Chord Hugo and CAP2100

[LED14]

Hello People,
I have the CAP 2100 and love it.

I have a question about connecting the Chord Hugo to it.

As recommended (by the Hugo people) I'm connecting it to the amp in power amp mode (input named SSP) and use the volume control on the Hugo/Jriver.

Because the gain on the Classe is so strong I'm effectively running the Hugo at very low output lever - the volume dial is red - otherwise it's too loud.

I read in a review that it's a small issue with the amp and they recommend using offset to lower the input volume all the way - 10db - I've done it and now I can run the Hugo at a higher output voltage but I'm nit sure if this lowers the SQ - i.e. the amp is using attenuation and thus lowering the volume but also reducing the SQ... I've tried comparing teh two but can't really make up my mind the differenc is tiny but I feel with 10db offset the sound is a little less 'open'.

Any thoughts would be appreciated.

My system is:
HTPC -> Chord Hugo -> CAP 2100 -> B&W CM10S2

Thanks!

[TomScrut]

I wouldn't say it's an issue with the amp, all Classe amps have a 29dB gain which is pretty much standard or thereabouts. I would say you would be best off with the Hugo as loud as possible and the Classe doing the pre amp work. In bypass it will still go through the pre amp stage so you aren't gaining anything by using the digital volume. If it was directly into a power amp then there would probably be a different conversation to be had but you won't be avoiding the volume control circuitry in the CAP.

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[TomScrut]

Your CAP doesn't have the phono stage does it? You aren't running it through that by accident are you? That would cause you that problem (and maybe a fair bit of clipping?).

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[TomScrut]

Also (another thing that has occurred to me) is that when I have JRMC configured to control the volume on my CP800 my usual volume levels of about -15dB on the CP are not very far along the slider in JRMC about a third perhaps. Considering that third of volume control has gone from -99dB to -15dB and the second two thirds then correlates to the last 29dB of -15dB to +14dB, it appears that the slider is an absolute scale rather than logarithmic and therefore the second half of the slider gets very loud very quickly! This might be the issue. It doesn't bother me as I use the CP to change volume anyway.

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[LED14]

Thanks Tom (did we meet at another more local forum? ;-)

I'm using the power-amp mode by renaming the input SSP - I've heard noticeable difference (improvement) when using this method compared to going via the pre-amp with the Hugo at line volume. So I'm pretty sure the pre amp circuitry isn't engaged - at least as long as I don't use the 'offset' setting, I think.

When I use the offset (-10) and turn on the volume on the Hugo I think the sounds is a little constrained(?) so could be that the amp than engaged the pre-amp circuits?

EDIT:
Here is a link to the review I mentioned, take a look at the lab notes on the side:

http://www.audiostars.lv/aud/images/CAP2100_HFN_Aug.pdf

thanks!

[TomScrut]

I thought it would all go through the pre amp regardless of SSP pass through, but I could be wrong! That does look very high, I'm sure my friend doesn't suffer the same issue on either SSP or normal listening. Is the firmware up to date? The easiest way to check this is whether you can go to relative volume mode. IIRC the older FW only had absolute. That could be part of your issue perhaps?

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[TomScrut]

Just been on the Classe website. Check your FW version. It looks like the latest release (still 6 years old) corrects a unity gain issue. My friend needed to upgrade his when he bought his last year so it wouldn't surprise me if yours is out of date. You just need a Windows machine and a serial connection (USB to serial will do)

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[LED14]

Thanks Mate,
My version is 1.4.0 build 094 - so I guess I could use an upgrade too... I'll get the cable.

What exactly is this relative volume thing? Unity gain?

BTW
Do you know if the max volume setting in normal operation is also effective when in power amp mode?

Thanks

[TomScrut]

Yes the new version sorts out the unity gain issue. I think you will have relative volume on your version. Relative is the volume in dB relative to unity gain. Absolute is 0-100 on volume scale. It should be set at 0dB when on unity gain.

I think that the measurements from HFN are to do with a bug to be honest and you are experiencing the JRMC volume slider issue I have with my CP800.

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[LED14]

Thanks Tom,
I did the update bit no major change? I don't see any option for relative volume and it seems the power amp mode works as it did before?

I made sure the version was updated in the settings.

Thanks!

[TomScrut]

It will still work the same as before but is the gain as loud? I think you are confusing an issue HFN had when they reviewed it with the fact that the JRMC volume control is very sensitive! IIRC relative volume is in the volume settings. I aren't sure of the nature the bug fixed by the update was except it covered an inconsistency!

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[LED14]

Hello Tom,
I'm not sure I understand the Volume issue in JRMC?

My Jriver is set to 'internal volume' and I use the Hugo's physical volume control to set the top level, then reduce (or change it) appropriately with the app on JRMC. The volume can never be higher than the physical volume control on the Hugo (unless I turn that louder, of course).

I'm using the Classe in Power Amp mode (SSP) and set JRMC to also normalize volume across tracks.

I've done the update but don't see any difference in the power-amp mode (still very strong) and no relative volume...?

Thanks mate,
Please do share your thoughs,

[TomScrut]

Got you. Sorry I thought you were using the volume slider in JRMC.

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[LED14]

Got you. Sorry I thought you were using the volume slider in JRMC.

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No worries,
Any other ideas are welcome!

[LED14]

Hello Again,
I've made some progress by lowering the internal volume in JRMC and increasing the Hugo to 'Azure' level (about 1v voltage). Do you guys know what would be an ideal voltage level for the Classe at power-amp mode?

Thanks!

[TomScrut]

The input voltages will probably be in the manual but then you can probably do a calculation to account for the extra gain it gives that you were talking about.

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[LED14]

Thanks Tom,
I looked at the manual but couldn't find any indication...
And to be honest didn't understand a word from the rest of your advice... ops:

Care to take a guess about the voltages? What happens if the single is too strong?
Using low (around 30) volume via JRMC gives me lots of headroom to play around with these and the sound already sounds better compared to my previous 0.1v...

Thanks!

[TomScrut]

Clipping is what will happen!

I think it may be something like 1 or 2 volts, if you then knock 10dB off for your extra gain that leaves you at 0.1 or 0.2v. But the 10dB is kind of irrelevant all it means is you are making the Hugo attenuate the signal rather than have the volume set lower elsewhere.

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[TomScrut]

I think you are probably on your best settings, but just make sure that the volume doesn't accidentally get put too high on JRMC!

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[LED14]

Thanks Tom ;-)

I added the volume limited in JRMC so hopefully no-one will blow the speakers/house! ;-)

[LED14]

One last question - unrelated but we are all friends here - what's the most elegant way of hooking a sub to the cap2100? I believe the tape outs would be good? Are they active when in power-amp mode?

Thanks!

[LED14]

The input voltages will probably be in the manual but then you can probably do a calculation to account for the extra gain it gives that you were talking about.

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Hey Tom,
I took another look at the manual and found this:

Maximum input voltage (I'm single ended for now)
3.8Vrms (single-ended)
7.8Vrms (balanced)

Voltage gain range:
-100dB to +14dB

Sensitivity (SSP input)
0.5Vrms for rated output (single-ended)
1.0Vrms for rated output (balanced)

In the CA-2100 manual (the power amp the Cap2100 supposedly has inside) I found this:

Voltage gain
29.1dB

Does this help make an educated guess about the ideal voltage of the Hugo into the classe?

Thanks mate!

[TomScrut]

Well that to me means that you want to be inputting less than 0.5V, but that will be the case if you only have 30 as your volume in JRMC.

The difference between 0.5v and 3.8v is just less than 8dB, which may be the gain that they were talking about in the review.

If you had a CP500 on HT bypass and a CA2100 you would get 29dB gain, but I aren't sure this is the case with the CAP as this would go against what you have said so far IIRC.

No idea about the tape outs. Get a sub with high level inputs? Alternatively get some Y splitters

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[LED14]

Well that to me means that you want to be inputting less than 0.5V, but that will be the case if you only have 30 as your volume in JRMC.

The difference between 0.5v and 3.8v is just less than 8dB, which may be the gain that they were talking about in the review.

If you had a CP500 on HT bypass and a CA2100 you would get 29dB gain, but I aren't sure this is the case with the CAP as this would go against what you have said so far IIRC.

No idea about the tape outs. Get a sub with high level inputs? Alternatively get some Y splitters

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Thanks Tom,
Maybe I'm missing something, but isn't 'proper' line level 2v? Shouldn't I aim there? Also what does the 'maximum input voltage' (3.8v) means? That this will clip? of that the amp will be working at full capacity?

PS
Here is the Hugo volume chart, it may mean more to you than it does to me:


Many many thanks dude, I am grateful for your help!

[TomScrut]

There may be standards but nothing really set in stone. If you go over 3.8v it will clip. This may be the same with 0.5v in power amp mode. If I were you I would try spring green as this is the closest match, or just green perhaps. The thing is it boils down to whether the JRMC volume sounds better than the Hugo volume. The JRMC volume is 64 bit so basically its transparent to the point you won't notice it. The Hugo one may only be 32 but which I believe can make an audible difference if there is a lot of attenuation as truncation occurs. If you limit the volume in JRMC you should be safe!

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[LED14]

Hello guys,
one suggestion I got was to use cheap fixed line level attenuators between the Classe and the Hugo... What do you think of this?

[TomScrut]

Never tried them. They work but not sure if they affect SQ.

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