advertisement


Another B4 Thread

keithsnaim

keithsnaim

Gone Fishing
I am almost ready to stuff my B4 board. I have plenty of 10uf 35V tants in my bits box, will these be ok instead of the 25V.
Can i leave out the output caps too. It will be feeding my Nap110's. Thanks Keith
 
Thanks Neil. Reading through all the B4 threads makes you realise how many variations there are in the builds. What to put in and what to leave out seems endless. If i stuff the board to the BOM all will be well ?.
Is there a must do ?, and a must leave out that i should be aware of.
 
keithsnaim said:
If i stuff the board to the BOM all will be well ?.
Click to expand...

I am a complete noob so that's what I did, with some alteration for R5/105 (to 27k) and C5/105 (to 1uF) after reading threads here. No trimpots, no variation other than what I've described - exactly as per the BOM. I am using it with a NAP250 and it sounds absolutely fantastic.

I did have a few problems but that was down to me connecting up the +ve and -ve rails to the board the wrong way around so I blew a few transistors. No big deal and worked fine once I'd realised what I'd done and replaced them.

Cheers,
Steve
 
Mine is bog standard pretty much and sounds fine. I am in sunny Cumbria if you need any help or a trial of a completed amplifier. Mine runs a Naim140.
 
Thanks guy's. I did one of Neils Mini Motherboards last year. This is housed in a nac42 case, and sounds very good too. It now takes pride of place in my Bi-amped system.
So i am looking forward to this build, due to the great reviews the B4 has had. I am building two , one for myself and one for a mate.
Mike ! i live near Rotherham, so maybe a meet would be possible. Keith
 
Yes, I'd go for something bigger.

I've used these http://uk.mouser.com/Search/Product...JAvirtualkey66720000virtualkey667-ECW-F2225JA

Have a pair of these to try http://uk.mouser.com/Search/ProductDetail.aspx?R=935C1W2K-Fvirtualkey59850000virtualkey5984-100V2-F

both of which are a tight fit -the latter at least can be easily set back from the board, but have a look at my thread on the 'interesting hum' to see how the panasonics fir and how one needed to be slightly twisted to avoid the case.

I've used these for the outputs http://uk.mouser.com/Search/Product...JAvirtualkey66720000virtualkey667-ECW-F2685JA

The size is dependent on the input impedance of the B4 (input caps) and power amp (output caps). My B4 has input resistors at 24k giving a -3dB point at aobut 3Hz, well away from the audio band. The power amp has input impedance around 19.5k, again giving a very low -3dB point.

Happy to try and arrange a meet up sometime. I'm in North Yorkshire, near Harrogate and work in Leeds.

Mike
 
Thanks Mike. I have plenty to ponder now. What value at R15 are you using. Keith
Ok just noticed its only there to protect the front Led
 
Hi Keith

I think I just used 10k for R15, but it might be a bit higher. It's not critical, it just sets the current through the indicator led. Too low and the led will be very bright until it melts, too high and the led will be very dim.

I'd expect 10k to 50k to be OK really. I think PD suggested a range somewhere in his build notes.

Mike
 
kieth
If you already have the 10K stock resistor then that would be Ok as well with 2.2UF
22ms/7.58hz

Alan
 
You must log in or register to reply here.


advertisement


Back
Top