Speaking for myself
the main benefit of balanced wiring is less interference and enabling longer distances.
The need for a buffer depends on the power amp, some "plug and play" modules like Hypex and Purifi (Icepower?) may not come with any buffering built in,
the OEMs building complete systems using them design and build the buffer circuits inhouse
while these are great for DIYers doing the same.
The SE vs balanced capabilities offer a lot of flexibility choosing source and target hardware.
the main benefit of balanced wiring is less interference and enabling longer distances.
The need for a buffer depends on the power amp, some "plug and play" modules like Hypex and Purifi (Icepower?) may not come with any buffering built in,
the OEMs building complete systems using them design and build the buffer circuits inhouse
while these are great for DIYers doing the same.
The SE vs balanced capabilities offer a lot of flexibility choosing source and target hardware.
Jimk04,
John61ct is correct. For your application you need the BTSB since the TPA3255 is a balanced input amp (at least my version) and if you want to drive it properly, you need the SE to Bal feature since DCG3 is SE output. The gain of the TPA3255 with PFFB is only 15dB. So if the DCG3 can give you 14dB gain then set BTSB up as 0dB. But 6dB is useful to make sure you have max dynamic reach.
John61ct is correct. For your application you need the BTSB since the TPA3255 is a balanced input amp (at least my version) and if you want to drive it properly, you need the SE to Bal feature since DCG3 is SE output. The gain of the TPA3255 with PFFB is only 15dB. So if the DCG3 can give you 14dB gain then set BTSB up as 0dB. But 6dB is useful to make sure you have max dynamic reach.
The other advantage of using the BTSB Buffer is it has variable gain ! The output of many sources can be quite low. Most TPA3255 Amplifier modules (and other professional amplifiers) need at least 2 volts at the input and possibly more if using feedback !
Some TPA3255 amplifiers also need a balanced input although most offer the option of SE or Balanced by moving some jumpers. I also have some amplifiers that are SE only and this allows the amplifier to be used with a balanced source.
Here is the schematic and BOM for the new 90deg BTSB Panel Mount v1.2p board.
BOM is a zipped Excel file.
Attachments
Could it be used it to be used or adapted to boost audio signal that’s at speaker level?
ie with its inputs connected to the speaker-outs on an amplifier
I’m guessing not. But if it did it seems IDEAL to boost the output of a very high quality - but very low output - 45 DHT tube amplifier - just 2 watts
might there be a way to make this work with a different choice of components?
ie with its inputs connected to the speaker-outs on an amplifier
I’m guessing not. But if it did it seems IDEAL to boost the output of a very high quality - but very low output - 45 DHT tube amplifier - just 2 watts
might there be a way to make this work with a different choice of components?
You can pair the BTSB with a more powerful 0dB gain amp like a TPA6120 headphone amp chip and drive 32ohm loads to a couple watts. You can parallel 4 of the TPA6120 for driving 8ohm loads. You can also use an amp like the MOFO which is Class A and with +/-15v you can technically drive up to 14w into 8ohms.
I knew it wasn’t designed to drive speakers.
It was also described as “an indispensable part of your electronics toolbox” …
I see it fundamentally as a gain stage., with devices that boost signal. I was hoping it might be possible to use it a different way.
Apparently not
I’ve had several people PM me asking if the BTSB can drive the Purifi 1ET400A amp. Yes, of course, the BTSB can be used to drive any amp requiring a low distortion balanced input.
I have used it to drive an IcePower 1200AS2 and it works great. The selectable input gain is really useful to help match your system to the amp’s gain.
I have used it to drive an IcePower 1200AS2 and it works great. The selectable input gain is really useful to help match your system to the amp’s gain.
XRK - just a quick question on this calculation. Reading literally this equation I may use your buffer as a attenuator (by setting R19 higher than R29). But is this a safe in terms of stability and other performance parameters?
I am looking for -9, -6, -3, 0, +3, +6, +6 dB buffer/attenuator/gain stage with BAL/SE/BAL functionality and wondering if such idea is actually a proper one.
Regards,
One of the folks asked if it is feasible to adapt the design from 4 switchable gains to 7. It is if you now use a 6 position dip switch for each positive and negative half into the differential amp and size the input resistor corresponding to all the switches open to the -9dB choice and calculate the remaining ones in parallel with that first resistor to get to the remaining gain choices. As an example, using the feedback resistor of 4K99 an input resistor of about 14K1 results in a gain of about -9dB. If you just want to use the design as it is with different resistor values paralleling the 4K99 input resistance you will onyl realize 4 or 5 practical choices of gain and not the nice spacing you are asking for.