Topping LA90 Discrete Amplifier Review

[Sash]

Sorry if this was asked and excuse my ignorance I'm just getting into this world of hi-fi.
I am building a cinema/music setup and I wanted to use the LA90D in bridged mode connected to an AVR. I contacted Topping to make sure this is OK and they said they recommend an actual balanced input. I specifically asked about RCA-XLR connection and they answered with:

It is not recommended to connect a balanced to an unbalanced. Balanced to unbalanced will have an impact on performance. It is possible that will work, but there is also the possibility that there will be DC voltage. Simply put, using it in this way may produce some popping sounds, which normally won't damage the LA90D or other devices, but will affect the listening experience.
(We are not responsible for any damage caused by improper use of the product.)

I'm still doubtful but I am not knowledgeable enough to answer my question on my own. Is there any merit in what they are saying? Can I still go this route of AVR with RCA pre-outs to a pair of LA90Ds in bridged mode - into my LR speakers? Thank you!

 

[Sokel]

Sorry if this was asked and excuse my ignorance I'm just getting into this world of hi-fi.
I am building a cinema/music setup and I wanted to use the LA90D in bridged mode connected to an AVR. I contacted Topping to make sure this is OK and they said they recommend an actual balanced input. I specifically asked about RCA-XLR connection and they answered with:

I'm still doubtful but I am not knowledgeable enough to answer my question on my own. Is there any merit in what they are saying? Can I still go this route of AVR with RCA pre-outs to a pair of LA90Ds in bridged mode - into my LR speakers? Thank you!

If the manufacturer says that is not recommended to connect it to an unbalanced source you better listen to them.

 

[Down South]

Sorry if this was asked and excuse my ignorance I'm just getting into this world of hi-fi.
I am building a cinema/music setup and I wanted to use the LA90D in bridged mode connected to an AVR. I contacted Topping to make sure this is OK and they said they recommend an actual balanced input. I specifically asked about RCA-XLR connection and they answered with:

I'm still doubtful but I am not knowledgeable enough to answer my question on my own. Is there any merit in what they are saying? Can I still go this route of AVR with RCA pre-outs to a pair of LA90Ds in bridged mode - into my LR speakers? Thank you!

The solution is to use adaptors RCA to XLR. I have the same 'problem' in that all my equipment is RCA out. Having said that with using adaptors for 6F8G tubes in 6SN7 gear it hasn't 'noticebly effected the sound.

 

[Sash]

Thank you both for the answers!

The solution is to use adaptors RCA to XLR. I have the same 'problem' in that all my equipment is RCA out. Having said that with using adaptors for 6F8G tubes in 6SN7 gear it hasn't 'noticebly effected the sound.

Hmm, what would the adapter do other than make the connection possible? I specifically asked them about this (i.e. using RCA to XLR cable) but since the signal would inherently be unbalanced since it comes out of the RCA they answered with the quote above. From my understanding how they phrased it it would essentially eliminate the possibility of this amp to be used with any AVR other than preprocessors since all AVRs have RCA preouts. I just don't know enough about the specifics to comprehend why that would be and that's why I want to understand it better which would ultimately help me with my purchasing decision.

 

[Down South]

Thank you both for the answers!


Hmm, what would the adapter do other than make the connection possible? I specifically asked them about this (i.e. using RCA to XLR cable) but since the signal would inherently be unbalanced since it comes out of the RCA they answered with the quote above. From my understanding how they phrased it it would essentially eliminate the possibility of this amp to be used with any AVR other than preprocessors since all AVRs have RCA preouts. I just don't know enough about the specifics to comprehend why that would be and that's why I want to understand it better which would ultimately help me with my purchasing decision.

I suggest you take a look at the info available online as I did. The answer from Topping isn't an intelligent one - why not put the question to Amir?

 

[Sokel]

I suggest you take a look at the info available online as I did. The answer from Topping isn't an intelligent one - why not put the question to Amir?

I don't think that this has to do with intelligence,engineers and manufacturer must know their device better than anyone.
If they say that is intended to be used only balanced they know better.
And it's not the only Topping strongly suggested NOT to be used in another way.

 

[nagster]

Sorry if this was asked and excuse my ignorance I'm just getting into this world of hi-fi.
I am building a cinema/music setup and I wanted to use the LA90D in bridged mode connected to an AVR. I contacted Topping to make sure this is OK and they said they recommend an actual balanced input. I specifically asked about RCA-XLR connection and they answered with:

I'm still doubtful but I am not knowledgeable enough to answer my question on my own. Is there any merit in what they are saying? Can I still go this route of AVR with RCA pre-outs to a pair of LA90Ds in bridged mode - into my LR speakers? Thank you!

As a premise, those who cannot judge by themselves should follow the manufacturer's instructions.
However, I am concerned about "Balanced to unbalanced". You guys may not be talking to each other.
Although,
"unbal out ==> bal in" should be fine or only slightly degraded if you use a suitable conversion cable. Unless there is severe common mode noise such as hum.
For example, the maximum output of PA5 dropped to about 80% and the THD+N ratio deteriorated by 0.0001%.

Topping PA5 Review (Amplifier)

Useless as you do not know the input impedance of the amp and what blocking cap is in these. Amps run from 10 to 50K typically. You can get a simple crossover from folks like Rolls. Not as bad as it looks. You can DIY a really good crossover like the X-Kitx. I agree with your want. A really...

www.audiosciencereview.com

"bal out ==> unbal in" may cause non-negligible degradation or system failure if done with conversion cables/connectors.
For example, the D10B had a THD+N ratio degraded by 50dB and a dangerous DC offset.

Topping D10 Balanced Review (USB DAC)

It looks (in my case) ,that the onboard switching power supply + 5.65V / -5.6V, which supplies the output analog circuits (3 OA) behind the DAC, fails / does not start ..). That PSU is powered from 5V inputs. The all other onboard sources (3.3V, 1.2V, 1V) start up normally, they are linear (not...

www.audiosciencereview.com

 

[Ziofrenko]

Better crosstalk performance on LA90, and only few watt of improvement on LA 90D, make old LA90 better in stereo operation (5W on 36, and 14 on 56, is not a upheaval) and new La90D better on bridged operation.
This in my opinion.
No problem of SPL in nearfield listening with KEF iQ30 and old LA90.

 

[Ziofrenko]

The transistor clamping plate could easily be replaced with a piece of aluminium.

Good idea to blow up condenser and resistor which are very close...
Transistor ar screwed to the heatsink.
Dont't need another heatsinks...

 

[ampguy]

I just wouldn't do it. Reasons could be a combination of small issues, but I'll name a couple - at same volume amp may run hotter, cable may not be made right, noise potential, ground on some amps is not earth ground as some rca to trs connectors may be designed, balanced only design cannot know if voltage is on the rcas. Just don't do it. Buy an amp designed for rca line level, there are thousands of options there

 

[YesChickenNuggets]

I eyed the AHB2 for so long but then Topping came along and gave me something far better for far less money.
I can objectively say I have "arrived" at the ultimate system considering all scientific facts. Still the whole system is still a tiny bit below 10.000 €. Most of that thanks to ASR.

Yea, honestly, a pair of these make the AHB2 completely obsolete.

It's GG. Even Purifi/ Hypex wouldn't make any sense for the price. Just buy 2 of these.

 

[b7676]

Thank you both for the answers!


Hmm, what would the adapter do other than make the connection possible? I specifically asked them about this (i.e. using RCA to XLR cable) but since the signal would inherently be unbalanced since it comes out of the RCA they answered with the quote above. From my understanding how they phrased it it would essentially eliminate the possibility of this amp to be used with any AVR other than preprocessors since all AVRs have RCA preouts. I just don't know enough about the specifics to comprehend why that would be and that's why I want to understand it better which would ultimately help me with my purchasing decision.

There was a thread this month discussing DC filtering, the guy wanted his diy speaker system capable of handling DC.
A preamp like the topping L70 that will take stereo rca and produce a differential / balanced signal.

 

[DrDen]

There was a thread this month discussing DC filtering, the guy wanted his diy speaker system capable of handling DC.
A preamp like the topping L70 that will take stereo rca and produce a differential / balanced signal.

Surely better than any fancy conversion cable. Moreover, it’s headphone amp.

 

[Down South]

I just wouldn't do it. Reasons could be a combination of small issues, but I'll name a couple - at same volume amp may run hotter, cable may not be made right, noise potential, ground on some amps is not earth ground as some rca to trs connectors may be designed, balanced only design cannot know if voltage is on the rcas. Just don't do it. Buy an amp designed for rca line level, there are thousands of options there

check out the thred I started on diyaudio - RCA to XLR

 

[aphysically]

came home to random pops from my left speaker LA90D while it's powered on. All the connections look solid, so time to start replacing cables although I'm skeptical

 

[aphysically]

came home to random pops from my left speaker LA90D while it's powered on. All the connections look solid, so time to start replacing cables although I'm skeptical

replaced everything except the power supply cable, which I tried reseating and running through a regulated power supply and all popping remained, so looks like my amp died :\. I guess I can convert my other mono amp to stereo. What is SOTA in class D these days? Happens with no input to the LA90D as well

 

[Doodski]

replaced everything except the power supply cable, which I tried reseating and running through a regulated power supply and all popping remained, so looks like my amp died :\. I guess I can convert my other mono amp to stereo. What is SOTA in class D these days?

Buckeye Amps has the class D gear with the best prices if you want a simple design and case without the fancy milled face plates and other stuff.

 

[aphysically]

Buckeye Amps has the class D gear with the best prices if you want a simple design and case without the fancy milled face plates and other stuff.

Thanks, it looks like the 2-channel Hypex NCx500 Amplifier is my best bet?

 

[Doodski]

Going off memory these are good stuff, the best I think for class D.

Buckeye Amps

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

Buckeye Amps

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

 

[aphysically]

Going off memory these are good stuff, the best I think for class D.

Buckeye Amps

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

Buckeye Amps

Buckeye Amps utilizes the most advanced audio amplifier technologies available. Authorized seller for Hypex and Purifi Class D amplifiers. Based in the US. Free shipping and worldwide service!

www.buckeyeamp.com

Thanks went with the 2 channel ncx500. It's preorder shipping in May, so I can use my working LA90D in stereo mode until then