Tube DI Box

[ruffrecords]

I have nearly finished the PCB. I decided to not include the White follower since it has no gain and it is the only one that needs bias resistors (I have modified Merlin's cathodyne to be self biasing). I am creating a spreadsheet that shows the components values and links for the various options (SRPP, mu Follower, cathodyne and cathode follower [the latter two preceded by a CC stage]). The board is two inches by four inches which unfortunately is too tall to fit in a 1U enclosure (should you wish to do so) so I am toying with the idea of changing it 40mm (~1.5 inches) tall so it will fit in a 1U enclosure. Also, all the tracks are on the top side of the PCB except the ground plane which is on the bottom. This means it may be possible to create a single sided version for the self etchers to use.

Cheers

Ian

 

[rock soderstrom]

Also, all the tracks are on the top side of the PCB except the ground plane which is on the bottom. This means it may be possible to create a single sided version for the self etchers to use.

As a self-etcher, I think that's very good! Depending on the components you intend to use, it might be better to switch sides so that the ground plane is at the top and the normal solder side at the bottom.

If it means too much work for you, don't do it. Your circuit design is much more important. We self-etchers can quickly build a PCB ourselves, the whole thing will probably remain quite manageably complex.

 

[Wavelength]

I finished and sent some files to Ian today on a powered version using the Hammond 261D6 power and any 10H or better choke or MEC50 from Tentlabs. Mine is SRPP only as I have done that a bunch of times. 2K output Z running about 5ma into a 10K load thinking Jensen 10K:600 since I have some at the office.
Probably get 5 to try out and see....
Here are my files.
G.

 

[MidnightArrakis]

>> I just stumbled across this D.I. image from a 1980 issue of "Studio Sound" and causing me to tumble down a flight of stairs!!! I am including this image here because it appears as though this unit has some interesting features:


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[Rob Flinn]

>> I just stumbled across this D.I. image from a 1980 issue of "Studio Sound" and causing me to tumble down a flight of stairs!!! I am including this image here because it appears as though this unit has some interesting features:

View attachment 128958
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I have 4 of these DI boxes & also the version which is 4 of these DI's in a 1U case with mains PSU. They were very popular at the time. They had other interesting features which you can't see in the photo. They had an option to phantom power with an extra pcb. They had 2 PP9 batteries but ran on just one/ The second battery took over when the first failed. All the electronics fit to the front panel & it screws into the plastic rear box. This DI was superceded by this one https://www.bax-shop.co.uk/di-boxes...GU_C85M1Lo5egQCCIHrpcfz4ixJQOXo8aAjaTEALw_wcB

 

[IBarfoot]

>> I just stumbled across this D.I. image from a 1980 issue of "Studio Sound" and causing me to tumble down a flight of stairs!!! I am including this image here because it appears as though this unit has some interesting features:

View attachment 128958
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The 116 was a great DI box, almost bomb proof, sounds pretty good too. Much better than the modern replacement in my opinion, the modern replacement always seems to die on me, luck of the draw I guess.

 

[Wavelength]

I think the idea here is just the guts of a DI. Adding the other features is pretty easy to do and can be added with a little work.
I sent these files off to JLPCB yesterday. Should have some back soon for testing. I am going to look for a simple enclosure to put this in. I plan on using a tube shield for the 6922 and will have a TS input and through with XLR output and ground lift, maybe inversion.

 

[ruffrecords]

In other news I just tested positive for Covid. I am in the chesty, can't get enough sleep stage right now. PCB is just about done but I am not going to commit it while I feel this crook.

Cheers

Ian

 

[rock soderstrom]

In other news I just tested positive for Covid. I am in the chesty, can't get enough sleep stage right now. PCB is just about done but I am not going to commit it while I feel this crook.

Cheers

Ian

Uhh, you seem to be having a streak of bad health at the moment. All the best and a speedy recovery - take it slowly!

 

[TwentyTrees]

Get well soon, Ian!

 

[IBarfoot]

Typical, hang in there may it pass quickly.

 

[MidnightArrakis]

In other news I just tested positive for Covid. I am in the chesty, can't get enough sleep stage right now. PCB is just about done but I am not going to commit it while I feel this crook.

Cheers

Ian

-- THIS -- is devastating news to learn, Ian!!! PLEASE be careful and do all that you can to fully recover and become well again!!! Similar to yourself.....at 75-years old, I am doing all that I possibly can to -- NOT -- become stricken with any of the COVID-viruses and/or their many variants!!! It's a new and dangerous world that we are all living in!!!

>> BEST WISHES ALWAYS!!! <<

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[ruffrecords]

Many thanks for all the good wishes. Right through the pandemic we were very careful and managed to avoid the virus even though all our kids and grandchildren got it. Just when you least expect it the damn thing gets you and being in your 70s and asthmatic does not help.

Cheers

Ian