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Topping Pre90 Review (preamplifier)

mocenigo

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I'm not sure to understand the relation between the amp input impedence and the value a preamp offer vs the DAC volume control.

Some DACs have a relatively high output impedance - as high as 200 or 300 ohms. Some amplifiers, for instance some tube amps and also some class D modules, have a low input impedance, as low as 2500 ohm. If the ratio of sink input impedance over source output impedance gets close to 10 or lower than you may have as a result that the frequency response is not very linear, i.e. you may experience coloration of the sound, amongst other things. In this situation a preamp can help, since they are usually designed to have a high input impedance and a low output impedance.
 

Grael

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Well, don't forget that this particular Pre90 preamp has 2kOhm input impedance for its XLR inputs.

Its strength is the perfectly transparent level ajustement -99db to +16db
 

geekosa

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Some DACs have a relatively high output impedance - as high as 200 or 300 ohms. Some amplifiers, for instance some tube amps and also some class D modules, have a low input impedance, as low as 2500 ohm. If the ratio of sink input impedance over source output impedance gets close to 10 or lower than you may have as a result that the frequency response is not very linear, i.e. you may experience coloration of the sound, amongst other things. In this situation a preamp can help, since they are usually designed to have a high input impedance and a low output impedance.
Thanks for the explanation.

I can see Su-9 DACs has 200 ohm impedence, vs 21 ohms for the PRE90, which gives the Pre-90 an advantage.
 

mocenigo

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Thanks for the explanation.

I can see Su-9 DACs has 200 ohm impedence, vs 21 ohms for the PRE90, which gives the Pre-90 an advantage.

OTOH the input impedance of the Pre90 is quite low itself (which is an exception and a bit weird).
 

pseudoid

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This is a review and detailed measurements of the Topping Pre90 balanced and unbalanced preamplifier. It was kindly sent to me by the company. The base preamplifier with ability to switch between RCA and XLR inputs costs US $599. There is an extension that gives you four (4) more inputs (three balanced and one unbalanced) for another $250.
This must be one of Topping's cash cows. 30 months have passed since the initial review and the price has not budged on aliexpress.
Someone local [:facepalm:] is asking $1k ForSale... used...
 

iLoveCats

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This must be one of Topping's cash cows. 30 months have passed since the initial review and the price has not budged on aliexpress.
Someone local [:facepalm:] is asking $1k ForSale... used...
Other than the remote range, which can be solved with an IR extender, I don't think there's been one problem with the thing. It's forever gear to me, same with the matching DAC.
 

pseudoid

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Other than the remote range, which can be solved with an IR extender, I don't think there's been one problem with the thing. It's forever gear to me, same with the matching DAC.
Then, you ask why @Kal Rubinson would want to sell it.;)
imo; The combo is like a portable standard-bearer.
 

Lefteris

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I bought a second-hand pre90 recently only to find out there is an issue with the remote control. Need to be really close to the pre for any action to take place, volume/input change.
Has anyone else had the same issue? What did you do to overcome?
 

amper42

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I bought a second-hand pre90 recently only to find out there is an issue with the remote control. Need to be really close to the pre for any action to take place, volume/input change.
Has anyone else had the same issue? What did you do to overcome?
Unfortunately, the pre90 remote isn't very good for distance. You might try aiming directly at the middle to the pre90 with the remote and see if that helps. It's a poor remote design. You can also replace the remote battery and see if that helps. Even when my Pre90 was brand new the remote required laser focus on the unit from 10 feet. My RME ADI-2 remote is significantly better for distance use.
 

iLoveCats

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I bought a second-hand pre90 recently only to find out there is an issue with the remote control. Need to be really close to the pre for any action to take place, volume/input change.
Has anyone else had the same issue? What did you do to overcome?
They are all like that, it's not just yours. Buy this IR repeater from amazon. BAFX Products - All-in-One Infrared IR Repeater Kit/Remote Control Extender Cable / 1, 2 or 4 Device Contro (1 Device) https://a.co/d/ikdwwKr
 

iLoveCats

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Hi @iLoveCats do you believe the issue is with the remote or the receiver? Did you try a universal remote?
I think it's the remote blaster is too recessed and the receiver in the Pre90 is off center/partially covered if you shine a flashlight in the front. I could never find the right remote codes for a programmable remote so I got a learning remote called a Sofa Baton from Amazon and learned it to the original Pre90 remote. It didn't really perform better, the distance was better but it needed to be within probably 15 degrees of center. With the sofa baton remote and the IR repeater I can control the volume from any angle maybe 25 feet away in my kitchen.
 

Lefteris

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I think it's the remote blaster is too recessed and the receiver in the Pre90 is off center/partially covered if you shine a flashlight in the front. I could never find the right remote codes for a programmable remote so I got a learning remote called a Sofa Baton from Amazon and learned it to the original Pre90 remote. It didn't really perform better, the distance was better but it needed to be within probably 15 degrees of center. With the sofa baton remote and the IR repeater I can control the volume from any angle maybe 25 feet away in my kitchen.
many thanks for that, the repeater should be arriving soon
 

pseudoid

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Near OT:
I wish there was a (truly) unifying remote control in this universe.
Able to accommodate (be taught or learn) every type of R/C (and codes) ever invented... IR/ RF/ Wireless/ etc.
Even the now defunct Logitech Harmony (family of) remote controls were crappy effort.
SofaBaton should be beaten to death with a baton!:mad:
 
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