear Quasi and all,

I have done some work on N-bip350, just have a look.

I just have two three questions.

Can I use MJE15032 and MJE15033?

And for the transistor I got MJ15003 is it fine?

Do I need heavy heat sink or just an L shape is fine (as shown on the quasi's website)?

And how can we adjust the bias current like we did in Nmos350 (any construction document Quasi)?

Regards
 

Attachments

  • n-bip350.jpg
    n-bip350.jpg
    73.7 KB · Views: 1,214
#219
Very nice, I KNOW you will like the sound of NBIP, especially
bass. I use 4-mJ15003's(140V) but if you run more than 60V,
you might want MJ15024 (250v)or equivalant.
For a heatsink , I am going to use 4-4$ socket A processor
heatsinks screwed to a 1-1/2 " l bracket 16$ ,much
more surface area...
attachment.php

Just turn horizontal, tap holes,all done...
Very good work..😎
OS
 
#220
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
 
Status
Not open for further replies.
Top Bottom