So what about my queries regarding a bridged Leach Amp delivering 1200watts into a 4 ohm load. Ofcourse, I had directed my queries to djk, but in case any one else would like to contribute his bit....
Thanks,
Thanks,
"Thank you very much for the information. Do you mean to say that a total of 16 output devices (MJ21193/94) would do for a 1200watt bridged amp ie., 4 devices per bank of one amplifier? That seems rather easy."
It is that easy. You will need about 1*C/W per output device for heatsinking. This will mean one sink for the + rail and one for the - rail, both isolated from the chassis, and with the transistors mounted without insulators. Metal outputs and a 100CFM fan.
"Another question is - would the thermal sensing be sufficient as shown in the Leach schematic ie., with diodes or do we need to use TO39 transistors in diode mode for better sensing?"
Crown uses 1N400X diodes just as in the Leach. I have also used an isolated case TO220 transistor (2SA1306/2SC3298).
"You have suggested 55-0-55 volt 2kVa transformer. That would result in a voltage of about 75-77 volts. Isn't this too high a voltage for the standard Leach design, notwithstanding changing output devices from MJ15003/15004 to MJ21193/21194 and drivers from MJE15030/15031 to 2SC3281 or 2SC5200 and 2SA1302 or 2SA1943 respectively?"
Its mainly a function of the voltage ratings of the transistors you choose, and adjusting the bias resistors to suit. The Heathkit AA1800, a Leach design, ran ±100V on the front end (with the series connected outputs). Watch the power level in the second voltage amplifiers, and heatsink them properly. With the diff pairs being cascoded, you can run about any voltage you need.
"In the triple emmiter follower stage can the second transistors be changed from 2N3440/2N5416 to 2SB649 and 2SD669 as they are higher voltage/current devices. Also the higher voltage types viz., 2N3439 and 2N5415 are currently not available. Hence, would the lower voltage 2N3440/2N5416 be sailing a bit too close to the wind with your suggested power supply?"
A 2N3440 will have no problems at ±75V, the 2SB649/2SD669 are a fine pair too. Remember to heatsink these properly and de-rate for temperature. Even though the TO126 part is rated at 20W, it is plastic and must be de-rated to a lower temperature than the TO5 metal parts. I never run either of these above about 1.5W
It is that easy. You will need about 1*C/W per output device for heatsinking. This will mean one sink for the + rail and one for the - rail, both isolated from the chassis, and with the transistors mounted without insulators. Metal outputs and a 100CFM fan.
"Another question is - would the thermal sensing be sufficient as shown in the Leach schematic ie., with diodes or do we need to use TO39 transistors in diode mode for better sensing?"
Crown uses 1N400X diodes just as in the Leach. I have also used an isolated case TO220 transistor (2SA1306/2SC3298).
"You have suggested 55-0-55 volt 2kVa transformer. That would result in a voltage of about 75-77 volts. Isn't this too high a voltage for the standard Leach design, notwithstanding changing output devices from MJ15003/15004 to MJ21193/21194 and drivers from MJE15030/15031 to 2SC3281 or 2SC5200 and 2SA1302 or 2SA1943 respectively?"
Its mainly a function of the voltage ratings of the transistors you choose, and adjusting the bias resistors to suit. The Heathkit AA1800, a Leach design, ran ±100V on the front end (with the series connected outputs). Watch the power level in the second voltage amplifiers, and heatsink them properly. With the diff pairs being cascoded, you can run about any voltage you need.
"In the triple emmiter follower stage can the second transistors be changed from 2N3440/2N5416 to 2SB649 and 2SD669 as they are higher voltage/current devices. Also the higher voltage types viz., 2N3439 and 2N5415 are currently not available. Hence, would the lower voltage 2N3440/2N5416 be sailing a bit too close to the wind with your suggested power supply?"
A 2N3440 will have no problems at ±75V, the 2SB649/2SD669 are a fine pair too. Remember to heatsink these properly and de-rate for temperature. Even though the TO126 part is rated at 20W, it is plastic and must be de-rated to a lower temperature than the TO5 metal parts. I never run either of these above about 1.5W
>no PWM / digital amplifier...>
and why not if i may ask?
the sound quality is fine for hifi and the power levels (1000w full range and 2000w+ bass) should certainly be enough for most speakers i know of.
combine with a switch mode supply and in my mind you have a superb amplifier for pa-band-disco or similar.
rgds k madsen - www.cadaudio.dk
and why not if i may ask?
the sound quality is fine for hifi and the power levels (1000w full range and 2000w+ bass) should certainly be enough for most speakers i know of.
combine with a switch mode supply and in my mind you have a superb amplifier for pa-band-disco or similar.
rgds k madsen - www.cadaudio.dk
For Km ,
1. Becouse hi-fi audio freaks do not understand the needs of pro or semi-pro users .
2. Becouse this guys think like that :
- Pro - Amplifier = Loud but not Hi-Fi and
- If you want to play loud , you don't deserve our respect.
- We have best ears in hole worlds and we hear the switching noise.
3. Becouse they do not understand ( or maybe do not want to understand) the major improvements in PWM and SMPS technology .
4. Becouse old is good and new is bad.
5. Becouse too many people try to sell old bipolar cheap design at huge prices .
1. Becouse hi-fi audio freaks do not understand the needs of pro or semi-pro users .
2. Becouse this guys think like that :
- Pro - Amplifier = Loud but not Hi-Fi and
- If you want to play loud , you don't deserve our respect.
- We have best ears in hole worlds and we hear the switching noise.
3. Becouse they do not understand ( or maybe do not want to understand) the major improvements in PWM and SMPS technology .
4. Becouse old is good and new is bad.
5. Becouse too many people try to sell old bipolar cheap design at huge prices .
hi.
djdan im afraid there is some truth in your points 😉
per-anders i have a question for you after visiting your site;
you wrote: >IcePower makes class D amplifier modules, best in the world. 1000 watt out in 1 x 4 x 4 inches!>
how do you know they are the best , did you really hear all the others (or which one of them did you hear and compare to icepower amp)?
the 1000w is a subwoofer amp bw. limited to 3 khz , are you still sure its the best in the world?
rgds k madsen - www.cadaudio.dk
djdan im afraid there is some truth in your points 😉
per-anders i have a question for you after visiting your site;
you wrote: >IcePower makes class D amplifier modules, best in the world. 1000 watt out in 1 x 4 x 4 inches!>
how do you know they are the best , did you really hear all the others (or which one of them did you hear and compare to icepower amp)?
the 1000w is a subwoofer amp bw. limited to 3 khz , are you still sure its the best in the world?
rgds k madsen - www.cadaudio.dk
djdan said:
There ARE people that have built and fixed both PA and "high end" audio amplifiers, and DO understand the needs of different users.
I generally do not recommend PWM amps for DIY, especially not for a beginner. If you can buy a kit and connect a transformer and make a case, well... alright. But you will probably not learn much, and if something goes wrong, a PWM / SMPS amplifier circuit is not very easy to understand / fix for a beginner.
The PWM amps I had were unreliable. The blew up all the time. They had a somewhat cold sound (no switching noise 😉 ), but were ok for the subwoofers or fullrange for disco music. Sometimes we had problems with the HF they put on the power lines. Especially when bands brought their own (yes, crappy) equipment.
Because old is good and new is bad? Not quite. But the opposite is also wrong. When the first transistor amplifiers were sold, they sounded like crap. The first generation of CD players sounded like crap. And so on... A new technology often brings "major improvements" - but it also introduces new problems... A couple of years of experience is needed to get them fixed. I've tried PWM/SMPS and to me it seems some more years are needed.
I don't mind anyone to disagree, but I don't like being called prejudiced.
km said:
I haven't seen any class D amp with better data AND smaller physical size. The 500 W full range module is something.
hi.
per-anders, you didnt hear any of them did you?? 🙂
ok , did you measure the specs then??
do you say that because an amplifier has low thd specs it is a good amplifier? 🙂
this certainly makes it easier to make good amplifiers in the future (according to your ideas), even many of them we thought werent very good are suddenly very good , yes perhaps among the best in the world (hmm).
i thought this idea sort of faded away when things like TIM came around and when people started to listen to things and compare stuff.
ok now you found out that the 1000w perhaps isnt the best in the world after all , may i kindly suggest that you listen to the 500w also and compare it with a couple of other types (could be good pwm or normal types).
rgds k madsen - www.cadaudio.dk
ps. perhaps its a good idea to praise things you have actually heard.
per-anders, you didnt hear any of them did you?? 🙂
ok , did you measure the specs then??
do you say that because an amplifier has low thd specs it is a good amplifier? 🙂
this certainly makes it easier to make good amplifiers in the future (according to your ideas), even many of them we thought werent very good are suddenly very good , yes perhaps among the best in the world (hmm).
i thought this idea sort of faded away when things like TIM came around and when people started to listen to things and compare stuff.
ok now you found out that the 1000w perhaps isnt the best in the world after all , may i kindly suggest that you listen to the 500w also and compare it with a couple of other types (could be good pwm or normal types).
rgds k madsen - www.cadaudio.dk
ps. perhaps its a good idea to praise things you have actually heard.
amt-freak you wrote;
>The PWM amps I had were unreliable. The blew up all the time. They had a somewhat cold sound >
>I've tried PWM/SMPS and to me it seems some more years are needed>
what pwm amps were they?
since you seem to have some real life experience with pwm amps i think your posting would be more valuable if you told us a bit more details , ok?
rgds karsten madsen - www.cadaudio.dk
>The PWM amps I had were unreliable. The blew up all the time. They had a somewhat cold sound >
>I've tried PWM/SMPS and to me it seems some more years are needed>
what pwm amps were they?
since you seem to have some real life experience with pwm amps i think your posting would be more valuable if you told us a bit more details , ok?
rgds karsten madsen - www.cadaudio.dk
Well, keeping the distortion down is a good start if you are heading towards good sound. You can agree to that at least, km?
But how do you change a switching amplifier from sounding cold to sounding warm? Not an easy task. If someone could tell me then I would be very interested to know.
The reason why switching amplifiers came up in this thread from the beginning was because DJ BASS AMP needed a powerfull subwoofer amp. No big difference if the sound is warm or cold in that application I think. Then the 1000W Bang Olufsen amp would perhaps be hard to beat regarding size and THD.
/Marcus
PS. There is a patent on a soft switching half bridge. Maybe that could make the sound warmer? Pat no 6304137 in the US.
But how do you change a switching amplifier from sounding cold to sounding warm? Not an easy task. If someone could tell me then I would be very interested to know.
The reason why switching amplifiers came up in this thread from the beginning was because DJ BASS AMP needed a powerfull subwoofer amp. No big difference if the sound is warm or cold in that application I think. Then the 1000W Bang Olufsen amp would perhaps be hard to beat regarding size and THD.
/Marcus
PS. There is a patent on a soft switching half bridge. Maybe that could make the sound warmer? Pat no 6304137 in the US.
I am not an natural english speaker so I really don't understand what is a cold sound or warm ? It is something about frequency or maybe is only a subjectivity matter ?
How it look a warm ( or cold ) sound on osciloscope ?
How it look a warm ( or cold ) sound on osciloscope ?
hi.
i dont think there is a simple relation between good specs and good sound.
you can read more about the sound quality of icepower amps at classd.org , apparently he listened to them 🙂
best in the world? , i dont think so.
i think the icepower modules came up because p-a recommended them (stating they are the best in the world on his site) and partly because amt-fan recommended not to use pwm amps 😉
its not clear to me that dj bass amp was talking about a subwoofer amp
(snip ; i need 2 circuits..... of amplifiers
1) for 2 speakers - 600W RMS 8 Ohm ani one
2) for 2 subs - 1500W RMS 4 Ohm ani one)
i cant comment on the circuit you mention or on ideas to improve the sound quality and specs we have been testing.
btw. is it possible to buy the icepower modules?
please note that the amplifier modules need a power supply , if this is a toroid of say 15 kgs + capacitors etc, i dont think its very important if the amp is 10x10 cm or say 15x15cm , do you?
again i think its a much better idea to use a switch mode supply with pwm amps, dont you?
for applications like this one i would not recommend to use a pwm (or other) amplifier without protection circuits this could be expensive , i think this rules out several of the ones mentioned.
rgds karsten madsen - www.cadaudio.dk
i dont think there is a simple relation between good specs and good sound.
you can read more about the sound quality of icepower amps at classd.org , apparently he listened to them 🙂
best in the world? , i dont think so.
i think the icepower modules came up because p-a recommended them (stating they are the best in the world on his site) and partly because amt-fan recommended not to use pwm amps 😉
its not clear to me that dj bass amp was talking about a subwoofer amp
(snip ; i need 2 circuits..... of amplifiers
1) for 2 speakers - 600W RMS 8 Ohm ani one
2) for 2 subs - 1500W RMS 4 Ohm ani one)
i cant comment on the circuit you mention or on ideas to improve the sound quality and specs we have been testing.
btw. is it possible to buy the icepower modules?
please note that the amplifier modules need a power supply , if this is a toroid of say 15 kgs + capacitors etc, i dont think its very important if the amp is 10x10 cm or say 15x15cm , do you?
again i think its a much better idea to use a switch mode supply with pwm amps, dont you?
for applications like this one i would not recommend to use a pwm (or other) amplifier without protection circuits this could be expensive , i think this rules out several of the ones mentioned.
rgds karsten madsen - www.cadaudio.dk
FYI, all of you, read some on the improved ICE design from danish highend company Acoustic Reality.
Tested in Danish High Fidelity magazine some months ago, they feel its the best amp on the market with a good margin.
Haven´t listened to it myself yet but I sure will.
When the guys on HF writes like that about a product then it´s time to open up the eyes/ears IMO.
/Peter
Tested in Danish High Fidelity magazine some months ago, they feel its the best amp on the market with a good margin.
Haven´t listened to it myself yet but I sure will.
When the guys on HF writes like that about a product then it´s time to open up the eyes/ears IMO.
/Peter
hi.
it would be great to have reviews from a lets say a bit more independant or objective source 😉
seems like the discussion is getting a bit o.t. and reminds me of a similar discussion some time ago.
what are the changes in the acoustic reality amp compared to std. icepower modules then?
btw. seems like dj bassamp left us some time ago....
rgds - karsten madsen - www.cadaudio.dk
ps. if we make a thread discussing thing we actually heard i think it would be kind of small 😉
it would be great to have reviews from a lets say a bit more independant or objective source 😉
seems like the discussion is getting a bit o.t. and reminds me of a similar discussion some time ago.
what are the changes in the acoustic reality amp compared to std. icepower modules then?
btw. seems like dj bassamp left us some time ago....
rgds - karsten madsen - www.cadaudio.dk
ps. if we make a thread discussing thing we actually heard i think it would be kind of small 😉
"what are the changes in the acoustic reality amp compared to std. icepower modules then?"
No idea, but the distortion seems to be lowered though, especially in the high range (not that it means everything).
"ps. if we make a thread discussing thing we actually heard i think it would be kind of small "
lol... hehe 🙂
/Peter
No idea, but the distortion seems to be lowered though, especially in the high range (not that it means everything).
"ps. if we make a thread discussing thing we actually heard i think it would be kind of small "
lol... hehe 🙂
/Peter
I'm not a native speaker, either. We use the same words ("warm" and "kalt") in German. You cannot easily measure a warm or cold sound or see it on an oscilloscope. Old solid state designs often sound cold (harsh, sharp, lots of hiss) whereas tube amps generally seem to sound warm. It's hard to describe. How would you explain the difference between "red" and green" in words? "Exciters" are effect units used in recording (mostly on voices) to make them sound "warmer". They add second-order distortion.
Can anyone suggest recordings that show the difference between cold and warm? (Maybe we should open a new thread for that. "Describing sound in words" or something like that.)
Back to topic:
Sound quality doesn't matter much for a sub amp. Power does. My point against a PWM/SMPS was:
What do you think about a PA-300 or maybe PA-600, bridged to deliver 600 or 1200W RMS into 8 Ohms? Or a project from www.aussieamplifiers.com. Those circuits are very simple and rugged. Probably they are even cheaper, although they do need big transformers, caps and heatsinks. Where's the advantage of using a PWM kit with a "standard" (non-SM) power supply? They are more expensive than a surplus heatsink and a bunch of power transistors.
They were commercial PA amps from various brands. All bought between '97 and 2000 as new. There are not many brands. I think we had them all. They were good but not in the same league as our older non-PWM amps. (they were way lighter, but sounded worse and made more trouble) We intended trying the Thel Audio PWM module to make some multichannel amps for monitoring, but it was discontinued because of EMV problems before we could order. I HAVE NO EXPERIENCE with any DIY PWM modules. I hope they are better than the commercial pro amps.
http://www.thel-audioworld.de/module/digital/digital.htm
This is why Thel discontinued their digital Amp. It's German, but I'll try to translate if anyone is interested.
At the power that Dj BASS AMP are talking about I think he is better off buying a kit with a PWM-amp. Building a PWM-amp from scratch is not easy. It's not that easy to build a decent class AB at those powers.
I don't know if there are kits available for PSU's though, so it'll probably have to be a massive toroid xformer for that.
/Marcus
I don't know if there are kits available for PSU's though, so it'll probably have to be a massive toroid xformer for that.
/Marcus
Karsten (km), about IcePower, I have now added a "?" in my link list "Best in the world(?)".
No I haven't listened to all existing class D amps. I notice also that you sell class D amps. Best in the world?
This thread is about Mr DJ of Israel who wants power and want it cheap.
I still recommend him to build something smaller to start with. 1500 W is nothing for a newbeginner.
No I haven't listened to all existing class D amps. I notice also that you sell class D amps. Best in the world?
This thread is about Mr DJ of Israel who wants power and want it cheap.
I still recommend him to build something smaller to start with. 1500 W is nothing for a newbeginner.
Check here for a very simple and powerful class AB amplifier:
http://www.diyaudio.com/forums/showthread.php?postid=123517#post123517
http://www.diyaudio.com/forums/showthread.php?postid=123517#post123517
A very nice copy of a BGW750, but with a NE5534 instead of the LM318 used in the BGW.
The Crest 3500 was also the same front end, but with a LF351 .
There is no need to use the TIP35/36 for the pre-drivers, the MJE340/350 are more than adequate here.
A universal and widely accepted circuit for PA use.
The Crest 3500 was also the same front end, but with a LF351 .
There is no need to use the TIP35/36 for the pre-drivers, the MJE340/350 are more than adequate here.
A universal and widely accepted circuit for PA use.
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