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Gain settings AHB2 vs D90SE

rubin

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So from the AHB2 manual, three input gain settings:
  • Low-Gain = 22 dBu (9.8 Vrms)
  • Mid-Gain = 14.2 dBu (4 Vrms)
  • High-Gain = 8.2 dBu (2 Vrms)

From the D90SE manual, two output voltage settings (XLR):
  • 4.2 Vrms @0dBFS (4V mode setting)
  • 5.2 Vrms @0dBFS (5V mode setting)

From my naive understanding, I would think mid-gain on the AHB2 and 4V on the D90SE are the best-matched settings. However, I've heard others proclaim that low-gain (9.8 Vrms) on the AHB2 and 5V (5.2 Vrms) on the D90SE are somehow "better". I would very much like to hear some expert opinion on this and the physics involved. What should be better from a sound quality perspective and why?
 

Jimbob54

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So from the AHB2 manual, three input gain settings:
  • Low-Gain = 22 dBu (9.8 Vrms)
  • Mid-Gain = 14.2 dBu (4 Vrms)
  • High-Gain = 8.2 dBu (2 Vrms)

From the D90SE manual, two output voltage settings (XLR):
  • 4.2 Vrms @0dBFS (4V mode setting)
  • 5.2 Vrms @0dBFS (5V mode setting)

From my naive understanding, I would think mid-gain on the AHB2 and 4V on the D90SE are the best-matched settings. However, I've heard others proclaim that low-gain (9.8 Vrms) on the AHB2 and 5V (5.2 Vrms) on the D90SE are somehow "better". I would very much like to hear some expert opinion on this and the physics involved. What should be better from a sound quality perspective and why?
Edit: I know nothing
 
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rubin

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I'm trying both, I.e., DAC in pre-amp mode + I have a Pre90 that I can stick in-between (in which case I put the DAC in DAC-only-fixed-volume mode).

My problem is: the way you make it sound, it's a preference thing: I want to understand the thinking behind it. Maxing the output from the DAC, I could do 5V (5.2 vrms) into low-gain, in essence utilizing less of the max headroom of the AHB2 (which is totally fine - I don't even want to play close to that loud). I'm trying to understand: "is that BETTER than 4V (4.2vrms) into mid-gain (4.0vrms) and WHY".
 

abdo123

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or would you use the amp for all volume

The ABH2 has no pre-amp function, this is not possible.

@rubin keep the Topping on 4V mode and the ABH2 on Mid-gain.

The 'better' version you mentioned would rob you of 6dB of headroom. Considering that the ABH2 barely outputs any power for its price i would milk it for every Watt it can provide.

UNLESSSS (playing the devil's advocate here) you have like a 105 dB sensitivty horn or some shit like that to the point that with the 4V mode and mid-gain setting somehow God knows how you hear hiss at the horn or something.
 

Jimbob54

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The ABH2 has no pre-amp function, this is not possible.

@rubin keep the Topping on 4V mode and the ABH2 on Mid-gain.

The 'better' version you mentioned would rob you of 6dB of headroom. Considering that the ABH2 barely outputs any power for its price i would milk it for every Watt it can provide.

UNLESSSS (playing the devil's advocate here) you have like a 105 dB sensitivty horn or some shit like that to the point that with the 4V mode and mid-gain setting somehow God knows how you hear hiss at the horn or something.
Ah. Yes, of course.
 
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rubin

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@abdo123 : What do you mean with "Considering that the ABH2 barely outputs any power for its price"? Isn't it so that doing 5V (5.2 Vrms) into low-gain (9.8 Vrms) would only "rob me" of a higher volume level, but give me a higher SNR?
 

abdo123

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@abdo123 : What do you mean with "Considering that the ABH2 barely outputs any power for its price"?

it's 100W @ 8 Ohms for 3000$ before tax. it's basically 30$ per watt. it's insanely pricey but the fact that nothing else beats it makes it 'okay'.

@abdo123 Isn't it so that doing 5V (5.2 Vrms) into low-gain (9.8 Vrms) would only "rob me" of a higher volume level, but give me a higher SNR?

Yes exactly, but the 'Higher S/N' would not be of any use to you if you can't hear the hiss/noise in your system with the 'lower S/N'
 

Oukkidoukki

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So from the AHB2 manual, three input gain settings:
  • Low-Gain = 22 dBu (9.8 Vrms)
  • Mid-Gain = 14.2 dBu (4 Vrms)
  • High-Gain = 8.2 dBu (2 Vrms)

From the D90SE manual, two output voltage settings (XLR):
  • 4.2 Vrms @0dBFS (4V mode setting)
  • 5.2 Vrms @0dBFS (5V mode setting)

From my naive understanding, I would think mid-gain on the AHB2 and 4V on the D90SE are the best-matched settings. However, I've heard others proclaim that low-gain (9.8 Vrms) on the AHB2 and 5V (5.2 Vrms) on the D90SE are somehow "better". I would very much like to hear some expert opinion on this and the physics involved. What should be better from a sound quality perspective and why?
Sound must be pretty extrodinary with that setup, maybe small youtube video later on music playing…
 

laidick

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What if I have a LA4 in between and use it to add +10dB or even +15dB to the signal chain?

So, D90Se 5V + LA4 15dB + AHB2 low gain mode.
 

mononoaware

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I am a lower level to moderate SPL listener.

I would just use Low-gain on the AHB2 and take advantage of the SNR of the D90 by turning up the pre-amp gain that’s what I would do.

I would use medium gain on the AHB2 if the DAC only had RCA outputs.

I don’t really see any issue here, seems quite straight forward to me…
 

kchap

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If you are using the Pre90 then low gain seems to be the best option. The Pre90 can pump out 9 Vrms. If it's DAC out to amp in then mid gain for the amp. For the DAC, 5 V out vs 4 V out will make little difference.
 

poopy

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There will be no issue at all using low-gain mode on the AHB2 with 4V output from D90SE.
If you can choose 5V output (didn't know one could do that with the D90SE), it's even better.
 

Docmoggy

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I am probably wrong here, but I’m running a Topping Pre90 into a AHB2. I set the in and out puts in XLR and with low gain I’m at -11dB to hear anything approaching reasonable at about 2.5m from speaker centers. I switch progressively until in high gain the sound is absolutely terrific and I’m at about -35dB. The sonic revolution is much better by a mile, loads of detail and vocals are life like. At mid and low gain the whole sound goes flatter.

I switch the Pre90 to RCA+XLR output and there is a big gain so that at low gain setting I’m at about -25dB but the sound is still not as good as XLR out and high gain setting on the AHB2.

Given that the Pre90 and AHB2 have very low noise and distortion in the audible range that a high gain setting is better for big 4 ohm speakers?
 

Kal Rubinson

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I switch the Pre90 to RCA+XLR output and there is a big gain so that at low gain setting I’m at about -25dB but the sound is still not as good as XLR out and high gain setting on the AHB2.
If you switch to RCA+XLR output, the displayed gain is what the RCA is providing. Using the XLR output with that setting is actually +6dB over the displayed value because, well, its balanced!
 

Docmoggy

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If you switch to RCA+XLR output, the displayed gain is what the RCA is providing. Using the XLR output with that setting is actually +6dB over the displayed value because, well, its balanced!
The general rule I’ve been told is to stick to the XLR out although I don’t know why- as you say, it’s an XLR output to the power amp.

Having said that why is everybody going for low gain in the AHB2 sensitivity range? I think my speakers need the high gain setting to resolve the detail, but apparently that setting amplifies noise and distortion and isn’t meant for balanced feeds. It’s confusing me.
 

Kal Rubinson

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The general rule I’ve been told is to stick to the XLR out although I don’t know why- as you say, it’s an XLR output to the power amp.
Sure. All I was saying is that the display indicates the RCA output gain and not the XLR output gain.
Having said that why is everybody going for low gain in the AHB2 sensitivity range?
The higher the power amp gain, the more it will amplify any noise it is getting from upstream.
I think my speakers need the high gain setting to resolve the detail,
That is doubtful.
 

Docmoggy

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Sure. All I was saying is that the display indicates the RCA output gain and not the XLR output gain.

The higher the power amp gain, the more it will amplify any noise it is getting from upstream.

That is doubtful.
Well, if my streamer DAC has similar performance to both, my Pre 90 and AHB2 then surely there’s no audible noise to amplify - so I’m on high gain to really give my speakers big juice! There is definitely a significant improvement in spacial resolution in particular when I’m LAN streaming Tidal master option. I’m on low gain streaming from my laptop (PCE). At that position I “lose” 10dB and have to really crank the Pre90 to -20dB. There’s plenty of headroom left, but somehow the sensitivity isn’t matched to the speaker.
 
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aj625

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if you are getting enough volume for most of the time with low gain then stick to it. using low gain will ensure lesser attenuation d90se signal which will give you better s/n ratio from d90se as well as ahb2.
 

Darkscience

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I need to check what gain I am using. I have an RME DAC, LA4, AHB2 into Cornwall Speakers. Any recomendations?
 

kongwee

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I alway try to get safe listening level at half volume. Easier to dial in precise level. Switch gain at AHB2 to allow you to have easier volume control. You don't have to struggle one step up or down most of the time.
 
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