Bo Hansen DI layout

[JohnRoberts]

Delete my account …I’m sure an trying to

done...

JR

 

[Rowboat]

"And I would want one to WHOM EVER made this"

= as long as you get what you want, you don't care who violates intellectual property and design copyright.

 

[JohnRoberts]

= as long as you get what you want, you don't care who violates intellectual property and design copyright.

Beating a dead horse?

That member has already been banned as per his own request.

JR

 

[xploited]

I finished my bo DI! tested, and working great. I tried a new way (to me) for the faceplates.. used a pcb service and designed it like a pcb, with silkscreen for the lettering. It worked out pretty great! My most professional looking prject yet, and WAY WAY WAY cheaper then frontpanelexpress or the likes.

Thanks for the kick ass project!

 

[klem]

What transistor parameters are important, especially for stereo matching / 2 channel builds?

Of course, my goal, as far as the transistor parameters can confer, is low noise, good headroom, and very similar output levels. I’ve searched the thread and Bo’s site with various terms, but found limited info on specific ranges / values to realize the above. I also still have much to learn about the parameters of transistors and the implications of the values so maybe I either overlooked something previously posted, or maybe the parameters are not that important for this circuit? I have a Peak Atlas DCA75 and can measure the following values:

hFE
Vbe
VceSat
IcLeak
Vgs(off)
Vgs(on)
gfs
Idss
Rds(on)

Of what I've found on the topic:

Above all, of course, I see repeated emphasis on using a known quality brand from an approved distributor to avoid the knockoffs. That's a given for me.

hFE: I see Bo states hFE should be “at least medium hFE” earlier in thread, I think also said it wasn’t critical but above 200 as minimum.

As an aside, if there's a good overview on the above values geared at a 101/102 level, I welcome the recommendation. I also have a project I'm trying to get these ready for in close to a week, so can't go too deep before making a choice in which ones I solder in...

Thanks in advance,

 

[Whoops]

What transistor parameters are important, especially for stereo matching / 2 channel builds?

As for transistors specifically, I think there's not much you can do besides matching them for HFE measured at the same current the transistors will draw in the circuit.

But if you want to match 2 units then the transistors might not be your first reason for concern,
capacitors can have more than +/- 20% tolerance, so you would need to match capacitors first.

And then how about the transformers?
Transformers will always have a +/- tolerance also, and I really don't see how could someone match transformers without buying a lot of them to measure and select, which would be quite expensive for just a simple DI box build

 

[klem]

What transistor parameters are important

Thanks in advance,

 

[Frdfrode]

Hi,

i've made one too with a Beyerdynamic transformer (5:1). It sounds great. I'm very happy of it!

But, i had an issue when i used it before a Fuzz Face (or a Tonebender). The sound at the output became fizzy. It's because the fuzz overload the source.
I solved the problem by placing an external buffer before the DI, and a "pickup simulator" after the "Through" of the DI.

Hi, I have some beyer dynamic transformer I maybe could use for this project. What are the specs on the one you used?