My take on the NVX JAD 900.5 - 5 channel amp - Page 2 - Car Audio | DiyMobileAudio.com | Car Stereo Forum

Reply
 
LinkBack Thread Tools Display Modes
Old 08-28-2017   #26
DIYMA 500 Club
 
manish's Avatar
 
Member
Join Date: Mar 2008
Location: Detroit
Age: 46
Posts: 871

Thanks: 160
Thanked 13 Times in 13 Posts
Rep Power: 148 manish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enough

Send a message via Yahoo to manish

iTrader: (11)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by DeltaB View Post
Concerning Zapco's offerings, the Z-LX series amps (Class A/B) which they have spent time improving on input section to offer high SQ will certainly cost you well over a grand, and as I stated before, if you have the ability, you can do a little rework and rival SQ of offerings 10 times the original price of NVX. And while I understand that rework may be beyond the abilities of some here, it's a DIY project well worth the time. Even Zapco recognizes the sonic benefits of using ELNA SilMic II's in their platform. Make sure you don't deviate from TI's strongly recommended replacement for the TL072 with Burr-Brown OPA1642's and you'll love yourself for it.
Thank you to DeltaB. For those who are not sure what to order i have included my order sheet. Now my qty is for 2 amplifiers modifications, so just cut my qty in half for 1 amp. Now i'm searching for a shop to perform these upgrades.
Attached Files
File Type: pdf Mouser Electronics.pdf (117.3 KB, 77 views)

Infinity Kappa Perfect 900 + kappa 20MX front stage
Infinity Kappa Infinity Kappa 62.11I rear stage
2 RF T1 15" (silver cone) Sealed. 2 Pioneer PRS-d800,1 pioneer PRS-D4200f bridged, 1 Pioneer PRS-X720
manish is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Old 08-28-2017   #27
 
Member
Join Date: Jun 2013
Location: Orlando, FL
Posts: 261

Thanks: 3
Thanked 27 Times in 21 Posts
Rep Power: 77 norurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Check with theamplab.net, not sure if they are willing.
norurb is offline   Reply With Quote Quick reply to this message
The Following User Says Thank You to norurb For This Useful Post:
manish (08-28-2017)
Old 08-28-2017   #28
DIYMA 500 Club
 
Newbie
Join Date: May 2005
Location: Socal
Posts: 230

Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 176 FaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enough


iTrader: (1)



Default

Zed Audio may as well - http://www.zedaudiocorp.com/service.html
FaintReality is offline   Reply With Quote Quick reply to this message
The Following User Says Thank You to FaintReality For This Useful Post:
manish (08-28-2017)
 
Old 08-28-2017   #29
DIYMA 500 Club
 
manish's Avatar
 
Member
Join Date: Mar 2008
Location: Detroit
Age: 46
Posts: 871

Thanks: 160
Thanked 13 Times in 13 Posts
Rep Power: 148 manish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enough

Send a message via Yahoo to manish

iTrader: (11)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by norurb View Post
Check with theamplab.net, not sure if they are willing.
Thanks, I just sent them a RFQ. I will await there response.


***Update*** was quoted $75 a amp.

Infinity Kappa Perfect 900 + kappa 20MX front stage
Infinity Kappa Infinity Kappa 62.11I rear stage
2 RF T1 15" (silver cone) Sealed. 2 Pioneer PRS-d800,1 pioneer PRS-D4200f bridged, 1 Pioneer PRS-X720

Last edited by manish; 08-28-2017 at 01:01 PM..
manish is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #30
 
Member
Join Date: Jun 2013
Location: Orlando, FL
Posts: 261

Thanks: 3
Thanked 27 Times in 21 Posts
Rep Power: 77 norurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by manish View Post
Thanks, I just sent them a RFQ. I will await there response.


***Update*** was quoted $75 a amp.
Will they allow you to supply the parts?
norurb is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #31
DIYMA 500 Club
 
manish's Avatar
 
Member
Join Date: Mar 2008
Location: Detroit
Age: 46
Posts: 871

Thanks: 160
Thanked 13 Times in 13 Posts
Rep Power: 148 manish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enough

Send a message via Yahoo to manish

iTrader: (11)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Yep.

Infinity Kappa Perfect 900 + kappa 20MX front stage
Infinity Kappa Infinity Kappa 62.11I rear stage
2 RF T1 15" (silver cone) Sealed. 2 Pioneer PRS-d800,1 pioneer PRS-D4200f bridged, 1 Pioneer PRS-X720
manish is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #32
DIYMA 500 Club
 
manish's Avatar
 
Member
Join Date: Mar 2008
Location: Detroit
Age: 46
Posts: 871

Thanks: 160
Thanked 13 Times in 13 Posts
Rep Power: 148 manish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enough

Send a message via Yahoo to manish

iTrader: (11)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

"Eric,

I assume you've done your research to confirm this will indeed work.
I believe $75 per amp seems appropriate for this amount of work. If this works for you, let me know and we can move forward.
Thank you,
Ethan Poissonnier
Co-Owner - Head of Sales - Public Relations
On 8/28/2017 2:50 PM, The Amp Lab wrote:
The Amp Lab
The Amp Lab
Phone: (207) 313-6236
Fax:
Name: Eric Perry
Email: [email protected]
Subject: Amplifier
I would like to submit a RFQ for a simple amp modification. I want to have all 30 signal electrolytic caps replaced with ELNA's SILMIC II silks. And all 10 JFET op-amp TL072, replaced with the Burr-Brown OPA-1642. Basically upgrading the front stage. I will supply the components, I just want to know the labor cost.

Amp: NVX JAD 900.5
QTY: 2
Upgraded OP-amp: OPA1642AIDR
QTY: 10 per amplifier
Upgraded 10uF Cap: Aluminum Electrolytic Capacitors - Leaded 10uF 35V 20% Audio SILMIC II
QTY: 20 per amplifier
Upgraded 22uF Cap: Aluminum Electrolytic Capacitors - Leaded 22uF 35V 20% Audio SILMIC II
QTY: 10 per amplifier

---
Thank you for using our services
The Amp Lab"

Infinity Kappa Perfect 900 + kappa 20MX front stage
Infinity Kappa Infinity Kappa 62.11I rear stage
2 RF T1 15" (silver cone) Sealed. 2 Pioneer PRS-d800,1 pioneer PRS-D4200f bridged, 1 Pioneer PRS-X720
manish is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #33
 
Member
Join Date: Jun 2013
Location: Orlando, FL
Posts: 261

Thanks: 3
Thanked 27 Times in 21 Posts
Rep Power: 77 norurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Great info, thanks.
norurb is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #34
 
Member
Join Date: Jun 2017
Location: USA
Posts: 306

Thanks: 0
Thanked 49 Times in 33 Posts
Rep Power: 30 DeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by manish View Post
"Eric,

I assume you've done your research to confirm this will indeed work.
I believe $75 per amp seems appropriate for this amount of work. If this works for you, let me know and we can move forward.
Thank you,
Ethan Poissonnier
Co-Owner - Head of Sales - Public Relations
On 8/28/2017 2:50 PM, The Amp Lab wrote:
The Amp Lab
The Amp Lab
Phone: (207) 313-6236
Fax:
Name: Eric Perry
Email: [email protected]
Subject: Amplifier
I would like to submit a RFQ for a simple amp modification. I want to have all 30 signal electrolytic caps replaced with ELNA's SILMIC II silks. And all 10 JFET op-amp TL072, replaced with the Burr-Brown OPA-1642. Basically upgrading the front stage. I will supply the components, I just want to know the labor cost.

Amp: NVX JAD 900.5
QTY: 2
Upgraded OP-amp: OPA1642AIDR
QTY: 10 per amplifier
Upgraded 10uF Cap: Aluminum Electrolytic Capacitors - Leaded 10uF 35V 20% Audio SILMIC II
QTY: 20 per amplifier
Upgraded 22uF Cap: Aluminum Electrolytic Capacitors - Leaded 22uF 35V 20% Audio SILMIC II
QTY: 10 per amplifier

---
Thank you for using our services
The Amp Lab"
Just for you and Amp Lab's concern, here is something for your viewing pleasure concerning the proper selection of op amps for this modification.

https://e2e.ti.com/support/amplifier...udio-equipment
DeltaB is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #35
 
Member
Join Date: Mar 2015
Location: Cincinnati, OH
Posts: 526

Thanks: 12
Thanked 30 Times in 30 Posts
Rep Power: 59 dsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by DeltaB View Post
My system starts with a NVX JAD 900.5, which internal design and boards are shared by a number of companies, both big name, as well as private and not-so-big vendors. Upon receipt, I opened the case to examine components and solder quality, and found what is ever present in auto amps, and that is signal components, like op-amps and electrolytic caps of poor quality and inexpensive price, seriously degrading the ability of the amp to produce true high-quality sound. There is a HUGE difference between noise, and being-there type of reproduction. Loud isn't better. It's just noisy.

One of these in this amp, was the use of TI's TL072 op amps for all buffering and signal conditioning. This device, produced since the 70's was one of the first JFET op-amps widely used for high-impedance input circuits, and was quickly overshadowed by the NE5532 for audio usage. This $0.37 part is best used to control a variable speed motor, and not audio, since there are numerous selections of much better audio quality. With 18nV of noise, it produces a constant hiss that is audible in the output section. And while it's slew speed is 13V/us, which is considered tabletop radio quality, the most important factor of the TL072, is the phase shift over the audio spectrum, which changes more than 120 degrees over just a few octaves. In fact, when driven at modest voltages, it can change polarity, causing 180 degree cancellation of frequencies. (phase reversal) This is very bad for your audio, in fact, it's unacceptable. Needless to say, the bean-counters, who opted for least cost, gave it to us with no regard to what is given up in audio quality. This is indicative of all amps on the market today, even in the home audio arena. (My high-end Yamaha AVENTAGE RX-A2030 even suffered from this cost cutting oversight in using low-cost poor-performing op-amps)

So what I've done is to use TI's recommended replacement for input designs that have utilized JFET op-amps, like the TL072, using the Burr-Brown OPA-1642. This op-amp brings with it a number of really impressive performance upgrades. One, comparing it to the TL072, who's THD was 0.003%, with the new, gains me a very impressive 0.00005% total THD, with less than 1/4 of the noise. It's slew rate is almost double of that of the TL072, and gets into the 20V/us slew rate, which can handle complex audio without losing detail. It takes less current to run it, and makes a good drop in replacement without having to redesign the circuit. The real advantage to this change, comes from the most important factor, and that is phase. Your ears are incredibly sensitive to phase, and audio phase is one of the most important things in creating sinusoidal waves that sound "real". The OPA-1642 is phase stable (no shift) throughout the entire audio spectrum all the way up into the MHz range. The soundstage with the new op-amps is nothing short of incredible, and places it in a performance category with some of the finest home audio out there. Channel separation went from around 90dB of separation to almost 130dB, and CMRR went from -86dB to -128dB. Talk about now having an extremely quiet, and low distortion amp. Mono blocks don't perform better than this folks.

All of the signal electrolytic caps were replaced with ELNA's SILMIC II silks, which has become the defacto-standard of audio signal caps these days, and bring with them a very warm and inviting sound.

All of this was done with a little rework time and less than $50. Now, this $250 investment can rival performance of amps 10 times it's cost. The finest investment one can make in their car audio systems, is the attention to detail in the input section of their amplifier, and since all amps suffer this, is the first place to spend attention to really create a soundstage in your vehicle that will rival any out there. It's all about making a correctly phased and uncolored sinusoidal wave for your ear. The manufacturer's bean-counter ripped you off.

I wonder if anyone could go to a manufacturer and make a custom order with the changes that you made. Do you think a manufacturer would make those alterations (that you did) in a special order? This way, maybe someone could get that upgraded amp and keep the manufacturer's warranty...maybe.
dsw1204 is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #36
DIYMA 500 Club
 
manish's Avatar
 
Member
Join Date: Mar 2008
Location: Detroit
Age: 46
Posts: 871

Thanks: 160
Thanked 13 Times in 13 Posts
Rep Power: 148 manish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enough

Send a message via Yahoo to manish

iTrader: (11)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

No. Those Amps are made overseas and shipped here.

Infinity Kappa Perfect 900 + kappa 20MX front stage
Infinity Kappa Infinity Kappa 62.11I rear stage
2 RF T1 15" (silver cone) Sealed. 2 Pioneer PRS-d800,1 pioneer PRS-D4200f bridged, 1 Pioneer PRS-X720
manish is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #37
 
Member
Join Date: Mar 2015
Location: Cincinnati, OH
Posts: 526

Thanks: 12
Thanked 30 Times in 30 Posts
Rep Power: 59 dsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enoughdsw1204 will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by manish View Post
No. Those Amps are made overseas and shipped here.
I really wasn't expecting a positive reply, just hoping. There is one manufacturer who makes in the U.S.. MMATS, but their prices are pretty high to begin with.
dsw1204 is offline   Reply With Quote Quick reply to this message
Old 08-28-2017   #38
DIYMA 500 Club
 
Newbie
Join Date: May 2005
Location: Socal
Posts: 230

Thanks: 0
Thanked 2 Times in 2 Posts
Rep Power: 176 FaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enoughFaintReality will become famous soon enough


iTrader: (1)



Default

What is the difference between the OPA1642AIDR / AID / AIDGKR / AIDGKT?
FaintReality is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #39
 
Member
Join Date: Jun 2017
Location: USA
Posts: 306

Thanks: 0
Thanked 49 Times in 33 Posts
Rep Power: 30 DeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by FaintReality View Post
What is the difference between the OPA1642AIDR / AID / AIDGKR / AIDGKT?
Package sizes and body type. You can reference the end of datasheet to see the difference. For this amp you want AIDR or AID. GK is much smaller VSSOP package. You need SOIC-8 body.

http://www.ti.com/lit/ds/symlink/opa1642.pdf
DeltaB is offline   Reply With Quote Quick reply to this message
The Following User Says Thank You to DeltaB For This Useful Post:
manish (08-29-2017)
Old 08-29-2017   #40
DIYMA 500 Club
 
manish's Avatar
 
Member
Join Date: Mar 2008
Location: Detroit
Age: 46
Posts: 871

Thanks: 160
Thanked 13 Times in 13 Posts
Rep Power: 148 manish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enough

Send a message via Yahoo to manish

iTrader: (11)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Is there any modification you recommend with the power supply? or do you think its pretty stout as is?

Infinity Kappa Perfect 900 + kappa 20MX front stage
Infinity Kappa Infinity Kappa 62.11I rear stage
2 RF T1 15" (silver cone) Sealed. 2 Pioneer PRS-d800,1 pioneer PRS-D4200f bridged, 1 Pioneer PRS-X720
manish is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #41
DIYMA 500 Club
 
fcarpio's Avatar
 
Enthusiast
Join Date: Apr 2008
Location: South Florida
Posts: 2,893

Thanks: 21
Thanked 54 Times in 48 Posts
Rep Power: 167 fcarpio will become famous soon enoughfcarpio will become famous soon enoughfcarpio will become famous soon enoughfcarpio will become famous soon enoughfcarpio will become famous soon enoughfcarpio will become famous soon enoughfcarpio will become famous soon enough


iTrader: (12)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

This is a very cool concept, but an amp that is a great "base" for upgrading and then upgrade the parts that need to go. I wonder if this is as straight forward as it seems because there is a lot of engineering that goes into this things. Is something as simple as changing some parts will make a "positive" difference? It would also be nice if whomever is upgrading this amp could do some sort of A/B test of the before and after to see what kind of differences we are looking at.
fcarpio is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #42
Upgrade Your Membership!
 
rton20s's Avatar
 
Enthusiast
Join Date: Feb 2011
Location: Central Valley California
Posts: 8,606

Thanks: 623
Thanked 692 Times in 501 Posts
Rep Power: 356 rton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond reputerton20s has a reputation beyond repute


iTrader: (8)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by dsw1204 View Post
I wonder if anyone could go to a manufacturer and make a custom order with the changes that you made. Do you think a manufacturer would make those alterations (that you did) in a special order? This way, maybe someone could get that upgraded amp and keep the manufacturer's warranty...maybe.
Quote:
Originally Posted by manish View Post
No. Those Amps are made overseas and shipped here.
If this customization is something you are looking to do, I would follow the path that DeltaB has laid out. If you want to see it at a larger scale, your best bet is to find yourself a pile of cash, find out who the actual amplifier manufacturer is, and meet their minimum order requirements for a run of amps built to your spec. Congratulations, you're in the car audio "manupackturer" business. Good luck with that.


Pioneer DEH-80PRS | Helix DSP.2 | Zapco Z-150.6 AP + Z-400.2 AP (x2) | Illusion TL 25 BN | Illusion C5 | Raven 10XL (x2)
2015 MECA SQL Street | 2017 & 2018 MECA Modex California State Champion
Sonic Electronix Discount Code: hutsell
rton20s is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #43
DIYMA 500 Club
 
manish's Avatar
 
Member
Join Date: Mar 2008
Location: Detroit
Age: 46
Posts: 871

Thanks: 160
Thanked 13 Times in 13 Posts
Rep Power: 148 manish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enoughmanish will become famous soon enough

Send a message via Yahoo to manish

iTrader: (11)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by fcarpio View Post
This is a very cool concept, but an amp that is a great "base" for upgrading and then upgrade the parts that need to go. I wonder if this is as straight forward as it seems because there is a lot of engineering that goes into this things. Is something as simple as changing some parts will make a "positive" difference? It would also be nice if whomever is upgrading this amp could do some sort of A/B test of the before and after to see what kind of differences we are looking at.
Normally you are correct. But based on the suggested upgrades, we are using the same value components, just higher quality. So its not like we are adding caps or op-amps. Also it was already done with just the listed mods. I really think your right with a nice comparison though. I plan to do a pair of these 5 channel amps, maybe when i get to it, i can do 1 and then have someone test them or i can do a a/b swap out and provide a more real world comparison. Its been awhile since i did a review so this could be a nice project for this fall. Kinda wish Wldock = Walt was still here in Michigan to have another pair of seasoned ears.

Infinity Kappa Perfect 900 + kappa 20MX front stage
Infinity Kappa Infinity Kappa 62.11I rear stage
2 RF T1 15" (silver cone) Sealed. 2 Pioneer PRS-d800,1 pioneer PRS-D4200f bridged, 1 Pioneer PRS-X720

Last edited by manish; 08-29-2017 at 10:37 AM..
manish is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #44
 
Member
Join Date: Jun 2017
Location: USA
Posts: 306

Thanks: 0
Thanked 49 Times in 33 Posts
Rep Power: 30 DeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by fcarpio View Post
This is a very cool concept, but an amp that is a great "base" for upgrading and then upgrade the parts that need to go. I wonder if this is as straight forward as it seems because there is a lot of engineering that goes into this things. Is something as simple as changing some parts will make a "positive" difference? It would also be nice if whomever is upgrading this amp could do some sort of A/B test of the before and after to see what kind of differences we are looking at.
It isn't a concept. It is as strait forward in this case, as it has already been done. I own one. There isn't any real magic here.
DeltaB is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #45
 
Newbie
Join Date: Apr 2013
Location: broken arrow ok
Posts: 42

Thanks: 6
Thanked 7 Times in 7 Posts
Rep Power: 78 willis36 will become famous soon enoughwillis36 will become famous soon enoughwillis36 will become famous soon enoughwillis36 will become famous soon enoughwillis36 will become famous soon enoughwillis36 will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Subbed for future reference. I assume this mod will work with the PPI Phantom series??
willis36 is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #46
 
Member
Join Date: Jun 2013
Location: Orlando, FL
Posts: 261

Thanks: 3
Thanked 27 Times in 21 Posts
Rep Power: 77 norurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enoughnorurb will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by fcarpio View Post
This is a very cool concept, but an amp that is a great "base" for upgrading and then upgrade the parts that need to go. I wonder if this is as straight forward as it seems because there is a lot of engineering that goes into this things. Is something as simple as changing some parts will make a "positive" difference? It would also be nice if whomever is upgrading this amp could do some sort of A/B test of the before and after to see what kind of differences we are looking at.
A few years back I was providing a service for Nissan SR20DE/DET ecu upgrades. The upgrade involved adding a daughterboard and reflashed eproms. Concept was to take a well engineered oem part and mod it for power upgrades. Point is that oem will get you so far but mods will make it that much better.

Burson Audio has a link that demonstrates the desoldering/soldering for opamp upgrades. Nifty video.
norurb is offline   Reply With Quote Quick reply to this message
Old 08-29-2017   #47
 
Member
Join Date: Jun 2017
Location: USA
Posts: 306

Thanks: 0
Thanked 49 Times in 33 Posts
Rep Power: 30 DeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by willis36 View Post
Subbed for future reference. I assume this mod will work with the PPI Phantom series??
I don't have a schematic, so I would actually have to see the amp to comment on what buffers they are using.

Concerning the usage of signal path upgrade caps, that is universal. The reason we use coupling caps before and after the op-amp, is to isolate DC from it's input and protect it's output, and only AC passes. It's a DC block. Since all of the signal going in, and coming out of that buffer circuit through them, it is certainly applicable, and audible.

Concerning the op-amp, if it is using a TI TL072, then yes, you can do a drop in replacement with a Burr-Brown OPA1642. If you were to use SPICE data to construct a buffer with a JFET, you would find the data for gain structure the same, and since you don't have to worry about the need for feedback, like you have to deal with on some bi-polar designs, it makes an easy choice. TL072's have no place in audio circuits. They're slow, noisy, overshoot and invert phase at higher levels.
DeltaB is offline   Reply With Quote Quick reply to this message
Old 08-30-2017   #48
 
Member
Join Date: Oct 2016
Location: Tennessee
Posts: 269

Thanks: 3
Thanked 20 Times in 15 Posts
Rep Power: 37 Swaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by DC/Hertz View Post
I really want to try the ST-4SQ but I don't know about cutting my power in half. I do like it loud from time to time when the windows are down on the high way.
How much power do you need? The ST4X P version is 80x4 instead of 65x4 in the SQ version. If you are worried about mid power bridged 2 channels is more than enough. Unless you would be using this on a sub or 2 than different story.

This might be a dumb question concerning 5 channels as I've never owned one. Specs always list 4ohm and 2 ohm. Can the amp be ran at 2ohms on the sub channel and 4 ohms on the 4 other channels. I was worried about some kind of limitation when wiring this route. I always wire my subs at 1-2 ohm load
Swaglife81 is offline   Reply With Quote Quick reply to this message
Old 08-30-2017   #49
 
Member
Join Date: Jun 2017
Location: USA
Posts: 306

Thanks: 0
Thanked 49 Times in 33 Posts
Rep Power: 30 DeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enoughDeltaB will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by Swaglife81 View Post
How much power do you need? The ST4X P version is 80x4 instead of 65x4 in the SQ version. If you are worried about mid power bridged 2 channels is more than enough. Unless you would be using this on a sub or 2 than different story.

This might be a dumb question concerning 5 channels as I've never owned one. Specs always list 4ohm and 2 ohm. Can the amp be ran at 2ohms on the sub channel and 4 ohms on the 4 other channels. I was worried about some kind of limitation when wiring this route. I always wire my subs at 1-2 ohm load
While I understand that many want to run subs at 1~2ohm, for SQ it is preferable to run at least 4ohm due to damping factor and output impedance of Class D operation.

From Brian Morelli @ NVX Tech;

Minimum impedance for all channels is 2ohms. You can have different loads on different channels. (4ohm on the fronts/rear, 2ohm on sub).

The damping factor for all JADs is greater than 200

NVX Tech
DeltaB is offline   Reply With Quote Quick reply to this message
The Following User Says Thank You to DeltaB For This Useful Post:
Swaglife81 (08-30-2017)
Old 08-30-2017   #50
 
Member
Join Date: Oct 2016
Location: Tennessee
Posts: 269

Thanks: 3
Thanked 20 Times in 15 Posts
Rep Power: 37 Swaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enoughSwaglife81 will become famous soon enough


iTrader: (0)



Default Re: My take on the NVX JAD 900.5 - 5 channel amp

Quote:
Originally Posted by DeltaB View Post
While I understand that many want to run subs at 1~2ohm, for SQ it is preferable to run at least 4ohm due to damping factor and output impedance of Class D operation.

From Brian Morelli @ NVX Tech;

Minimum impedance for all channels is 2ohms. You can have different loads on different channels. (4ohm on the fronts/rear, 2ohm on sub).

The damping factor for all JADs is greater than 200

NVX Tech
Thanks, exactly what I wanted to know. It might have been the amps I used in the past but I was running a Fosgate 500x2 at 2 ohms vs 250x2 at 4 ohms but couldn't audibly hear a difference other than SPL. I understand an amp will work harder. I ran that amp for years. Aside from metering differences with various equipment seeing the difference how much difference can someone hear with 2 ohms vs 4 ohms given the same quality and power output is equal?
Swaglife81 is offline   Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Car Audio | DiyMobileAudio.com | Car Stereo Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Location
Where you live
First name
Last name
Do you work in the 12 Volt industry?
Do you work in the 12 Volt industry?
Youtube Channel
Enter Your Youtube Username, And It will Be Linked To In Your Posts!
12V Industry - Company Name
Your company name.
12V Industry - Your Position
Your position in your company.

Log-in



Currently Active Users Viewing This Thread: 3 (0 members and 3 guests)
 
Thread Tools
Display Modes

Posting Rules
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On


Powered by vBadvanced CMPS v3.2.3

All times are GMT -6. The time now is 07:24 AM.


Powered by vBulletin®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0
Powered by vBadvanced CMPS v3.2.3
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.

Ad Management by RedTyger

Home | User CP | Members List | New Posts | ITrader | Faq | Post Spy