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Krell KRC3 low volume / low output voltage ?

Hi everybody,

I’m new to Audiogon so I should introduce myself, but there’s not too much to say. As all of you I do love music and as a mean I try to have systems that suit my taste. What else can I add? Ohh… my English might not be too good, I’ll try to do my best. Anyway you can correct me, no offence!

So my first post is about an issue with krell preamps, especially the KRC3, which is my actual preamp. It appears that I have to crank up the knob to get a loud volume. My power is a Pass Labs X250. First I thought it could be something wrong with my preamp but then I remember I’ve had the exact same problem running a KSL.

On the other hand I don’t have this issue with Classe preamp (model five or model fifteen).

Anyway I’m trying to use a balanced cable between the KRC3 and the Pass but I don’t really feel the 6 db more I should hear (following what is sais in the owner’s manual)… Should I run the whole system through XLR cable (actually I can’t because my Marantz DV-9500 doesn’t have XLR outputs)

So what do you think?
By the way I found an old and similar thread here:
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1101779119&openflup&12&4

Thank you and I hope I can soon help somebody in a forum thread.

James Zep (not my name, just a mix between James Gang and Led Zeppelin, I guess I won’t need to precise my musical tastes…! Don’t worry, I also listen plenty other things…)
jameszep
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Hello James Zep, welcome to Audiogon (I like both bands.:))

Well how loud you have to turn the volume knob depends on several factors. How large your room is, how efficient your speakers are, what you amp's input sensitivity is, how much gain your preamp has and what the output voltage of your source is. As you can see, there are many factors that come into play here.

I don't know how big your room is or how efficient your speakers are. I can't find the Pass X250's input sensitivity. I can see that the Krell KRC-3's gain is only 6.5 dB, which is relatively low for a preamp. I also can't find any information on your Marantz's output voltage.

So, there are many unknowns in this equation. The one known says that 6.5 dB is on the low end of the gain scale for a preamp. For instance, my preamp has 20 dB of gain. So it could be an issue where your KRC-3 just does not have enough gain to mate with the rest of your system. However, it won't hurt your system to run the volume knob at 3 or 4 o'clock. Many folks have the opposite problem, where 8-9 o'clock is blowing them out of the room.

Bottom line, if the system is playing loud enough for you, don't worry where the volume knob is located. If it is not loud enough with the volume cranked all the way up, then you need to look for a preamp with more gain.
jameszep OP
7 posts
 
Hi Jmegropan2

You said:
“However, it won't hurt your system to run the volume knob at 3 or 4 o'clock.”

That’s true and it’s actually pretty precise on low volume sessions, like at night. The KRC3 volume control is quite accurate on that sense…
And as you said it might come from the gain feature, for example my Classe Five (I don’t have that problem with Classe preamps) has 18 db of gain.

Now I was hoping that I could take advantage of this (quote from KRC3 owner’s manual):
“NOTE: When connecting inputs or outputs to the KRC-3, remember that the balanced connections will have 6dB more gain than the single-ended connections. When level matching is critical in your installation, keep this specification in mind.”

But even with an XLR cable between preamp and amp, I don’t feel a difference (though I didn’t have a long listening period through this cable). Do I have to connect the whole system with XLR cable to take advantage of this? (Which means I need to go XLR too between Marantz player and KRC3 and I can’t. Not too bad cause I’m seriously considering an Oppo 105 but I still have to figure out if it would be and upgrade considering I don’t care about blue ray).

Thanks to both of you.
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Jameszep,

I'm not sure if the KRC-3 is fully balanced or quasi-balanced. The manual note may say that you will get +6 dB of gain running balanced, but their spec sheet in the manual does not indicate this. It says 6.5 dB of gain....period.
Most spec sheets that offer balanced and unbalanced outputs would have a spec sheet that states:
Gain - 6.5 dB unbalanced, 12.5 dB balanced

The Krell does not do this, so you would have to contact Krell to find out where the error is in their manual. Is it in their +6 dB note, or on their specification sheet.

If you don't hear a +6 dB difference, I would suspect a quasi-balanced design, which does not provide a +6 dB gain that fully balanced designs do, and that the printing error would be in the +6 dB note that was probably written by a marketing agent. The spec sheet is usually written by the engineering department, and therefore more accurate.
jameszep OP
7 posts
 
Jmcgrogan2,

Printing error from Krell… You might be right but it is a bit surprising.
Once again I’m not having too much time since I bought an XLR cable.
Anyway I called a friend who has also a Krell preamps and he has observed the same volume comportment. And what all of you guys tell me reaffirm that so I just guess they are made this way.

Thank you all.
zd542
5,339 posts
 
I just thought of something you may want to try. Sometimes components have things like buttons and dip switches, either internally or externally, that are used for various reasons. (set gain, bal/se...). I would definitely take the top cover off your Krell and have a look inside. I'm almost positive Krell uses dip switches. It should only take a couple of minutes and would be well worth the effort.
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