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Universal Buffer achieving -140 dBc (0.00001 %) THD

Hi Tom,
Any hockey yet?
Would you check my "wiring" diagram for a luxury UB set up please---balanced in to SE volume control to 2 x balanced out UB?
stay safe
tim
 

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Any hockey yet?

Sadly, no. I just received word that it won't start up until Aug. 31st at the earliest. Each day without hockey I die a little on the inside. I haven't found anything that can replace the camaraderie and stress relief I get from hockey. I should dust off my bike and go ride for a bit. See if that works...

Would you check my "wiring" diagram for a luxury UB set up please---balanced in to SE volume control to 2 x balanced out UB?
stay safe

The wiring is correct. Do note that you have the 4-pin outputs of the UBs flipped upside down, though. Pin 1 is to the left when you look into the connectors from the wire side.

Can the UB be powered up without line in/out connected? Only the +15v -15v and ground

Yep.

Tom
 
Do note that you have the 4-pin outputs of the UBs flipped upside down, though. Pin 1 is to the left when you look into the connectors from the wire side.

Ah......silly mistake I'm sorry Tom.
Not paying sufficient attention.
I've scribbled a version 2 diagram.
Am I right this time?

Many thanks
t
 

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I can watch all the hockey I want. That's not the issue. Playing hockey is what I need.

Yeah, I miss swimming big time. Pools are going to reopen here in a few days just as winter rolls in and I will be straight in following that black line every morning at least until it is all shut down again.


On another point Tom, and not to push you if you have decided to set it aside completely, but just wondering if you ever managed to do the buffer measurements for single ended and a some gain? I'm still sitting on my hands here wondering if your buffer is better than the ones I already have here.
 
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I just ordered 5 UB's for my preamp project.

Thank you for your order. I really appreciate it. I dropped it off with UPS this afternoon.

For power supply i was looking at the recom small smps @ 20w as mentioned earlier in this thread. Tom, if i recall correctly you said something about adding filtering to the output? Perhaps you can share your ideas on this?

I find a CLC filter works quite well. I optimized the cutoff frequency to provide good ripple attenuation while also not degrading the output impedance of the supply within the audio band. I optimized the filter for minimal peaking by careful component selection.
I'm planning to have a supply that's built like that (and that also adds a few other nice features) ready towards the middle of summer. The design is mostly done, but the lead time with RECOM is substantial.
I'm aiming for the supply to be a fully assembled module as it contains quite a few SMD parts.

I too wonder if the local ice rinks will open in the Fall. It's youth hockey that pays the bills. Speedskating is only 3 hours per week. But I think that the kids parents will be reluctant to have them playing hockey.

Yeah... At one of my last games before the shutdown, one of the guys showed up even though his wife had tested positive for COVID-19 and was in self-quarantine. It took me quite a while to pick my jaw back up from the floor after hearing that...

Tom
 
This is a very interesting buffer. Would it be possible to use it with a 50k pot in the following setup? DAC-POT-UNIBUF-AMP unbalanced.

I’m also looking at the “B1 mesmerize 10 year after” and there is a resistor value that needs to be changed from 200k to 500k to use the 50k pot. Would something similar be required with the uni-buf?
 
Get a MTB and hit some technical terrain. That will get your heart rate to squash territory... and then some.

TCD

The top pro squash players often wear heart rate monitors when playing in the major tournaments. During rallies ( which is of course most of the time in Squash as play is continuous) their heart rates are typically around the 190 BPM mark and often higher - I’ve seen some players hit 200. Bear in mind these are some of the fittest people on the planet with exceptional VO2 Max ratings, so imagine how hard they are working.

I’m a keen squash player myself, albeit nothing like pro standard. I’m 66 years old and my resting heart rate is 50. Whilst I’m on the subject, it’s an absolute travesty that Squash is not in the Olympics.
 
The top pro squash players often wear heart rate monitors when playing in the major tournaments. During rallies ( which is of course most of the time in Squash as play is continuous) their heart rates are typically around the 190 BPM mark and often higher - I’ve seen some players hit 200. Bear in mind these are some of the fittest people on the planet with exceptional VO2 Max ratings, so imagine how hard they are working.

Yes, I saw this and having played squash in my younger years am not at all surprised. If you compare elite squash versus XC MTB, the MTB heart rates
are slightly higher and sustained for unbelievable periods with virtually no break. Reflects my own experience, first XC race I entered, tore off the
HRM.... :eek:

I’m a keen squash player myself, albeit nothing like pro standard. I’m 66 years old and my resting heart rate is 50. Whilst I’m on the subject, it’s an absolute travesty that Squash is not in the Olympics.

Yes, have never thought about that but you are absolutely right.

WRT HR's, when I raced MTB's in my 40's, resting HR was sometimes just
below 40. Oesophageal Cancer, Chemo / Rad and 'Ivor Lewis' surgery put an
end to racing but still enjoy social riding for fun and fitness.

PS apologies for slight thread diversion.

TCD
 
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It can. Just connect the relevant pins on the jumper to a switch. Switch open -> Differential. Switch closed -> SE.

However, if you enable the single ended input mode with a differential source connected and powered up, the source might deliver poor performance (high distortion, possibly clipping) until you flip the switch to differential.

Tom