Amplifier THD help
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Amplifier THD help
OK, looking at a few different amps, but the THD ratings are wiggin me out.
From the old days I recall that the THD should be less than 1%, is this still the way it is? I notice tha tthe Eclispe is at .05%, and even amps like Jensen (which I always thought was cheap/dirty signals) are .08%
Has the THD become less of a factor?
BTW, my last system cost $3000 back in 1995, it was all Eclipse head unit and amps, with MB Quart sepearates, Alpine speakers and sub in my seeet and awesome 1993 Gran MArquis, RIP
I am looking at these amps, preferabbvly I would like to have at least 70-75W X 4. Are these OK amps?
Phoenix Gold Octane-R 8.0:4 125W x 4 (4 ohm stereo)
Phoenix Gold Octane-R 5.0:4 80W x 4 (4 ohm)
Eclipse EA4000 4/3/2Ch Power Amplifier NEW 2005 = .05%THD
Alpine MRP-F450 70 watts RMS x 4 at 4 ohms
PPI DCX 600.4 DCX 4 CHANNEL 75Wx4 (.08% THD )
From the old days I recall that the THD should be less than 1%, is this still the way it is? I notice tha tthe Eclispe is at .05%, and even amps like Jensen (which I always thought was cheap/dirty signals) are .08%
Has the THD become less of a factor?
BTW, my last system cost $3000 back in 1995, it was all Eclipse head unit and amps, with MB Quart sepearates, Alpine speakers and sub in my seeet and awesome 1993 Gran MArquis, RIP
I am looking at these amps, preferabbvly I would like to have at least 70-75W X 4. Are these OK amps?
Phoenix Gold Octane-R 8.0:4 125W x 4 (4 ohm stereo)
Phoenix Gold Octane-R 5.0:4 80W x 4 (4 ohm)
Eclipse EA4000 4/3/2Ch Power Amplifier NEW 2005 = .05%THD
Alpine MRP-F450 70 watts RMS x 4 at 4 ohms
PPI DCX 600.4 DCX 4 CHANNEL 75Wx4 (.08% THD )
Last edited by LD85; Feb 15, 2006 at 08:42 AM.
Race Director
Joined: May 2003
Posts: 14,134
Likes: 2,979
From: Iowa
St. Jude Donor '03 thru '26
This is easy.
Here is what I look for in an amp specs.
I want it to be rated at 12 (or 12.5) volts, a THD of less than .1, and from 20Hz to 20khz.
For one, it is just about impossible to get 14.4 volts to the back of a car.
The human ear car detect distortion near the 1% level (except at bass frequencies (can have up to 10%
)
Finally, who listens to a 1 kHz tone.
So, any amp who rates their amps at 14.4 volts, 1%THD, and at 1 kHz are inflating their wattage numbers
Here is what I look for in an amp specs.
I want it to be rated at 12 (or 12.5) volts, a THD of less than .1, and from 20Hz to 20khz.
For one, it is just about impossible to get 14.4 volts to the back of a car.
The human ear car detect distortion near the 1% level (except at bass frequencies (can have up to 10%
)Finally, who listens to a 1 kHz tone.
So, any amp who rates their amps at 14.4 volts, 1%THD, and at 1 kHz are inflating their wattage numbers
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Originally Posted by knewblewkorvette
This is easy.
Here is what I look for in an amp specs.
I want it to be rated at 12 (or 12.5) volts, a THD of less than .1, and from 20Hz to 20khz.
For one, it is just about impossible to get 14.4 volts to the back of a car.
The human ear car detect distortion near the 1% level (except at bass frequencies (can have up to 10% )
Finally, who listens to a 1 kHz tone.
So, any amp who rates their amps at 14.4 volts, 1%THD, and at 1 kHz are inflating their wattage numbers
Here is what I look for in an amp specs.
I want it to be rated at 12 (or 12.5) volts, a THD of less than .1, and from 20Hz to 20khz.
For one, it is just about impossible to get 14.4 volts to the back of a car.
The human ear car detect distortion near the 1% level (except at bass frequencies (can have up to 10%
)Finally, who listens to a 1 kHz tone.
So, any amp who rates their amps at 14.4 volts, 1%THD, and at 1 kHz are inflating their wattage numbers
Many thanks, right now I am leaning toward the PPI and Eclipse, I have had a couple of Eclipse amps in the past, back when they were pricey, very clean power back then!
Le Mans Master
Joined: Aug 2005
Posts: 7,201
Likes: 0
From: DP(oh you know where) IL
St. Jude Donor '06
I just bought a octane r 8.0:4 for my dual 10" subs. Pretty good amp from what can tell. Also contact pentavolvo, he helped me get my amp in working order cause i was just lost with all the setting and what not 
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
This seems pretty cheap for a decent amp, is something wrong
http://cgi.ebay.com/Phoenix-Gold-Oct...QQcmdZViewItem
http://cgi.ebay.com/Phoenix-Gold-Oct...QQcmdZViewItem
Race Director
Joined: May 2003
Posts: 14,134
Likes: 2,979
From: Iowa
St. Jude Donor '03 thru '26
other than the fact they are lying about the wattage....
http://www.cardomain.com/item/PHOR504
and the 50X4 is at 14.4 at 14.4 volts (about 42 watts at 12 volts)
What speakers (brand and model) would this amp be for?
http://www.cardomain.com/item/PHOR504
and the 50X4 is at 14.4 at 14.4 volts (about 42 watts at 12 volts)
What speakers (brand and model) would this amp be for?
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Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
I noticed that the wattage was different on certain web sites, I wondered if maybe it was a older model etc.
My speakers are older and will get updated after I get the new receiver and sound deadening and amps put in. They are not causing any issues to date.
To be honest I dont recall what they are but I do know that they are all Infinfity Kappa speakers, I bought them @ 1997 so they are due for replacement.
The rear are 693I and the fronts are 6.5" Infinity Kappa Triaxials were bought @ 2002,
Here is another link that says 125wx4 but really, I think is 75wx4
http://www.cbrstereo.com/index.asp?P...ROD&ProdID=488
My speakers are older and will get updated after I get the new receiver and sound deadening and amps put in. They are not causing any issues to date.
To be honest I dont recall what they are but I do know that they are all Infinfity Kappa speakers, I bought them @ 1997 so they are due for replacement.
The rear are 693I and the fronts are 6.5" Infinity Kappa Triaxials were bought @ 2002,
Here is another link that says 125wx4 but really, I think is 75wx4
http://www.cbrstereo.com/index.asp?P...ROD&ProdID=488
Last edited by LD85; Feb 15, 2006 at 04:32 PM.
Le Mans Master
Joined: Aug 2005
Posts: 7,201
Likes: 0
From: DP(oh you know where) IL
St. Jude Donor '06
Originally Posted by LD85
I noticed that the wattage was different on certain web sites, I wondered if maybe it was a older model etc.
My speakers are older and will get updated after I get the new receiver and sound deadening and amps put in. They are not causing any issues to date.
To be honest I dont recall what they are but I do know that they are all Infinfity Kappa speakers, I bought them @ 1997 so they are due for replacement.
The rear are 693I and the fronts are 6.5" Infinity Kappa Triaxials were bought @ 2002,
Here is another link that says 125wx4 but really, I think is 75wx4
http://www.cbrstereo.com/index.asp?P...ROD&ProdID=488
My speakers are older and will get updated after I get the new receiver and sound deadening and amps put in. They are not causing any issues to date.
To be honest I dont recall what they are but I do know that they are all Infinfity Kappa speakers, I bought them @ 1997 so they are due for replacement.
The rear are 693I and the fronts are 6.5" Infinity Kappa Triaxials were bought @ 2002,
Here is another link that says 125wx4 but really, I think is 75wx4
http://www.cbrstereo.com/index.asp?P...ROD&ProdID=488
thats the amp i just bought. Thats what the box says that i got it in and thats what PG website says as well, 125wx4. I am happy with it the 2 days ive had it hooked up
Le Mans Master
Joined: Nov 2004
Posts: 8,718
Likes: 20
From: Dyer IN
Cruise-In IX Veteran
There is lots of decent stuff out there that you can get without breaking the bank. The PG 8.0.4 that DPG speaks of actually does like 75X4 rms i believe or 250 bridged. I just recently used this amp in an install in a minivan with the front 2 channels running EDI6000 components and the rear channels bridged into a Phoenix Gold 12 and it worked great. I would also check out Hifonics I think they make a great budget amp as well. I would stay away from the Infinity 4channel though
Race Director
Joined: May 2003
Posts: 14,134
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From: Iowa
St. Jude Donor '03 thru '26
Originally Posted by LD85
This seems pretty cheap for a decent amp, is something wrong
http://cgi.ebay.com/Phoenix-Gold-Oct...QQcmdZViewItem
http://cgi.ebay.com/Phoenix-Gold-Oct...QQcmdZViewItem
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Originally Posted by knewblewkorvette
but this auction is for the 5.0:4 and the other is the 8.0:4
Yes, I was looking at all of the PG 4-channel amps,,, but assuming that their numbers were for 14 volt, I figured more wattage was better since the numbers were inflated a bit using the 14 volt
I still would prefer to have 75w x 4 or more so the 8.0:4 was attractive, and can be bought for @ $200 or a little less.
Le Mans Master
Joined: Aug 2005
Posts: 7,201
Likes: 0
From: DP(oh you know where) IL
St. Jude Donor '06
i think i bought mine for under 200 from an ebay store called audio savings. Let me see if i can find you the link... ok i paid $157 for mine shipped
Here is the link to their store
http://search.stores.ebay.com/AUDIOS...576208QQsofpZ0
Here is the link to their store
http://search.stores.ebay.com/AUDIOS...576208QQsofpZ0
Last edited by DPG; Feb 15, 2006 at 11:37 PM.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Originally Posted by DPG
i think i bought mine for under 200 from an ebay store called audio savings. Let me see if i can find you the link... ok i paid $157 for mine shipped
Here is the link to their store
http://search.stores.ebay.com/AUDIOS...576208QQsofpZ0
Here is the link to their store
http://search.stores.ebay.com/AUDIOS...576208QQsofpZ0
Le Mans Master
Joined: Aug 2005
Posts: 7,201
Likes: 0
From: DP(oh you know where) IL
St. Jude Donor '06
Originally Posted by LD85
Thanks!
no prob, this way you can have more money on other goodies....
Their service is pretty good, it takes em about a day to answer an email, but no biggie, and shipping was pretty fast too.
Burning Brakes
Joined: Aug 2005
Posts: 1,152
Likes: 1
From: It's Bad Ass in Black! Cape Coral, Florida
This post is about a month old. I just bought the phoenix 8.0.4 for my 85, waiting for its arrival. Does anybody have any tips that might help me out? I was planning on putting it under the pass. seat if it will fit. How do you like it?
Melting Slicks
Joined: Dec 2004
Posts: 2,394
Likes: 0
From: Bay Area CA
I have just finished an install for an amp underneath my NON power passenger seat in my 01 z06. There is a pic of it in my profile. The amp I used was only 1.5" tall. But it is also about 17" long. The width really cannot be more than about 10" either as the amp needs to fit between the seat rails as well as inside the seat adjuster mechanism and the small "hammer" that drops down when the rail slides back and forth on the track. (this is of course all C5 info).
If the amp is a bit shorter in overall length that is a good thing as the rake of the seat itself slopes quite a bit from front to back and you loose seat bottom to carpet height in a hurry. (took me two layouts/mounting boards to get it right)
Fej
If the amp is a bit shorter in overall length that is a good thing as the rake of the seat itself slopes quite a bit from front to back and you loose seat bottom to carpet height in a hurry. (took me two layouts/mounting boards to get it right)
Fej