Lightstar Direct XLR Outputs - Low Gain?

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whell
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Lightstar Direct XLR Outputs - Low Gain?

Post by whell » Thu Apr 10, 2008 10:19 pm

On my Lightstar Direct preamp, the balanced outputs seems to be quite a bit less (quieter) than the RCA outputs. When using the balanced outs, I really have to crank the preamp up. I'm using a PS Audio Trio A 100 amp, which has balanced inputs (and yes, I've set the switch on the back of the amp to the XLR inputs).

Is this normal for the Lightstar, or is something amiss?

Thanks!

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by OBI56 » Thu Apr 10, 2008 11:18 pm

Hi Whell. Not sure about your problem, but you should talk to ToyMaker about this and at the same time discuss with him about the serial number of your unit so he can enter it into his Lightstar owners register.
Why let facts or common sense get in the way of your opinions.

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by Toy Maker » Thu Apr 10, 2008 11:54 pm

Greetings, and welcome.

I honestly can't amswer your question, I still haven't even plugged mine in.
My father DaveS has one, but his is still sitting in the box as well.

Ray is the only one actually USING his that I know of...
I'll drag him in here and see if he has any advice on this one.

I did notice the gain switches on the back of my LS amp... I wonder if that has anything to do with the Pre's XLR outputs ?!?!


And yes.. PLEASE go and register in the Lightstar registration thread here:
viewtopic.php?f=62&t=4004
I'd like to track down as many of these units as possible.

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by Magnaryder » Fri Apr 11, 2008 3:00 am

whell wrote:On my Lightstar Direct preamp, the balanced outputs seems to be quite a bit less (quieter) than the RCA outputs. When using the balanced outs, I really have to crank the preamp up. I'm using a PS Audio Trio A 100 amp, which has balanced inputs (and yes, I've set the switch on the back of the amp to the XLR inputs).

Is this normal for the Lightstar, or is something amiss?

Thanks!
I have both of my working Lightstar pieces running in the unbalanced mode... but it's my understading that the sensitivity matching switches on the back of the amplifiers were designed to overcome this problem/issue. The Lightstar Direct is *still* considered to be one of the quietest pres ever made 'in the balanced mode'. Can you raise input sensitivity on your amplifier? That might help. I'll consult the manual and see if I can figure out anything and get back with you.

ray
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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by Dreamer » Fri Apr 11, 2008 3:40 am

Most balanced-output devices (preamps, DACs, etc) have gain pots next to the outputs for proper level matching. This is a "pro" feature, because in a studio, level-matching is KEY tto getting good results, and this practice has carried over to home audio gear that uses balanced outputs too.

I can't speak to your Lightstar issue, but I know on my Benchmark DAC, the XLR outs sound WAY better than the RCA outs (when run into my Krell preamp), and the XLR outs are actually a little louder than RCA. The XLR outs also have gain pots next to them on the backplane, AND the Benchmark DAC also has a set of jumpers inside on the PCB to adjust gain, rolloff and frequency response when using the balanced outs--this unit is TOTALLY studio-quality. It took me a while to get everything dialed in, but now that I have, it sounds even better than it did out of the box, which was FANTASTIC...

Pro-level connections require pro-level tweeking and great cables. If you are using standard, generic "DJ-quality" XLR interconnects, I'd suggest that you bite the bullet and go get some high-end cables. I'm using White Zombie Audio "Zero Point Zero" XLRs between my DAC and Pre, and they are simply astounding--detailed, quiet as all get out, and about as close to a hard-wire connection as you're going to get with cables. And even though they are solid silver conductors with pro-grade Neutrik connectors, they actually cost less than high-end Monsters or AudioQuests...

--Richard
.....HT Rig • Sony STR-DG600 Receiver • Carver M-500t • Sony BDP-S1 • Sony DVP-NS3100ES • Apple Airport Express •
..............................• Martin Logan Scenarios, Logos • Realistic Minimus 7's • Velodyne F-1500b •

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by whell » Fri Apr 11, 2008 6:00 am

Thanks for everyone's input. I'll see if I can get the serial # off the unit tonight. I am using good Audioquest interconnects, so I suspect the issue, if there is one, is elsewhere.

Thanks!

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by DaveS » Fri Apr 11, 2008 11:35 am

This is right from the owner`s manual:

Balanced Output
These provide a true balanceoutput which can be connected to the balanced input jacks of a power amplifier. There is no gain from the balanced or unbalanced inputs to balanced output, only attenuation that is determined by the amount indicated on the front panel.

Unbalanced Output

The balanced signal iside the Lightstar Direct is converted to a unbalanced output by a precision instrumemtation amplifier with a DC servo circuit to minimize DC offset. This circuit also provides 20 dB of gain to the signal. However, there are two internal mini-link jumpers that can be changed to reduce the gain at the unbalanced output to 0dB (see instructions ofor changing the unbalanced gain on page 12)
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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by Dreamer » Fri Apr 11, 2008 1:15 pm

DaveS wrote:This is right from the owner`s manual:

Balanced Output
These provide a true balanceoutput which can be connected to the balanced input jacks of a power amplifier. There is no gain from the balanced or unbalanced inputs to balanced output, only attenuation that is determined by the amount indicated on the front panel.

"No gain, only attenuation"?... Hmmmm....

So if he's getting really low output to his amp using the balanced outs, that means that his source is also pushing a realtively low-level signal. I know there is really no standard when it comes to output signals for CD players, DVD players, etc. Also, if your CDP has "fixed" and "variable" outputs, check to be sure you've got your CDP hooked up to the pre using it's "fixed" outputs. If you like the sound of the "variable" outputs, make sure the CDP's output is turned all the way up...

Perhaps he needs to get some sort of buffer amp to put between the pre and the amp, or his CD player and the pre to bring this signal up to a "proper" level?

Musical Fidelity's X10-v3 is a fantastic unit, and it's made with typical British attention to detail. And there are dozens of "pro" model buffer amps out there, some better, some not so good, that can be had cheap if you buy used.

Just a thought...

--Richard
.....HT Rig • Sony STR-DG600 Receiver • Carver M-500t • Sony BDP-S1 • Sony DVP-NS3100ES • Apple Airport Express •
..............................• Martin Logan Scenarios, Logos • Realistic Minimus 7's • Velodyne F-1500b •

2 Ch. Rig • Carver C-4000t • Silver 7t's • Krell KAV-300i • Oppo DV-981HD • Benchmark DAC1-USB • MacBook Pro 17", iTunes •
......• Technics SL-1350 turntable with Sumiko headshell, leads, and Bluepoint cartridge • Martin Logan Sequels •

.........................................................-+-Click Here to see my system-+-

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by whell » Fri Apr 11, 2008 3:32 pm

Dreamer wrote: Perhaps he needs to get some sort of buffer amp to put between the pre and the amp, or his CD player and the pre to bring this signal up to a "proper" level?

Musical Fidelity's X10-v3 is a fantastic unit, and it's made with typical British attention to detail. And there are dozens of "pro" model buffer amps out there, some better, some not so good, that can be had cheap if you buy used.

Just a thought...

--Richard
Does the Musical Fidelity unit actually bump up the gain? I thought it just "tubified" (if that's even close to being a word) the output signal.

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by Dreamer » Fri Apr 11, 2008 4:02 pm

Did I see somewhere that you are using a Carver SDA-490t CD player? Again, be sure that you are using either the "fixed" outputs, or you have the volume turned up if you're using the "variable" outputs. That CD player has pretty decent voltage on it's outputs, and SHOULD sound just fine, even with the "no gain, attentuation only" balanced outputs of the Lightstar....

Also, check your cables (that they are properly seated on the plugs) and you may want to get your tubes in the 490t tested. If they are the original tubes, they might need replaced. A lot of people have said they don't like the sound of the OEM tubes, and that they sometimes have low-volume outputs compared to newer, better-quality tubes.

--Richard
.....HT Rig • Sony STR-DG600 Receiver • Carver M-500t • Sony BDP-S1 • Sony DVP-NS3100ES • Apple Airport Express •
..............................• Martin Logan Scenarios, Logos • Realistic Minimus 7's • Velodyne F-1500b •

2 Ch. Rig • Carver C-4000t • Silver 7t's • Krell KAV-300i • Oppo DV-981HD • Benchmark DAC1-USB • MacBook Pro 17", iTunes •
......• Technics SL-1350 turntable with Sumiko headshell, leads, and Bluepoint cartridge • Martin Logan Sequels •

.........................................................-+-Click Here to see my system-+-

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by Toy Maker » Fri Apr 11, 2008 4:07 pm

Have they always been low... or is this something new ?

Do you have any other XLR sources hooked up the the preamp? if not try something else, and see the it's the preamp input, or the CD output.
Also, try a different set of inputs, I think there are 3-4 sets of XLR's

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by whell » Fri Apr 11, 2008 8:19 pm

Dreamer wrote:Did I see somewhere that you are using a Carver SDA-490t CD player?

--Richard
No, its a Sony SACD/CD player.

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by whell » Fri Apr 11, 2008 8:21 pm

Toy Maker wrote:Have they always been low... or is this something new ?

Do you have any other XLR sources hooked up the the preamp? if not try something else, and see the it's the preamp input, or the CD output.
Also, try a different set of inputs, I think there are 3-4 sets of XLR's
The output is low on the balanced outputs whether the sources are connected to the XLR or the balanced inputs. I have 3 sources connected to the XLR inputs, and two connected to the unbalanced inputs.

Thanks again for everyones input on this!

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by Toy Maker » Fri Apr 11, 2008 10:14 pm

PM sent :-$

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Re: Lightstar Direct XLR Outputs - Low Gain?

Post by BillD » Sat Apr 12, 2008 12:18 am

Am I missing something here?
DaveS wrote:Unbalanced Output

The balanced signal inside the Lightstar Direct is converted to a unbalanced output by a precision instrumentation amplifier with a DC servo circuit to minimize DC offset. This circuit also provides 20 dB of gain to the signal. However, there are two internal mini-link jumpers that can be changed to reduce the gain at the unbalanced output to 0dB (see instructions for changing the unbalanced gain on page 12)
Seems to me that this answers it all. The unbalanced is 20 dB up from balanced (that's over 3 times louder in watts, folks). TO make them equal, those mini-link jumpers need to be changed (probably described on page 12 of the manual).
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