AudioAficionado.org  

Go Back   AudioAficionado.org > Manufacturers Forums > JL Audio

JL Audio Ahead of the Curve

Reply
 
Thread Tools Display Modes
  #1  
Old 01-04-2018, 12:36 AM
Pampero Pampero is offline
Guest
 
Join Date: Mar 2016
Location: Nashville, TN.
Posts: 548
Default Insertion Loss with CR1?

I recently recalibrated/re-tuned my system and discovered about 4dB of insertion loss between my C52 preamp, CR1 X-over and my MC452 power amp. I'd been vaguely aware of it from the last tuning I did, but in retuning my rig I decided to try and set up the whole system to achieve unity gain. To do that, I used the main/sub balance controls as I couldn't think of another way to make up the gain from the CR1's output.

BTW, I am connected using balanced cables between all the components. Anybody else find this to be the case....that is that they had to do some make up in the crossover to obtain unity gain through their system?
Reply With Quote
  #2  
Old 01-05-2018, 03:27 PM
crwilli's Avatar
crwilli crwilli is online now
Racing Hoopties

 
Join Date: Feb 2013
Location: Bluffton SC
Posts: 9,768
Default

I just received a CR-1 and am reading the manual.

Have done all the easy things again?

- Recheck connections and all switches on the CR-1?
__________________
Main Equipment: Kharma Elegance dB11-S, JL Audio F113v2 X 2, Block Audio Line & Mono SE Amplification, Bricasti M21 DAC, Antipodes Kala K-50 Server
Power: Shunyata Everest 8000, Sigma XC v2, Sigma NR v2, Block Audio PCs, Defender, ADDPowr Wizard
Grounding: Shunyata Altaira CGS - 4 X Alpha CGS cables,
Network : Supra Cat 8+, Twin (Nenon) Modified Buffalo GS2016 Switches, Keces P3 LPSU,
Cables: Wireworld Platinum 8 USB, Wireworld Platinum Eclipse 8 Speaker cables, 6M & 1M Tubulus Concentus ICs,
Other: Multiple GIK products, Stillpoint Apertures, Stillpoint Minis and Ultra SS, Three 20 Amp lines, Furutech GTX - Gold outlets, Adona Rack
Reply With Quote
  #3  
Old 01-07-2018, 02:28 PM
Pampero Pampero is offline
Guest
 
Join Date: Mar 2016
Location: Nashville, TN.
Posts: 548
Default

Yeah, did that. 4dB makeup gain required input to output. Easy to see because MC gives you meters on the preamp and amp. If you get the same (unity) gain through yours, let me know. I suppose it could be there's an internal trim pot that is miscalibrated or needs to be set for my rig (more a question than statement). There's no obvious place to adjust gain externally so maybe there's some way to trim it inside, but I ain't goin' in there! Maybe I should call them.

Last edited by Pampero; 01-07-2018 at 02:34 PM.
Reply With Quote
  #4  
Old 01-07-2018, 02:46 PM
crwilli's Avatar
crwilli crwilli is online now
Racing Hoopties

 
Join Date: Feb 2013
Location: Bluffton SC
Posts: 9,768
Default

While I know what unity gain is, I am not at all clear how you ‘see’ that you don’t have it.

Can you tell me more about how you are measuring your ‘volts in and volts out’?
__________________
Main Equipment: Kharma Elegance dB11-S, JL Audio F113v2 X 2, Block Audio Line & Mono SE Amplification, Bricasti M21 DAC, Antipodes Kala K-50 Server
Power: Shunyata Everest 8000, Sigma XC v2, Sigma NR v2, Block Audio PCs, Defender, ADDPowr Wizard
Grounding: Shunyata Altaira CGS - 4 X Alpha CGS cables,
Network : Supra Cat 8+, Twin (Nenon) Modified Buffalo GS2016 Switches, Keces P3 LPSU,
Cables: Wireworld Platinum 8 USB, Wireworld Platinum Eclipse 8 Speaker cables, 6M & 1M Tubulus Concentus ICs,
Other: Multiple GIK products, Stillpoint Apertures, Stillpoint Minis and Ultra SS, Three 20 Amp lines, Furutech GTX - Gold outlets, Adona Rack
Reply With Quote
  #5  
Old 01-07-2018, 04:07 PM
Pampero Pampero is offline
Guest
 
Join Date: Mar 2016
Location: Nashville, TN.
Posts: 548
Default

Simple. Don't need a voltmeter if you have VU meters.

so:

If a system is set for unity gain throughput, any place you measure it (from the first meter's reading to the last meter's reading) should be the same. Unity gain examples: 0dBu in 0dBu out or -10 dB in, -10 out, +4 in, +4 out. Insertion loss can be measured in dBu (displayed on the meter) as well as dBv (references voltage). On either scale, the readings need to match for good gain structure.

If I feed a 1K signal into my preamp and set the preamp to output a level of -10dB(u, as I'm taking it off the meter), I should read -10dBu on the power amp's meter if I have my gain structured for unity. That's the result I get when the CR1 is not inserted in the circuit. However, when doing the the same thing with the CR1 inserted, (even before employing the filters) I read about 4dB less at the power amp.

I'm losing 4dB when the crossover is inserted in the system. 4dB insertion loss. Measured as dBu.

dBv, dBu, etc.

Last edited by Pampero; 01-07-2018 at 04:12 PM.
Reply With Quote
  #6  
Old 01-07-2018, 04:25 PM
crwilli's Avatar
crwilli crwilli is online now
Racing Hoopties

 
Join Date: Feb 2013
Location: Bluffton SC
Posts: 9,768
Default Insertion Loss with CR1?

What happens if you set the xovers to 30 and set the sub/sat balance to all sat? Does it ‘recover’? Eg, keep the cr1 inline but have all/most of the signal go to your MC452 and fronts.

I don’t want to screw with my hard-to-find settings or I would try it.
__________________
Main Equipment: Kharma Elegance dB11-S, JL Audio F113v2 X 2, Block Audio Line & Mono SE Amplification, Bricasti M21 DAC, Antipodes Kala K-50 Server
Power: Shunyata Everest 8000, Sigma XC v2, Sigma NR v2, Block Audio PCs, Defender, ADDPowr Wizard
Grounding: Shunyata Altaira CGS - 4 X Alpha CGS cables,
Network : Supra Cat 8+, Twin (Nenon) Modified Buffalo GS2016 Switches, Keces P3 LPSU,
Cables: Wireworld Platinum 8 USB, Wireworld Platinum Eclipse 8 Speaker cables, 6M & 1M Tubulus Concentus ICs,
Other: Multiple GIK products, Stillpoint Apertures, Stillpoint Minis and Ultra SS, Three 20 Amp lines, Furutech GTX - Gold outlets, Adona Rack
Reply With Quote
  #7  
Old 01-07-2018, 05:45 PM
crwilli's Avatar
crwilli crwilli is online now
Racing Hoopties

 
Join Date: Feb 2013
Location: Bluffton SC
Posts: 9,768
Default

Here are pics of my C2300 PreAmp and one MC2301 Amp playing a 1KHz signal.

From this, it appears I am gaining about 4dB...?

IMG_0544.jpg

IMG_0545.jpg
__________________
Main Equipment: Kharma Elegance dB11-S, JL Audio F113v2 X 2, Block Audio Line & Mono SE Amplification, Bricasti M21 DAC, Antipodes Kala K-50 Server
Power: Shunyata Everest 8000, Sigma XC v2, Sigma NR v2, Block Audio PCs, Defender, ADDPowr Wizard
Grounding: Shunyata Altaira CGS - 4 X Alpha CGS cables,
Network : Supra Cat 8+, Twin (Nenon) Modified Buffalo GS2016 Switches, Keces P3 LPSU,
Cables: Wireworld Platinum 8 USB, Wireworld Platinum Eclipse 8 Speaker cables, 6M & 1M Tubulus Concentus ICs,
Other: Multiple GIK products, Stillpoint Apertures, Stillpoint Minis and Ultra SS, Three 20 Amp lines, Furutech GTX - Gold outlets, Adona Rack
Reply With Quote
  #8  
Old 01-07-2018, 09:20 PM
Pampero Pampero is offline
Guest
 
Join Date: Mar 2016
Location: Nashville, TN.
Posts: 548
Default

Quote:
Originally Posted by crwilli View Post
What happens if you set the xovers to 30 and set the sub/sat balance to all sat? Does it ‘recover’? Eg, keep the cr1 inline but have all/most of the signal go to your MC452 and fronts.

I don’t want to screw with my hard-to-find settings or I would try it.
My setup, that is level matching and phase alignment are done just as you did yours if you tuned phase to the null using Ober's approach. To achieve unity gain (for best S/N, headroom and for everything to clip at the same time) I have to add an apparent 4 dB of gain (as measured by the amp's VU meter). As you'll understand since you have one, I do this via the sub/sat level control. Once I've achieved unity gain, I just go ahead and do the level and phase adjustments the same way you do.

I ended up settling on 110Hz (at least temporarily) as my crossover point as well, although I'm going to experiment some more with that. I've gotten pretty fast at getting it dialed in. It takes more time too reverse polarity and power down the alternate side than it does for me to find the null by setting level and phase so I'm not afraid of playing around. The only real issue is when to run tone (Barry's CD)....my wife hates it! .

I was just wondering if anybody else had found this issue or if it's unique to my rig. To be honest, the noise floor hasn't been audibly disturbed by this so as a practical matter it's not a big deal but it has puzzled me as I'd assume the CR1 wouldn't have a noticeable insertion loss (or as in your case, gain). And maybe it shouldn't. It's puzzling.

Last edited by Pampero; 01-07-2018 at 09:34 PM.
Reply With Quote
  #9  
Old 01-07-2018, 09:26 PM
Pampero Pampero is offline
Guest
 
Join Date: Mar 2016
Location: Nashville, TN.
Posts: 548
Default

Quote:
Originally Posted by crwilli View Post
Here are pics of my C2300 PreAmp and one MC2301 Amp playing a 1KHz signal.

From this, it appears I am gaining about 4dB...?

Attachment 53416

Attachment 53417
Isn't that strange? .

What is going on? Just as odd.....I have to add gain, you'd have to back it down 5dB or so, we're both using Macs that are well matched for gain on their lonesome.

Maybe I'm not crazy after all but I'll call them and see what gives. I suspect they'll say "don't worry: they all do that!" I will report back.

Added...I should mention that to get the actual reading (if you've got the filters set and operating), you'd want to measure at the Xover frequency. It's A LOT easier to just bypass the filters in the crossover though. In theory, gain should be the same on both legs of the crossover at the center frequency. It might be easier to just use broadband noise rather than a sine wave. Set meters to slow if you have the ability, (which the 452 does give me) should you want to measure gain with the filters active. But I think it's easier to bypass the filters for this measurement. Make sense?

Last edited by Pampero; 01-07-2018 at 09:51 PM.
Reply With Quote
  #10  
Old 01-07-2018, 09:58 PM
crwilli's Avatar
crwilli crwilli is online now
Racing Hoopties

 
Join Date: Feb 2013
Location: Bluffton SC
Posts: 9,768
Default

My quick test was done with the CR-1 on and all my settings active.

If I can use the CR-1 bypass button, I will try again tomorrow.
__________________
Main Equipment: Kharma Elegance dB11-S, JL Audio F113v2 X 2, Block Audio Line & Mono SE Amplification, Bricasti M21 DAC, Antipodes Kala K-50 Server
Power: Shunyata Everest 8000, Sigma XC v2, Sigma NR v2, Block Audio PCs, Defender, ADDPowr Wizard
Grounding: Shunyata Altaira CGS - 4 X Alpha CGS cables,
Network : Supra Cat 8+, Twin (Nenon) Modified Buffalo GS2016 Switches, Keces P3 LPSU,
Cables: Wireworld Platinum 8 USB, Wireworld Platinum Eclipse 8 Speaker cables, 6M & 1M Tubulus Concentus ICs,
Other: Multiple GIK products, Stillpoint Apertures, Stillpoint Minis and Ultra SS, Three 20 Amp lines, Furutech GTX - Gold outlets, Adona Rack
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Audioaficionado.org tested by Norton Internet Security

All times are GMT -4. The time now is 08:00 AM.



Powered by vBulletin® Version 3.8.10
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
©Copyright 2009-2023 AudioAficionado.org.Privately owned, All Rights Reserved.
Audio Aficionado Sponsors
AudioAficionado Subscriber
AudioAficionado Subscriber
Inspire By Dennis Had
Inspire By Dennis Had
Harmonic Resolution Systems
Harmonic Resolution Systems
Wyred4Sound
Wyred4Sound
Dragonfire Acoustics
Dragonfire Acoustics
GIK Acoustics
GIK Acoustics
Esoteric
Esoteric
AC Infinity
AC Infinity
JL Audio
JL Audio
Add Powr
Add Powr
Accuphase - Soulution
Accuphase - Soulution
Audio by E
Audio by E
Canton
Canton
Bryston
Bryston
WireWorld Cables
WireWorld Cables
Stillpoints
Stillpoints
Bricasti Design
Bricasti Design
Furutech
Furutech
Shunyata Research
Shunyata Research
Legend Audio & Video
Legend Audio & Video