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Batting ? Bating isn't a word in that context . And what about you being in a 'fray'? This isn't fight club .to "bat" - two people having an exchange. (e.g., tennis)
Batting ? Bating isn't a word in that context . And what about you being in a 'fray'? This isn't fight club .to "bat" - two people having an exchange. (e.g., tennis)
I've done that, but I didn't find it very informative.People who want to explore input impedance issue of Pre90 can go to this thread https://www.audiosciencereview.com/...-ares-ii-topping-pre90-impedance-issue.34939/
I looked and could not find any balance control. Correct me if I am wrong. ThanksDoes it have a balance control?
EDIT: the manual (which is just a sheet), seems to imply that balance can be adjusted from +10 dB to -60 dB:
http://www.tphifi.net/drivers/pre90_ext90_manual.zip
Are you sure that the A70 Pro uses TPA6102A2 and not transistors?I've always found the Pre90 interesting. I ended up with an A70 Pro because it was able to be a preamp + headphone amplifier for me. I do have two LA90Ds - having all 90s would have looked so nice. If I didn't buy silver amps and black everything else it would have looked nice too - oh well.
I like how the Pre90 has three full stages for the preamp. The TPA6102A2 (current amplifier) is used in both the Pre90 and A70 Pro (plus almost all their other HPA), but the way things [PCB traces] look (also+ the way I've observed operation), the A70 Pro's 6102A2s only go to the headphone outs while the Pre90s [obviously] go to the XLR/RCA outs- meaning the A70 Pro's XLR and RCA outs are driven by probably the output of OPA1612 through multiple surrounding 50 ohm resistors (given RCA output impedance spec is 50 ohm, XLR 100 - it tracks!)
I wonder if I could make the output from my A70 Pro more like the Pre90, turn its balanced headphone out to XLR somehow..
The below graphic is from the 1612s datasheet, it's got me wondering if it's generally bad to drive op amps from extremely low impedance (like 0.003 ohms). Most things are 50 to 600 -I've even seen as high as 2,000. I don't know what's listening first inside the LA90 Discrete (it's permanently hidden in epoxy or something), but it could be this 1612, or some other extremely low distortion opamp
View attachment 450595
Yes, 100%.Are you sure that the A70 Pro uses TPA6102A2 and not transistors?
I was never sure about the A70 Pro, as I only saw the board with the heatsink and Topping didn't mention the TPA6120A2 anywhere.Yes, 100%.
OPA1656 (probably input)
OPA1612 (probably TPA6102A2 and outputs)
TPA6102A2 (headphone outs, there are 4 of them I think channels are separated to one under each
View attachment 450604
Each one of those 4 surface mount resistors you see to the immediate right of the heatsink, I believe, are 2.2 ohm for the outputs. Top 2 are one channel, bottom 2 are the other.
6120 #1 L+R = L +
6120 #2 L+R = L - (opposite)
6120 #3 L+R = R+
6120 #4 L+R - R- (opposite)
For single ended just + are used with ground (L- above isn't ground, it's going to -2V when L+ is at +2V
I was never sure about the A70 Pro, as I only saw the board with the heatsink and Topping didn't mention the TPA6120A2 anywhere.