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Topping LA90 Review (Integrated Amplifier)

Rate this amplifier:

  • 1. Poor (headless panther)

    Votes: 27 3.8%
  • 2. Not terrible (postman panther)

    Votes: 48 6.7%
  • 3. Fine (happy panther)

    Votes: 172 24.2%
  • 4. Great (golfing panther)

    Votes: 465 65.3%

  • Total voters
    712

Doodski

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Feyire

Hello, Friend! Can you reccomend to swap original thin white chain from XLR-base to "main motheboard" with audiophile one? :)

Picture was taken from www.audiophonics.fr
That thin white chain is called a FPC (flexible printed circuit). No, you will not hear a improvement if you replace it with something heavier and more audiophile looking.
 

TheMadcap

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At 86 sensitivity , i would want two in mono mode . That's my take. Just one may not be ideal. I have my most powerful amp on my Kef Ls50's that I still use. And they are 86-87 sensitivity I think and they need it. The amp is 220 watts per channel.
What is your amp. I thought the same, and didn't have budget for the two mono La90, so I bought a used rega elicit r.
 

PeteL

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That thin white chain is called a FPC (flexible printed circuit). No, you will not hear a improvement if you replace it with something heavier and more audiophile looking.
I think he is reffering to the ribbon cable. I don’t see any FPC, where do you see that?
 

Doodski

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I think he is reffering to the ribbon cable. I don’t see any FPC, where do you see that?
We just called those FPCs and would be done with it. Potato... tomato... I suppose technically you are correct there is no circuit onboard. :D
 

PeteL

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We just called those FPCs and would be done with it. Potato... tomato... I suppose technically you are correct there is no circuit onboard. :D
If you want, but there is nothing printed neither, just leads and isolation. A FPC looks like that, just a different process
1669078079464.png
 

restorer-john

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If you want, but there is nothing printed neither, just leads and isolation. A FPC looks like that, just a different process
View attachment 245189

They have always been known a FPC ribbons. Not ribbon cable. Ribbon cable is completely different and always has been too.

This is ribbon cable:
1669079557516.png


Later ribbon was called IDC where insulation displacement connectors were fitted to each end, but the cable itself, is ribbon.

Sometimes the FPCs are vapor deposited and printed, other times etched, other times pressed and they often have some active and/or passives on the FPC and they are true flexible printed circuits. It was first started in the 1980s with companies like Matsushita experimenting with super thin and flexible printed (yes printed) circuits with printed resistors along with early SMD devices and passives.

The miniaturization race in walkmans and car audio, drove flexible printed circuits, along with video cameras/still cameras. Just about every CD player has FPCs connecting the laser head/focus assembly to the main board or the mech PCB. @Doodski would have seen a million of them, just as I have. Often the LD power adjustment pot and CC active circuit is on the FPC.
 

PeteL

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They have always been known a FPC ribbons. Not ribbon cable. Ribbon cable is completely different and always has been too.

This is ribbon cable:
View attachment 245194

Later ribbon was called IDC where insulation displacement connectors were fitted to each end, but the cable itself, is ribbon.

Sometimes the FPCs are vapor deposited and printed, other times etched, other times pressed and they often have some active and/or passives on the FPC and they are true flexible printed circuits. It was first started in the 1980s with companies like Matsushita experimenting with super thin and flexible printed (yes printed) circuits with printed resistors along with early SMD devices and passives.

The miniaturization race in walkmans and car audio, drove flexible printed circuits, along with video cameras/still cameras. Just about every CD player has FPCs connecting the laser head/focus assembly to the main board or the mech PCB. @Doodski would have seen a million of them, just as I have. Often the LD power adjustment pot and CC active circuit is on the FPC.
Thanks John, I've learned something, but to be totally honest, I do not see the fundamental difference between the picture you showed me and what I can see in this amp, beside the color coding and the gauge of the conductors, but the picture referenced was really small and unclear. Is this only a size thing to determine how it's called? Not doubting what you say just curious how you differenciate the 2 visually.
 
Last edited:

restorer-john

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Is this only a size thing to determine how it's called? Not doubting what you say just curious how you differenciate the 2 visually.

Ribbon is usually multi stranded copper wire (not always) whereas the other is flat copper track.

There's also ribbon which is single core (round). But to my knowledge pretty much most (definitely not all) of the ribbon that connects to IDC is stranded internally.

Also, ribbon is not designed for constant flexing back and forth, whereas the FPC often is. As @Doodski and I have seen many times, it often fractures if flexed too much/often. One of the most common issues with CD players was the flex (FPC) links going intermittent or breaking altogether right on the bends or flex points.

And, because it's not copper per-se, repairing them is pretty much not possible- soldering to this weird printed conductor rarely works. I've replaced impossible to get FPC links in transports with looms made of litz wire, stripped out of ear-bud cables. That never breaks. Hope that makes sense.
 

PeteL

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Ribbon is usually multi stranded copper wire (not always) whereas the other is flat copper track.

There's also ribbon which is single core (round). But to my knowledge pretty much most (definitely not all) of the ribbon that connects to IDC is stranded internally.

Also, ribbon is not designed for constant flexing back and forth, whereas the FPC often is. As @Doodski and I have seen many times, it often fractures if flexed too much/often. One of the most common issues with CD players was the flex (FPC) links going intermittent or breaking altogether right on the bends or flex points.

And, because it's not copper per-se, repairing them is pretty much not possible- soldering to this weird printed conductor rarely works. I've replaced impossible to get FPC links in transports with looms made of litz wire, stripped out of ear-bud cables. That never breaks. Hope that makes sense.
It kinda does, In most of the audio equipment I have come across, those cables have ridges, suggesting just a row of wires not flat track. As I said the picture is very small so can't tell, but to me my first reflex was to think that would look more like this:
1669103940073.png

than like this:
1669104041467.png

1669104106556.png


Is the first one up still ribbon to you? If so, do we have reason to think it's not one of this type in this headphone amp?
 

restorer-john

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The picture of the internals of the LA90 is FPC without a doubt, complete with locking PCB connectors. Not ribbon.

1669105411347.png


This type:
1669105566387.png
 

Sokel

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The picture of the internals of the LA90 is FPC without a doubt, complete with locking PCB connectors. Not ribbon.

View attachment 245252

This type:
View attachment 245253
Yep.
I took me about two months to get some of those from China (first order was lost and they send me another one for free,I got 10 of those for something like 3 euro) so I could connect Khadas with a breakboard to easily integrate with Ian Canada controller.
The description everywhere was "FFC FPC".
 

nUUK25

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Ocay, LA90 gain in mono mode is 15,5 db or 25,2 db ....or as you suggest just try with one amp in stereo as a start and see how it goes at 1/4 of the expence - maybe 4 amps are overkill. Stereo and one amp will give me an idear about quality level at lower and modest audio levels - can always expand later if I feel it is necessary.
I've had just one LA90 for some time (July) and realized that with two the sound might be less constrained. Two month ago I've bridged (mono) two amps, one for each speaker and it works wonders in terms of the past 'constrainment'. Definitely an audio quality ascent ! Now I'm thinking I might gain some improvement with another two LA90 in the setup as my Martin Logan Electromotion speakers are bi-amp capable. I doubt the improvement will be proportional; two to four, but even less are welcome ! The fact that one amp will be dedicated to the electrostatic section and another amp to the dynamic section in itself might reveal more clarity. If I do go for it I will report back here !
 

MitchWolos

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I have a question about the power supply.

I'd like to use some of these in my car. Was considering using Purifi modules in DIY enclosures with large SMPS salvaged from large high-quality car amplifiers that had divorced power supplies and output sections. I believe they're around +60 -60 with reference to ground. Is the power supply simply 63V DC between the two pins? Or are the 3 pins + - and gnd?
 

restorer-john

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You can see on the photos in the opening post that it's bipolar (+, -, GND).
I'm sure this will work. You may not get the same state of the art performance, but the difference will not be audible as long as the substitute PSU is adequate.

Have another look...
 

Bleib

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