B1 Buffer Preamp

[Nelson Pass]

We are writing the year 2008 and these are the manufacturing tolerances of state-of-the-art producers!?

You'll miss them when remaining stocks are gone.

😎

 

[Skorpio]

Kiwame. The pot closes the circuit to ground. [/QUOT

Yes it does, as long as the wiper is in contact with the carbon track


🙂

 

[Tolu]

You'll miss them when remaining stocks are gone.

😎

Then I will hoard them and in 20 years I will sell them as NOS parts to ensure my retainment pay! 😀

 

[Salas]

Kiwame. The pot closes the circuit to ground. [/QUOT

Yes it does, as long as the wiper is in contact with the carbon track


🙂

We can patch everything up just in case, or we can throw as many components out as we can. If a pot becomes dodgy, noises will not be absorbed as with having a failsafe Rg. In a DIY case there is no face to lose, we replace the pot. I am aware of what Rg is for in B1. I can make final decisions after all else works as wishful thinking likes them to work. First thing is not to get offset in practice. If it will appear in a bad way, some capacitors will appear on the perfboard, and then the parts count and their quality will be overshadowed. I can patch it up as much as that Marv guy's face in Sin City then.

 

[moe29]

 

[Salas]

Yup, thats the dude.

 

[avo7007]

Anybody knows if the B1 preamp has enough juice to be a good headphone amp too?

 

[stefanobilliani]

Anybody knows if the B1 preamp has enough juice to be a good headphone amp too?

Of course not with 32 ohm HP

 

[A Sanchez]

B1 and should be in business .....to drive my drive my ChipAmp and F5 soon 🙂
Loved the new chipamp I built so I am sure to fall over when I hear the F5 🙂

Hi Udailey,

Have you finished your B1 and tried it with the chipamp? Your veredict?

Antonio

 

[udailey]

I got involved in another project at home and have been working on that. My biggest issue is the enclosure. I dont know what I want it to look like yet. So, no B1 yet.
Uriah

 

[Nelson Pass]

Then I will hoard them and in 20 years I will sell them as NOS parts to ensure my retainment pay! 😀

That's my plan, go find your own.

😎

 

[BURNER]

Hi Choky

Sorry for stealing your idea

I modified B1 power supply (BZLS style; positive side, IRFP240 instead of IRF610), replacing zener stack with 12 x small-green-LED stack.

The output is nicely stabilized at +19.4V

About the sound ...
Running LED-powered B1 with F5, it's huge improvement 😱
* Mid seems to be warmer & sweeter
* High is more relaxed and silky
* Cleaner bass

Listen to a track 3 "High Life" of CD: Jazz at the Pawn Shop Vol.1 is a spooky experience as every instruments got better shape and focus !

Thanks for sharing your experiences

🙂

 

[Zen Mod]

Hi Choky

Sorry for stealing your idea.............
🙂

yup ; I certainly invented that

when you have time - try B1 with split supply ( +/- 9V ) ;

you'll get rid of input cap , and even better supply rejection

 

[Skorpio]

How critical is B1 layout corcerning stability?

Specially input and output wires....could the be close without problems?

 

[Zen Mod]

How critical is B1 layout corcerning stability?

Specially input and output wires....could the be close without problems?

no more than any other low gain stage ;

so - keep those wires as much apart you can 😉

 

[Tolu]

Re: Basically what I have done by now

Found some spare time, and populated the perf-board. Done half the point to point also. I am putting together 1 positive & 1 negative regulated PSU, 1 output delay relay circuit and 2 channels of capacitor-less B1s. Hopefully in the next few days I will find time to finish it and test it little by little. Will report.
Next post includes the awfully sketched schematic.

Hi Salas

any listening experience yet?

 

[Salas]

Had work to do and I left this little project behind. I will have to finish the point to point soldering and put it in a small plastic box along with a pot and connect it up so to see about offset behavior and square waves so to adjust resistors and PSU trimmers if needed. Then I will listen. If spare time is found, I will be ready to report everything in a couple of days.

 

[stigaard123]

I saw with some interest, that a solution for a active crossover was possible with this simple and hopefully good sounding buffer. For a start I would like to make a active low pass crossover with 12db at 150 Hz.

I just added another B1 and placed R7 + R8 and C4 + C5 between the two B1's.

Is that all? Or are there more into it?

It is 6.8 db down at 150 Hz compared to the -20dB input, so it looks promising.

 

[Skorpio]

I saw with some interest, that a solution for a active crossover was possible with this simple and hopefully good sounding buffer. For a start I would like to make a active low pass crossover with 12db at 150 Hz.

I just added another B1 and placed R7 + R8 and C4 + C5 between the two B1's.

Is that all? Or are there more into it?

It is 6.8 db down at 150 Hz compared to the -20dB input, so it looks promising.

I think your C4 should be connected to output instead of ground to get it right...

 

[Zen Mod]

deja vu ?

I saw with some interest..........

http://www.diyaudio.com/forums/showthread.php?postid=1555159#post1555159