Also, if people need more gain from the iBUFF you can increase the value of R6. But if you increase the value of R6, then you may need to run the circuit with a higher supply voltage for more headroom.
-Frank
-Frank
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An inexpensive audio transformer with DIY projects
- Thread starter boomertech
- Start date
Just so everyone knows... I will not be building these either (so I won't have a list
). I just wanted to design a transformer DI that would make for a nice DIY project.This iBUFF can isolate your pedal board from your amp and FOH mixer. From what I can remember, most onboard amp DI's are not 100% isolated... this one is and it has a transformer! A transformer!
-Frank
- Feb 16, 2008
- 21,240
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- John K Custom Basses
shouldn't it be a male XLR though?This XLR/TRS combo jack could be used for both output jacks in the iBUFF, so that it is even more versatile for connections:
-Frank
Maybe... but I was thinking about the bin of balanced cables that I had a few years ago. M/F M/M F/F... I had all of them to work with for any situation.
-Frank
- Feb 16, 2008
- 21,240
- 23,636
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- John K Custom Basses
okay, i have a PCB drawn up for it. i'll etch it tomorrow and build it up for testing.
Awesome John! If the level pots feel like the bulk of the adjustment is bunched up at one end of the rotation, then you may need to use linear taper.
I was thinking about the output XLR jack... if people used the "standard" male connection on the pedal and carried a XLR to TRS adapter and a TRS to XLR adapter, then most likely connection scenarios would be covered.
-Frank
- Feb 16, 2008
- 21,240
- 23,636
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- John K Custom Basses
I was just calculating the output levels for the XLR with a connection to a 600ohm input load that some equipment might provide. With a 600ohm load the XLR output (level pot maxed) is near unity with the input level. If you want the XLR to have more than unity levels, you will need to increase the R6 value.
If you plug into a Mackie mixer with its 2.55K XLR load, then the iBUFF XLR output should have approx +3dB max level with R6 at 22K.
-Frank
If you plug into a Mackie mixer with its 2.55K XLR load, then the iBUFF XLR output should have approx +3dB max level with R6 at 22K.
-Frank
- Feb 16, 2008
- 21,240
- 23,636
- Disclosures
- John K Custom Basses
- Feb 16, 2008
- 21,240
- 23,636
- Disclosures
- John K Custom Basses
With R6 at 47K, the XLR with a 600ohm load will have approx +7.6dB max output. The TRS output with a load of 10K or greater will have approx +10.5dB max output.
-Frank
Edit: When I was calculating the max output levels for the XLR and TRS, I used the configuration where both secondary coils are connected in series (like the Transboost circuit) with a gain modifier on the primary side. So all of my output calculations will be lower, because I did not factor in the change in source impedance for the single coil.
-Frank
Edit: When I was calculating the max output levels for the XLR and TRS, I used the configuration where both secondary coils are connected in series (like the Transboost circuit) with a gain modifier on the primary side. So all of my output calculations will be lower, because I did not factor in the change in source impedance for the single coil.
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Hey guys I was just directed to this thread because I had started:-
Link Removed
( also posted something similar on diyaudio.com forum and they shouted me down.) I understand that you're not building pedals, but are you selling boards? Or possibly gerber?
Link Removed
( also posted something similar on diyaudio.com forum and they shouted me down.) I understand that you're not building pedals, but are you selling boards? Or possibly gerber?
There were no circuit changes that required a different PCB layout. Only the values of a few resistors were changed and the opamps.
-Frank
- Feb 16, 2008
- 21,240
- 23,636
- Disclosures
- John K Custom Basses
the PCBs have always been the same. it's just a couple of different component values.
after a couple more, i'm not going to be making any more of them for sale.
