Hi All,
I'm new to car audio amps, at least from the repair perspective, and I've read a lot about the differences in power delivery, build quality etc, between amps. Over the last couple of weeks I've repaired 9 older (1998ish) ordinary 2 channel car amps, with a few more on the way, just to get an idea about construction, ruggedness, common practices, and generally discover the differences between the good the bad and of course the ugly. To my surprise, there was little or no difference between the random selection I bought, with a few conspicuous exceptions. No class D amps here, just your regular AB models...
For your reading pleasure here's the list of what I've repaired:
Soundstream SA80
Rockford Fosgate punch 250a2
Boss audio US250
Kenwood KAC728s
Hifonics Falcon
Pioneer GMX-362
US Acoustics USX2080
Pioneer GMX952
Earthquake Power 400xO
Some of these are so similar internally I'd guess there is only one actual design house for them, the odd ones being the soundstream, pioneers and kenwood amp. The soundstream, pioneer and kenwood models have heavier aluminum extrusions, and are generally more overbuilt than the others, bigger transistors relative to power output etc. None of them were underbuilt in any obvious way except for heatsinking...
They all have mosfet DC to DC converters, about 1/3 are regulated, but only half have mosfet power amps.
They all met their power ratings, just...however, not many of them would survive very long doing so, the heatsinking provided by the extrusions is simply not adequate, the hifonics amp being the smallest and hottest by far, for comparison the SA80 is the same size with less than half the power rating, so it does much better in the heating test...
I don't really know which of these is considered 'cheap' or 'good', but if I was choosing which to use, it would probably be the soundstream, then perhaps the big pioneer or kenwood, though they are much larger...the hifonics amp provides very big bang for it's size, but it also gets very hot very fast...of course the listening test will provide the final answer, but based on my looking at the amp schematics, I don't expect any big differences here...
I'll be doing some actual listening tests later, let me know what you guys think of these amps...not sure what I'm gonna do with them once I've finished testing, but I will want to use a couple...
Stuart
I'm new to car audio amps, at least from the repair perspective, and I've read a lot about the differences in power delivery, build quality etc, between amps. Over the last couple of weeks I've repaired 9 older (1998ish) ordinary 2 channel car amps, with a few more on the way, just to get an idea about construction, ruggedness, common practices, and generally discover the differences between the good the bad and of course the ugly. To my surprise, there was little or no difference between the random selection I bought, with a few conspicuous exceptions. No class D amps here, just your regular AB models...
For your reading pleasure here's the list of what I've repaired:
Soundstream SA80
Rockford Fosgate punch 250a2
Boss audio US250
Kenwood KAC728s
Hifonics Falcon
Pioneer GMX-362
US Acoustics USX2080
Pioneer GMX952
Earthquake Power 400xO
Some of these are so similar internally I'd guess there is only one actual design house for them, the odd ones being the soundstream, pioneers and kenwood amp. The soundstream, pioneer and kenwood models have heavier aluminum extrusions, and are generally more overbuilt than the others, bigger transistors relative to power output etc. None of them were underbuilt in any obvious way except for heatsinking...
They all have mosfet DC to DC converters, about 1/3 are regulated, but only half have mosfet power amps.
They all met their power ratings, just...however, not many of them would survive very long doing so, the heatsinking provided by the extrusions is simply not adequate, the hifonics amp being the smallest and hottest by far, for comparison the SA80 is the same size with less than half the power rating, so it does much better in the heating test...
I don't really know which of these is considered 'cheap' or 'good', but if I was choosing which to use, it would probably be the soundstream, then perhaps the big pioneer or kenwood, though they are much larger...the hifonics amp provides very big bang for it's size, but it also gets very hot very fast...of course the listening test will provide the final answer, but based on my looking at the amp schematics, I don't expect any big differences here...
I'll be doing some actual listening tests later, let me know what you guys think of these amps...not sure what I'm gonna do with them once I've finished testing, but I will want to use a couple...
Stuart
Well, all guys are cooking with water 🙂
The reason for beeing similar is that most amps are made in Korea or China. Nowadays this got even "worse" . I think 70% of the amps sold in Germany are made in Korea by KIA , one of the major manuf. for this stuff. No matter what brand you get, they all use the same parts and curcuits, difference in power is achieved by putting more output stages "in parallel" , or in the DC-converters most of the times there are just mor MOSFET used.
But there are still big differences in assembling quality.
The amps you got should have some differences in the DC-converters , e.g. Kenwood DC converrtes are a biz oversized, in my repair time I never had a kenwood with a DC-converter failure.
the hifonics amps usually run hotter, especially the blue "8" Series amps due to "small" heatsinks compared to the available output power.
Differences can also be found in part-quality. While nowadays the standard-transistors in the amp-section are KTD778 and KTB998 Hifonics used to install TIP35 /36C , that can handle more power . Also capacitors influence the "sound" of an Amplifier. While in "cheaper " amps regular caps are used, better amps have Low-ESR caps with higher tempoerature ratings installed. Sometimes it´s just smaller things...... that matter 🙂
The reason for beeing similar is that most amps are made in Korea or China. Nowadays this got even "worse" . I think 70% of the amps sold in Germany are made in Korea by KIA , one of the major manuf. for this stuff. No matter what brand you get, they all use the same parts and curcuits, difference in power is achieved by putting more output stages "in parallel" , or in the DC-converters most of the times there are just mor MOSFET used.
But there are still big differences in assembling quality.
The amps you got should have some differences in the DC-converters , e.g. Kenwood DC converrtes are a biz oversized, in my repair time I never had a kenwood with a DC-converter failure.
the hifonics amps usually run hotter, especially the blue "8" Series amps due to "small" heatsinks compared to the available output power.
Differences can also be found in part-quality. While nowadays the standard-transistors in the amp-section are KTD778 and KTB998 Hifonics used to install TIP35 /36C , that can handle more power . Also capacitors influence the "sound" of an Amplifier. While in "cheaper " amps regular caps are used, better amps have Low-ESR caps with higher tempoerature ratings installed. Sometimes it´s just smaller things...... that matter 🙂
Perhaps mine are not 'current' amps...
Hi,
According to the markings on the amps they were made in the USA, some clearly marked on the board as being assembled by a company call Zed audio, perhaps they also did the design, explaining the similarities.
All of these amps use irfz44 or buz11 fets in the smps, most use the tl494 control chip, some have an additional chip to provide make muting and regulation, error control etc work.
The mosfet amps all use irf parts in the output, while the bipolar amps either use tip35/36 or sanken transistors of very similar ratings, package etc.
Some of the failures were as follows:
GMX952: 1 output transistor not tight on heatsink cooked itself, shorted out.
KAC728s: power previously connected with reverse polarity, protection diode fried and shorted out.
Hifonics: dry solder joints making intermittent shutdown
SA80: Someone tried driving a dead short and destroyed one channels output and one of the smps fets.
250a2: cooked smps fet
400xO: input opamps killed, presumably by high level signal on low level input.
GMX362: capacitor exploded internally, ultimately shorted and shut smps down
BA US250: loose input RCA
So since they are all working again, which do you think are the 'best'?
Stuart
Hi,
According to the markings on the amps they were made in the USA, some clearly marked on the board as being assembled by a company call Zed audio, perhaps they also did the design, explaining the similarities.
All of these amps use irfz44 or buz11 fets in the smps, most use the tl494 control chip, some have an additional chip to provide make muting and regulation, error control etc work.
The mosfet amps all use irf parts in the output, while the bipolar amps either use tip35/36 or sanken transistors of very similar ratings, package etc.
Some of the failures were as follows:
GMX952: 1 output transistor not tight on heatsink cooked itself, shorted out.
KAC728s: power previously connected with reverse polarity, protection diode fried and shorted out.
Hifonics: dry solder joints making intermittent shutdown
SA80: Someone tried driving a dead short and destroyed one channels output and one of the smps fets.
250a2: cooked smps fet
400xO: input opamps killed, presumably by high level signal on low level input.
GMX362: capacitor exploded internally, ultimately shorted and shut smps down
BA US250: loose input RCA
So since they are all working again, which do you think are the 'best'?
Stuart
Hi
Probably the Hifonics and the SS are "ZED" amps, , maybe Stephen Mantz had his fingers involved here. he is one of the pioneers in Audio- Amplifiers . Probably the TED-amps are "the best" , but how would you want to consider " best" and how to compare.
regulated DC-converters usually make more power possible , but there are a few old Korea-Amps around that have fixed Dc-converters and still deliver enourmous power and stability.
Personaly I like American made amplifiers the most. Most American amps deliver unsophisticated sound and power, manuf. quality is very good in most cases compared to todays Asia-amps. Again personally I dont "demand" to much on car amplifiers but I like when the amp is capable of producing clean sound at higher levels, and standard amps like the kenwood or the pioneer are good for general purpose.
but I think all amplifiers you have got some or their quality , you should see amplifiers around here, it´s a big market in germany and everyone wants to make big money. I´ve seen so much trash "wrapped" inside nice heatsinks . But I also have seen very good products from socalled "cheap producers" .
As always, mans own opinion decide wheather its a good or a bad Amp.
Probably the Hifonics and the SS are "ZED" amps, , maybe Stephen Mantz had his fingers involved here. he is one of the pioneers in Audio- Amplifiers . Probably the TED-amps are "the best" , but how would you want to consider " best" and how to compare.
regulated DC-converters usually make more power possible , but there are a few old Korea-Amps around that have fixed Dc-converters and still deliver enourmous power and stability.
Personaly I like American made amplifiers the most. Most American amps deliver unsophisticated sound and power, manuf. quality is very good in most cases compared to todays Asia-amps. Again personally I dont "demand" to much on car amplifiers but I like when the amp is capable of producing clean sound at higher levels, and standard amps like the kenwood or the pioneer are good for general purpose.
but I think all amplifiers you have got some or their quality , you should see amplifiers around here, it´s a big market in germany and everyone wants to make big money. I´ve seen so much trash "wrapped" inside nice heatsinks . But I also have seen very good products from socalled "cheap producers" .
As always, mans own opinion decide wheather its a good or a bad Amp.
best, what does it mean?
Doom, thanks for your input, I tried finding Zed audio on the web, there are a few mentions of the company, but they don't seem to have any website of their own. I have managed to get schematics for most of these amps, and in most cases I didnt need them, but when things need adjusting it's nice to know approx. settings and voltages.
With respect to best, in this case, for me, it means the sound quality. Since these guys are all supposed to be able to drive 2ohms, they are all going to get a bit of a workout, I have a pair of Apogee Duetta's Signatures, by repute a tough load for any amp, let the best/surviving amp win...I have a transformer from a heavy duty battery charger, rated about 35-40 amps continuous, I plan on using it in parallel with a couple of 12v/7ah UPS batteries, and 0.25F, made from parallel caps, a real 0.25F cap...
Should be good for a few sparks if nothing else...
When I'm done I think I'll offer the survivors in the trading post, basically at cost, there are probably people here who'd like them.
Stuart
Doom, thanks for your input, I tried finding Zed audio on the web, there are a few mentions of the company, but they don't seem to have any website of their own. I have managed to get schematics for most of these amps, and in most cases I didnt need them, but when things need adjusting it's nice to know approx. settings and voltages.
With respect to best, in this case, for me, it means the sound quality. Since these guys are all supposed to be able to drive 2ohms, they are all going to get a bit of a workout, I have a pair of Apogee Duetta's Signatures, by repute a tough load for any amp, let the best/surviving amp win...I have a transformer from a heavy duty battery charger, rated about 35-40 amps continuous, I plan on using it in parallel with a couple of 12v/7ah UPS batteries, and 0.25F, made from parallel caps, a real 0.25F cap...
Should be good for a few sparks if nothing else...
When I'm done I think I'll offer the survivors in the trading post, basically at cost, there are probably people here who'd like them.
Stuart
Hi
sorry, my English is not any good.....anymore. I was lucky and spent 1 year in Oregon and went to Highschool there. Fun time ! 🙂
)Also I didn´t mean Ted, I meant Zed )
Here is some information on Stephen Mantz , he designed some of the toughest and "best" 🙂 amplifiers on the market, including the Series8 of Hifonics, still one of my favorites amplifier series.
Stephen mantz / ZED Audio
I think alll your mentioned amps can be used and they all can deliver good results if they are used for what they´ve been made for, meaning you dont have any trash there.
These are pictures of an amplifier I fixed last week...... stated 1600W of power......
I was really surprised that nowadays things like that are beeing sold. I think this is fraud.
There is no SMPS. They used 2 power IC from Toshiba, capable of delivering 4x20W RMS into 4 Ohms at max. power supply (16VDC). Thats real garbage ! Those Toshiba IC are sometimes used in cheap Car stereos (I mean the headunit´s installed amplifiers) ....... But the dealers make tons of money with the amplifier shown in the pics. Usually it goes for 60 to70 US Dollars in ebay.
Hope anybody can understand what I´m trying to tell 🙂
sorry, my English is not any good.....anymore. I was lucky and spent 1 year in Oregon and went to Highschool there. Fun time ! 🙂
)Also I didn´t mean Ted, I meant Zed )
Here is some information on Stephen Mantz , he designed some of the toughest and "best" 🙂 amplifiers on the market, including the Series8 of Hifonics, still one of my favorites amplifier series.
Stephen mantz / ZED Audio
I think alll your mentioned amps can be used and they all can deliver good results if they are used for what they´ve been made for, meaning you dont have any trash there.
These are pictures of an amplifier I fixed last week...... stated 1600W of power......
I was really surprised that nowadays things like that are beeing sold. I think this is fraud.An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
There is no SMPS. They used 2 power IC from Toshiba, capable of delivering 4x20W RMS into 4 Ohms at max. power supply (16VDC). Thats real garbage ! Those Toshiba IC are sometimes used in cheap Car stereos (I mean the headunit´s installed amplifiers) ....... But the dealers make tons of money with the amplifier shown in the pics. Usually it goes for 60 to70 US Dollars in ebay.
Hope anybody can understand what I´m trying to tell 🙂
oh my god...
Doom,
Your english is fine, and infinitely better than my german...
I have never seen anything like it, I was assumed I'd got the worst the car audio industry could offer through buying only dead units, but boy did I luck out. You should publish your pictures in a new thread so people have a better understanding of just how bad these things can get...does that unit have a brand name I might recognise?
Really I bet most people buying these things don't understand how badly they are being ripped off.
Stuart
Doom,
Your english is fine, and infinitely better than my german...
I have never seen anything like it, I was assumed I'd got the worst the car audio industry could offer through buying only dead units, but boy did I luck out. You should publish your pictures in a new thread so people have a better understanding of just how bad these things can get...does that unit have a brand name I might recognise?
Really I bet most people buying these things don't understand how badly they are being ripped off.
Stuart
Zed hasn`t had anything to do with hifonics since the 7 or 8 series,and most of ones they did were name after greek gods(their slogan was power of the gods) so the Falcon is most likely designed by someone else.there were and still big corporate buy out,it`s sad.
As doom said they were small heatsinks on most of the ones that they had done.As for the others I`m not real sure.
I think that the days of good stuff is about gone.I`ve been buy some of the `80`s and early 90`s stuff just because I think that it is much better in many ways.I`ve got a PPI that brought almost 20 years ago and use it daily and knock on wood it`s never missed a beat.And the new PPi stuff you want get that.
As doom said they were small heatsinks on most of the ones that they had done.As for the others I`m not real sure.
I think that the days of good stuff is about gone.I`ve been buy some of the `80`s and early 90`s stuff just because I think that it is much better in many ways.I`ve got a PPI that brought almost 20 years ago and use it daily and knock on wood it`s never missed a beat.And the new PPi stuff you want get that.
When I've shopped for cheap used or new car amps, I disregarded the stated specs and judged power by the fuse size and power in wire or terminal. You can't expect and amp to put out more than 60% of the fuse rating x 13V
Hi , sometimes I also think that there are no useable amps around anymore, but there are 🙂
Ever heard of Audison ? Not sure if they are sold in USA , it´s an Italian company, they do most of their amplifier design in Italy and also the assembly is (at least parts of it) in Italy .
ebay picture
They can be called " recommendable" for better speaker systems (ok, the one on ebay is totally burned 🙂 ) Also Signat has some very good products.
The last "big" amplifier I got for driving to 15" was the Hifonics zeus GenX , probably already a Korea-amp . But still very high output, low distortion and good assembly. the latest Hifonics models are real Korea-amps, and I guess that´s the reason for them beeing way cheaper than the series8 amps had been . And There are many damaged /broken GenXI amplifiers on ebay over here...... the new stuff (US-distribution by Maxxsonics, in Europe it´s Audiodesign ) is just not bulletproof anymore.
I was talking to a guy from Audiodesign homepage and he told me that all the models are made in korea now, incl. even some of the speakers, def. all amps are designed and made in Asia. He admitted that quality has changed by far and the "stuff" needed to get much cheaper for them to survive, although the bigger models are supposed to be better......... i think a lot of customers don´t care about the used technique rather than a funky amplifier outfit or woofers with neon-lights 🙂
BTW: The cheap Amp above using two Toshiba IC are called TZS - First Austria , the same amplifier is sold with the name "Rockwood - 4x400W)"
Ever heard of Audison ? Not sure if they are sold in USA , it´s an Italian company, they do most of their amplifier design in Italy and also the assembly is (at least parts of it) in Italy .
ebay picture
They can be called " recommendable" for better speaker systems (ok, the one on ebay is totally burned 🙂 ) Also Signat has some very good products.
The last "big" amplifier I got for driving to 15" was the Hifonics zeus GenX , probably already a Korea-amp . But still very high output, low distortion and good assembly. the latest Hifonics models are real Korea-amps, and I guess that´s the reason for them beeing way cheaper than the series8 amps had been . And There are many damaged /broken GenXI amplifiers on ebay over here...... the new stuff (US-distribution by Maxxsonics, in Europe it´s Audiodesign ) is just not bulletproof anymore.
I was talking to a guy from Audiodesign homepage and he told me that all the models are made in korea now, incl. even some of the speakers, def. all amps are designed and made in Asia. He admitted that quality has changed by far and the "stuff" needed to get much cheaper for them to survive, although the bigger models are supposed to be better......... i think a lot of customers don´t care about the used technique rather than a funky amplifier outfit or woofers with neon-lights 🙂
BTW: The cheap Amp above using two Toshiba IC are called TZS - First Austria , the same amplifier is sold with the name "Rockwood - 4x400W)"
much better
Great pics, now thats more like it, these look much better, all the amps I have are like this, not as big, but lots of smps devices, capacitors and output transistors. My guess is if you were to take the clamps off the top of the transistors they'd be as I described earlier, tip35/36 class if they are bipolar or irf mosfets if its a mosfet output stage.
How do these sound? Have you tried them in any sort of comparison to known good home audio equipment? I have been analysing the schematics and as far as I can see most of these are very, very generic AB amps. If I kill any of them doing my listening test I think I'm gonna replace the amps with two channels of parallel 3886 chips (4875?), sounds good, and has very good protection against abuse...
Stuart
Great pics, now thats more like it, these look much better, all the amps I have are like this, not as big, but lots of smps devices, capacitors and output transistors. My guess is if you were to take the clamps off the top of the transistors they'd be as I described earlier, tip35/36 class if they are bipolar or irf mosfets if its a mosfet output stage.
How do these sound? Have you tried them in any sort of comparison to known good home audio equipment? I have been analysing the schematics and as far as I can see most of these are very, very generic AB amps. If I kill any of them doing my listening test I think I'm gonna replace the amps with two channels of parallel 3886 chips (4875?), sounds good, and has very good protection against abuse...
Stuart
Hi
JBL , better say Harman, has used some home audio curcuits in their older amps. The white GTx (also known as Concord -ST and QD series) series amps have pretty good sound quality and fairly big DC-converters. Huge heatsinks and realistic power ratings, I remember those had been damn expensive over here. In some of those models they used the µPC1298 ( I think thats the right number) Voltage amplifier with Darlington-power stages. That resulted in 50-80W RMS per channel depending on the SMPS and very good and clear sound. In some better home amplifiers from Kenwood or Sony those µPC can be found. But those amps didn´t sell very good as they had been too expensive for the majority. A lot og people dont care what´s inside the box......stuff must be cheap and LOUD........ 🙂
I used to install ALTAI amps a lot a couple of years ago. They were inixpensive amps , huge heatsinks. Although made in Korea, those amps used very good parts and the biggest 2 channel amp delivered more than 500W RMS into a 4 Ohm load ....double SMPS and huge output stages. Sad the company doesn´t build those things anymore.
Last week I fixed a broken PG - ZPA 0.5 pretty good sounding amplifier , but for a 1kW amp they really should have used better heatsinks! Somehow it´s the American companies "doing the right thing" : o ))))))))
But there are a few German companies around, as well. This is a picture of a pure MOSFET power amplifier, delivers more than 2x80W RMS into 4 Ohms (no kiddin!) . Very small heatsink (they really get hot !!!) but those babies have been wonderful, also very expensive. 🙂 But they had programmable filters and stuff included. The company went out off business a couple of years ago
There had been a couple of models around, the cheapest (2x50W) starting with 300US$
JBL , better say Harman, has used some home audio curcuits in their older amps. The white GTx (also known as Concord -ST and QD series) series amps have pretty good sound quality and fairly big DC-converters. Huge heatsinks and realistic power ratings, I remember those had been damn expensive over here. In some of those models they used the µPC1298 ( I think thats the right number) Voltage amplifier with Darlington-power stages. That resulted in 50-80W RMS per channel depending on the SMPS and very good and clear sound. In some better home amplifiers from Kenwood or Sony those µPC can be found. But those amps didn´t sell very good as they had been too expensive for the majority. A lot og people dont care what´s inside the box......stuff must be cheap and LOUD........ 🙂
I used to install ALTAI amps a lot a couple of years ago. They were inixpensive amps , huge heatsinks. Although made in Korea, those amps used very good parts and the biggest 2 channel amp delivered more than 500W RMS into a 4 Ohm load ....double SMPS and huge output stages. Sad the company doesn´t build those things anymore.
Last week I fixed a broken PG - ZPA 0.5 pretty good sounding amplifier , but for a 1kW amp they really should have used better heatsinks! Somehow it´s the American companies "doing the right thing" : o ))))))))
But there are a few German companies around, as well. This is a picture of a pure MOSFET power amplifier, delivers more than 2x80W RMS into 4 Ohms (no kiddin!) . Very small heatsink (they really get hot !!!) but those babies have been wonderful, also very expensive. 🙂 But they had programmable filters and stuff included. The company went out off business a couple of years ago
There had been a couple of models around, the cheapest (2x50W) starting with 300US$
Re: much better
I am not sure as I have not had any decent speakers to test with yet, only cheap ones. But I will have a new car audio system in a week or so when I finish setting it all up.
I dont think they are comparable to home audio equipment unless you take them out of the car which requires a very big 12V PSU. A car is such a different enviroment to a home 😉
Stuart Easson said:
I am not sure as I have not had any decent speakers to test with yet, only cheap ones. But I will have a new car audio system in a week or so when I finish setting it all up.
I dont think they are comparable to home audio equipment unless you take them out of the car which requires a very big 12V PSU. A car is such a different enviroment to a home 😉
I don't have pics, but my Alpine MRV-F400 and MRV-F300 amps look similar to the PG stuff. Of course it's a Japanese amp, but still very rugged and durable. It's a 1994 model, and has been excellent. The heat sink seems to be adequate, it does get hot under prolonged coninuous usage, but it hardly ever sees that kind of usage, so that's okay.
For those eBay amps, I've actually been looking around. I used to have some amps that I bought for dirt cheap whic were real POS units, but the heat sink on them was reasonably massive. I wanted to make a couple of DIY amps, and the price that I paid for those POS units would be worth it for the heat sink, and maybe RCA jacks. I certainly wouldn't want anything else from inside of 'em.
I'd like to put a nice system in my wife's vehicle, since I end up driving it whenever we're all going anywhere. For that, I'd need at least 4 channels of amplifiction, maybe 5 if I wanted to add a sub (And of course I want to!) SO if you put up some of those amps in the trading post, I may look 'em up. 🙂
For comparing a car an ome amp:
This is really tricky. It's difficult to make a fair comparison, because there are such fundamantal differences in the circuits.
For example, a home use speaker is typically 8 ohms, and occasionally 16 nominal impedance. A car speaker is typically 4 ohm. If you run the car amp to a home speaker (I've done it, BTW) you get a much lower power output. This isn't necessarily a bad thing, and in fact, the end result was extremely satisfactory. I had done this in order to get a comparison of a home amp with my car amp. I just ran the sepaker cables out to the trunk of my car through a convenient window, and used my car stereo's remote control. The home amp was much louder, but the car amp was actually cleaner into an 8 ohm load in the house In the car, I'd have rated the performance as similar, but in the car comes with all the "in the car" problems, glass surfaces near your ears, small cabin without room for a full wavelength in a bass note...
I also tried running the home amp to the car speakers, but the protection circuits cut in at low to moderate volume, and it sounded bad. I guess 4 ohm speakers were incompatable. (Well, the label DID warn me...)
For those eBay amps, I've actually been looking around. I used to have some amps that I bought for dirt cheap whic were real POS units, but the heat sink on them was reasonably massive. I wanted to make a couple of DIY amps, and the price that I paid for those POS units would be worth it for the heat sink, and maybe RCA jacks. I certainly wouldn't want anything else from inside of 'em.
I'd like to put a nice system in my wife's vehicle, since I end up driving it whenever we're all going anywhere. For that, I'd need at least 4 channels of amplifiction, maybe 5 if I wanted to add a sub (And of course I want to!) SO if you put up some of those amps in the trading post, I may look 'em up. 🙂
For comparing a car an ome amp:
This is really tricky. It's difficult to make a fair comparison, because there are such fundamantal differences in the circuits.
For example, a home use speaker is typically 8 ohms, and occasionally 16 nominal impedance. A car speaker is typically 4 ohm. If you run the car amp to a home speaker (I've done it, BTW) you get a much lower power output. This isn't necessarily a bad thing, and in fact, the end result was extremely satisfactory. I had done this in order to get a comparison of a home amp with my car amp. I just ran the sepaker cables out to the trunk of my car through a convenient window, and used my car stereo's remote control. The home amp was much louder, but the car amp was actually cleaner into an 8 ohm load in the house In the car, I'd have rated the performance as similar, but in the car comes with all the "in the car" problems, glass surfaces near your ears, small cabin without room for a full wavelength in a bass note...
I also tried running the home amp to the car speakers, but the protection circuits cut in at low to moderate volume, and it sounded bad. I guess 4 ohm speakers were incompatable. (Well, the label DID warn me...)
Phoenix Gold
I had one of these amps a few years ago and still regret selling it. The build quality was fantastic and for a laugh I installed 2 KEF B110 units in the car to see what the sound was like. It was better than my home hi-fi which used a Mission Cyrus II at the time!
If they still make them like that - get one and keep it!
I had one of these amps a few years ago and still regret selling it. The build quality was fantastic and for a laugh I installed 2 KEF B110 units in the car to see what the sound was like. It was better than my home hi-fi which used a Mission Cyrus II at the time!
If they still make them like that - get one and keep it!
500w test setup...
Hi,
Thanks for all your replies...
I have got a 'test' rig I put together for the amps I've fixed, seems to be good for at least 500w, ie 40+amps at 12v, though most of these amps need 14.4v to deliver their best, I only get about 13-14v at the 45 amp mark.
After fixing an amp I put it into bridge mode and drive it full power into a 4 ohm test ladder. I tap a speaker off the middle of a resistive network of 48 x 0.68ohm/10w resistors, gives about 20db level reduction, otherwise I'd be even deafer, simulates driving 2ohms with both channels working as hard as they can...I'm gonna add some capacitance when I get back to make a better, more realistic test load.
I have a pair of parasound monoblocks driving the duettas at home, they get super hot after a little while of serious output, but so far haven't given up the ghost. I think the extrusions on the car amps are at least as big, though the surface area is hard to estimate.
I'm visiting with my parents in England right now, but as soon as I'm back at the ranch I'll be testing in earnest...results to follow.
I'm thinking of offering 2 dead for one fixed, what do you guys think of that idea? I am enjoying working on these things, but it's not clear I can make any money, but I know people with small collections of dead equipment they don't know how to fix, but would love to trade it for something they can use...
Stuart
Hi,
Thanks for all your replies...
I have got a 'test' rig I put together for the amps I've fixed, seems to be good for at least 500w, ie 40+amps at 12v, though most of these amps need 14.4v to deliver their best, I only get about 13-14v at the 45 amp mark.
After fixing an amp I put it into bridge mode and drive it full power into a 4 ohm test ladder. I tap a speaker off the middle of a resistive network of 48 x 0.68ohm/10w resistors, gives about 20db level reduction, otherwise I'd be even deafer, simulates driving 2ohms with both channels working as hard as they can...I'm gonna add some capacitance when I get back to make a better, more realistic test load.
I have a pair of parasound monoblocks driving the duettas at home, they get super hot after a little while of serious output, but so far haven't given up the ghost. I think the extrusions on the car amps are at least as big, though the surface area is hard to estimate.
I'm visiting with my parents in England right now, but as soon as I'm back at the ranch I'll be testing in earnest...results to follow.
I'm thinking of offering 2 dead for one fixed, what do you guys think of that idea? I am enjoying working on these things, but it's not clear I can make any money, but I know people with small collections of dead equipment they don't know how to fix, but would love to trade it for something they can use...
Stuart
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