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Another B4 Thread

Thanks Mudlark. Going to check it over again tonight. I am going to swap out the J501/505's. I managed to get some 1N5287/1N5297 CCd's, so they will go in tonight.

Keith
 
Checked the Board over tonight, the voltage's are all over the place. So it was out with the iron, and after a bit of a fiddle about i managed to get the J501/505 CCd's out. I wasn't sure about putting them in originally , due to a few reported problems with them.
In went the 1N5287/1N5297 ( semitec equiv ).
Voltages are a lot nearer to Pd's spec now ( if i am measuring right ) . I will wire it back up in the morning and report back.

Keith
 
SORTED!!!. It was the J501/505 from tubeshunter that was the problem. Now replaced with 1N5287/1N5297 CCD's. Wired up all the inputs/outputs this morning. i decided to use my daughters old Eltax speakers just to try out. They are a bit tatty, with tweeters pushed in by the kids, and one bass cone pushed in also.
Initial impression is a very open and natural sound, using Ansar Supersound Caps on the input and output. The build is very close to the Original BOM, just got a cheap 10K pot in at the moment from maplins. Going to give it time to burn in and then slot it in to my system see how it sounds.
Its only mounted on a bit of ply at the moment, with a couple of aluminium end plates for the sockets/pot.
Bass may be a bit light at the moment, but i put this down to the speakers.
Thanks for all the help guys.

Regards Keith
 
If you followed the stock BOM the lightness in the bass may be a result of the cutoff freq/time constant being wrong.. Standard BOM is -3db at 35hz or so (so well in the audible range)..

Do check your input cap/resistor values to make sure this isnt an issue. I posted links to an online calculator a while ago.

And it does take time to settle.. Sounds sublime (IMHO obviously) once settled.

Sam
 
Thanks Sam. just put the B4 into my main system. its got plenty of bass and not lacking at all. I used 2.2uf with a 22K input resistor. I am very impressed and it can only get better with a good burn in. Got loads of volume too using a 10K pot.
This build is for a friend too, he will be pleased. Going to order up some Hi-Fi 2000 case's now, to house them.
Now on with building my own board up. Should i try the big teflon coke can caps for this one ? . time for the soldering iron.

Keith
 
I loved the sound of the big teflons... Get some test pins and install them on the positions where you will want to experiment with caps/resistors... Makes life so much easier when it comes to tinkering.
I also used them on the 6 pins for the pot as I may swap that out again (currently on a cheap stepped attenuator).

My next build I will be doing all the mods suggested on here, including C0G's and playing around with the supply stage.

Sam
 
It's had 30hours burn in now!. The sound is very detailed , separation of instruments is superb especially when the tracks get complex. Voices are natural and overall it has a good grip of the music. Not quite got the slam of my NJ motherboard, but it portrays music different to what i am use to.
I will pass it over to my mate today because that's who i built i for. See what he thinks of it. Must remember that at the moment it is only powered by a nondescript power supply, and has got a £1 maplins Volume pot in. So when he decides what he want's in the finished build, it can only get better.
It has given me a lot to think about for my own build. I will be trying out some of the other options mentioned in other threads probably .

Keith
 
kropo said:
Is there any place where I can purchase the necessary PCBs? And is BOM somewhere?
Click to expand...
337alant said:
PCBs maybe? http://www.pinkfishmedia.net/forum/showpost.php?p=1612597&postcount=222

Alan
Click to expand...
That link refers to the diodes only - I am the only original source of the boards but it'll take another group by to supply in any quantity. I did post an interest check a couple of weeks ago and got no postings or responses. If it remains like that there will be no more.

Neil
 
Neil,

Out of interest, roughly how many boards have been sold in total across the various group buys?

PD
 
Well my mate has just spent most of today auditioning the B4. He told me that he could not believe the improvement that it has brought. He is using a Linn cdp/speakers and feeding the B4 into his Linn amp. So thats one happy chappy then.

Keith
 
Almost 2 weeks gone by now, and my mate cannot praise the B4 highly enough. He is still using it rigged up on the test bed that i threw together. Just keeps on saying that it ticks all the boxes , and when am i going over to have a listen.
In reply, i say " give it me back, so that i can put it in a case, and fit a good volume pot and better power supply " . But he likes it that much i may have to send the boy's round to lever it away.

Regards Keith.

P.s This is a seriously good bit of Kit. Thanks PD and Neil.
 
337alant said:
Keith,
Get the 15-0-15V, after smothing and regulation you get a nice 15-0-15v with good headroom.
http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=160654750172 , this is expensive buy works very nice and comes with a PCB to mount it on its very quiet and has very low radiated field

Alan
RS or Farnel may sell something similar
Click to expand...
I have one of those transformers left over from a project a couple of years ago which I'll dig out for my B4. That PCB mounting board is a tidy/aesthetically pleasing solution, but I see it is shipped as part of the transformer purchase from eBay. I'll drop the seller a note, but has anyone seen a similar mounting board for these transformers available to buy separately?

If anyone is thinking of buying this transformer, check out RS first. Their identical Nuvotem item is half the price.

Thanks,

Duncan
 
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sam_cat said:
This any use:

http://www.amb.org/audio/sigma24/
Click to expand...
Thanks Sam, but not quite the right pin spacing. Also it's setup for one output only. The PDF on the eBay listing shows that his transformer is exactly the same size/shape/pin spacing as the RS/Nuvotem item. Same factory, different badging? Hence his board, if I can get hold of it or one like it, will be a perfect fit.

I could bodge one up from Vero board, but I like things to look neat on the inside too!
 
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