Need advise: Home "lab" test gear recommendation for amp & preamp testing (building and modifying by my own and for personal use )

[ADanalog]

Hi
Some background on myself: I am working on high speed mixed signal, lab's been part of my work life (the fun part is that I dont have to pay for the uber prices chaged for the equipment I am using LOL )

Now, turning back to my old hobby, and I enjoy playing around and building / modifying amps & preamps, and want to setup a home lab for that.

I will greatly appreciate advise to reduce my "failure rate" when choosing reasonably priced home level test equipment setup, where I am targeting ~$1000 for it .

Target testing:
Test Preamp, Amp , Cables (where I want to see if I can tune a cable to eliminate the D-type switching noise injected on it).
I am playing with both tube design and solid state .

I was thinking on :
QuantAsylum - QA403 : Aim for testing based SNR/ Linearity / Power-vs-Distortion / General SA / I would love if it had a trigger and could behave like a scope too, I just dont think it has a good trigger module ==> Is there a known similar cost alternative (not lower performance)

VNA: I was thinking of getting a simple NanoVNA-H4, this has a S12 capabilities of 70db. Looks like cost is a no brainer , and it can give the coverage for testing cables to the ultra sonic region (now the only problem I have is that this is a 50ohm driver ... so I am gong to have some fun, ideas ?

Home oscilloscope: For audio I was eyeing a higher bit depth ADC (14bit?), but I am not sure it is useful if I already have something like the QA403, but heck, I am so used to working with Oscilloscopes, thought of getting the simple but silly nice DPO350p

Thanks !

 

[DVDdoug]

Home oscilloscope: For audio I was eyeing a higher bit depth ADC (14bit?)

If the scope has "features" like FFT/spectrum analysis, etc., that may be useful. But for the visual display it shouldn't be necessary. For example, analog video has 480 or 525 lines of vertical resolution, which is about 9 bits.

 

[ADanalog]

Hi Floyd

I get it, I was thinking about it the wrong way, I get he SA from the QA403, triggered events is what I was looking for (on/off transition etc ) .

Any idea of the NanoVNA is usefull ?

Thanks

 

[mcdn]

For audio frequency testing of amplifiers there’s not much better bang for buck than the e1da cosmos ADC and REW on a laptop. Add a picoscope 2000 as a usb scope - not a lot of native resolution but you have the cosmos gear for that, and the picoscope software does all the triggering and logic analysis you want. You’ll need a usb DAC as well, there are plenty to choose from.

 

[FrenchFan]

I confirm

E1DA ADC + E1DA scaler + E1DA APU

E1DA ADC: You have several types of ADCs, from grade 0 to grade B.
Prices vary. Ivan selects them based on their quality:
from approximately 250 Euros to 370 Euros.
Maximum sampling frequency: 768 kHz / 32 bits

Residual noise and THD decrease with each grade; "0" is the best.

E1DA scaler: Allows for gains of up to 100 khoms input. The ADC
has an input resistance that depends on these gains, resulting
in a low input resistance.

~ 200 Euros

E1DA APU: Allows you to surpass professional analyzers for THD and THD,
but for 1000 and 10000 Hz, plus a microphone input and 48 volts.

~ 200 Euros.

TOTAL < 1000 Euros.

The best oscilloscope I know is the REW oscilloscope for audio frequency (LF).

Regarding the triggering, there is indeed a level-based trigger, but
it's not great. Its strength lies in the measurement level. Here's an example:
Visually?

What you see is a theoretical, noise-free 32-bit 192kHz signal.

The ADC can be calibrated in 1µV increments. The maximum frequency with
the E1DA ADC is ~380kHz, which is pretty good for an LF oscilloscope.

 

[ADanalog]

Interesting looking combo.

Microphone input : Any idea if the REW can use standard input from audio recorder like the Tascam X8 (it can output on USBc) ?

What source for D/A signal generator?
Is that also being driven by the REW ?

Thanks

 

[FrenchFan]

Tascam X8, I think so, for me it recognizes pretty much anything,
but I'm on Linux. You can use your PC's microphone input for
your tests; you'll have to calibrate it yourself.

The best thing is a high-performance DAC. I have a Topping D50III,
which is in the high range of DACs for THD and THDN, but many
recent DACs are more than adequate.

You'd have to add 250 Euros to your investment; you'll s
till be under 1000.

The USB signal can be generated by REW without any problem;
it has a built-in multifunction generator, which you can see
in the image sent.

There are also online generators on the internet and even
frequency generator apps for phones.

Personally, I use an "octave" script that I created, since I
understand its parameters.

I think you'll have everything you need, except for high
frequencies, but I don't know what you want to do with that.

 

[EERecordist]

The Quant Asylum has testing software similar to REW & Multitone Analyzer. With REW, the E1DA ADC everyone mentions and their 9039S for a DAC are both very inexpensive. The next step up is the "budget" AP https://www.audiosciencereview.com/forum/index.php?threads/audio-precision-apx516b-review.52335/.

A digital sampling scope can catch transients. A non-inductive power load for speaker amplifiers, and a variac, are useful. Desoldering tools. A calibrated microphone like the UMIC-1 used with REW.

There is a whole test bench topic.

 

[nagster]

I recommend the QA403 + standalone oscilloscope configuration.
Repeating comprehensive measurements with a sound card would be a pain.

Balanced/unbalanced input/output with built-in autoranger and no voltage calibration required.
Maximum input voltage: ±40Vrms / 56Vpeak, Zin SE: 100kohm, BAL: 200kohm. A/D and D/A synchronization.
If you want to use REW, MTA, ARTA, etc., please add an ASIO driver. Measurements are performed by dedicated software by default.
If you want to check around -120dBc, please add the E1DA APU and LPF.

Standalone oscilloscopes are still useful and reliable, and modern models offer a lot of functionality. I'm a worrier, so I also want to check for any abnormalities in the MHz range.
I'm usually very spoiled by the APx555, but the oscilloscope is still placed in the most convenient location.

 

[ADanalog]

Thanks or all the advice

Going to do some more reading, I was not planning to measure anything at a -120dbc , and the convenience of the QA403 is undeniable ( I saw that there is also a 2nd SW package that people are using for the device )

It is nice to have several options - but yeh, I think I got a direction and the budget that I placed seems right.