Topping Pre90 - Difference in (volume?) output when selecting XLR only vs. XLR + RCA out

[rubin]

Hi all,

I've recently aquired a Topping Pre90. The setup is XLR-only, so:

* Allo USBridge Sig -> USB to ->
* 1x Topping D90SE -> XLR to ->
* 1x Topping Pre90 -> XLR to ->
* 2x Benchmark AHB2 -> Speakon NL2 to ->
* Revel F226BE

I just noticed that when the Topping Pre90 is set to RCA + XLR out (I think the default) the loudness/volume is (much?) higher than when I select XLR only. Why is that?

 

[Jimbob54]

Hi all,

I've recently aquired a Topping Pre90. The setup is XLR-only, so:

* Allo USBridge Sig -> USB to ->
* 1x Topping D90SE -> XLR to ->
* 1x Topping Pre90 -> XLR to ->
* 2x Benchmark AHB2 -> Speakon NL2 to ->
* Revel F226BE

I just noticed that when the Topping Pre90 is set to RCA + XLR out (I think the default) the loudness/volume is (much?) higher than when I select XLR only. Why is that?

@JohnYang1997 may be able to shed some light.

 

[Kal Rubinson]

When set to RCA + XLR, the display shows the level of the RCA output although the XLR output is +6dB. OTOH, when set to XLR Only, it shows the actual XLR output level. It is just a display anomaly.

(based on info from John Yang and already posted elsewhere on this forum)

 

[NTK]

Is the "Vol memory | OUT" enabled and it memorized a different setting? It is ON by default.

 

[rubin]

When set to RCA + XLR, the display shows the level of the RCA output although the XLR output is +6dB. OTOH, when set to XLR Only, it shows the actual XLR output level. It is just a display anomaly.

(based on info from John Yang and already posted elsewhere on this forum)

No, that's not it, it's very audible, it's definitely not a display-only thing.

 

[rubin]

Is the "Vol memory | OUT" enabled and it memorized a different setting? It is ON by default.

View attachment 158277

No, Vol memory IN is enabled in this case. Volume does not change on the display (but does change audibly quite strongly). Note also that nothing is connected to RCA outs.

 

[rubin]

@JohnYang1997 : Could you shed some light on this? I would not expect volume levels to change on the XLR when XLR + RCA are selected (as opposed to XLR only output - haven't tested RCA only output, as I have nothing connected to RCA output).

 

[Kal Rubinson]

No, that's not it, it's very audible, it's definitely not a display-only thing.

How are you making the comparison?
With the XLR+RCA output setting, the XLR output setting of -20dB (or any setting) will be 6db louder than with the XLR Only output setting. In order for them to be at the same level the volume setting of the latter must be -14dB.

To put it another way (quoting John Yang):
When set to balanced/XLR output only, 0dB is 0dB.
When set to RCA + XLR, 0dB is referenced to RCA out, XLR is 6dB louder.

 

[JohnYang1997]

In RCA+XLR output the reference is the RCA output. And XLR output will always be 6dB higher than RCA output.
4V IN at 0dB gives 4V for RCA output and 8V for XLR output.

In XLR only output mode, 4V in is 4V out at 0dB hence it's 6dB quieter at same volume setting.

In practice, you should just use the mode with output you are actually using.

 

[yyzsb]

I was using my Topping Pre90 + D90SE with my Benchmark AHB2 amps and I was able to get a good range of volume adjustment. I was using RCA + XLR output because I also had a subwoofer in that system.

I needed to move the Topping pre90 +ext90 + D90SE to another system (no sub) and connect by XLR output to a CODA #8 amp. I have 2 DACs, a tuner, and a SACD player hooked up to the preamp. With all of the source inputs, I am getting way too much gain and the volume adjustment is very limited in range. So much so that even at the MUTE setting with any input, I am still hearing some sound bleeding through.

My Pre90 is set to XLR OUT only. I have tried the preamp with another amp, the LSA Voyager 350 GAN and it was even worse. The only amp that seems to work for me is the AHB2 monos, but I need those amps elsewhere.

I have tried a Benchmark LA4 preamp replacing the Pre90 and everything works perfectly with the same cables and sources. So I have isolated this to just the Topping Pre90.

Is there anyway to lower the gain on this preamp? Maybe even opening up the case and flipping some internal jumpers?

 

[yyzsb]

Just for laughs I tried using the CARDAS XLR to RCA adapters and connect to the RCA input on my amp. The pre90 was using XLR OUT. In this case, the sound was even a bit louder. I am listening to my tuner with the MUTE setting and it more than enough volume. This is messed up.

 

[RETSELDRIB]

Not sure what Topping thread to revive but this seems a relevant one.

Ive just ordered a Topping Pre90 and D90LE DAC combo. I understand that the D90SE just has MQA whatever that is?

Anyway, I am using a Benchmark DAC2 HGC at the moment for both vinyl and digital (pre-dominantly USB) playback. Very importantly, I have adjusted the attenuation jumpers in the DAC2 HGC so that the volume pot operating range is between 11am and 2.30pm which optimises the gain between the DAC2 HGC and my power amps

Q. Does the Topping Pre90 require that its volume pot is to be used in a certain range to optimise sound quality like the DAC2 HGC? Is it possible to match the volume output of the digital source (D90LE) channel to the analogue (in my case vinyl) output volume like it is on the Benchmark HPA4?

Any other comments welcome.

ps I cant find a download of the respective Topping manuals to familiarise myself but guess that Ill see them when the units arrive tomorrow.

thankyou.

 

[RETSELDRIB]

Hope someone sees this.

Ive just received both units from Electromod - ordered yesterday arrived today - superb friendly service.

I’ve set the pre90 so that it remembers the output volume output of the respective inputs - I have the D90 on the XLR and my phonostage on the RCA.

What I don’t understand is the reason for the C1 and C2 buttons which remember it seems to me the same thing? Can anyone advise possibly?

 

[essence]

What I don’t understand is the reason for the C1 and C2 buttons which remember it seems to me the same thing? Can anyone advise possibly?

Those are save states for different configuration (volume, output etc) settings.

 

[Pulkass]

Is the "Vol memory | OUT" enabled and it memorized a different setting? It is ON by default.

View attachment 158277

First of all. How do l set input RCA only and output RCA only. I press the damn remote. I don't succeed. I want high volume. No damn memories !!!

 

[Kal Rubinson]

Have you read the manual? Each is selectable and will stick until changed.

 

[Pulkass]

Have you read the manual? Each is selectable and will stick until changed.

Thanks. Yes l have. But difficult for me to set it.

 

[Kal Rubinson]

Thanks. Yes l have. But difficult for me to set it.

Sorry to hear that.