| soundNERD |
What is the most powerful opamp avaliable, not including those $500 dollar ones we're always talking about. I would assume it is some OPA chip, but I have no idea which one.
Would anybody be able to tell me what some of the highest power chipamps are?
What I need to do is make a subwoofer, and none of the chips I have produce enough power, like the 3886, 4766, 4780, opa541, opa549, etc. I need at leat 200-300 watts RMS of power, and since the speaker is 8ohm, bridging is possible and is what I am going to do to get the most power.
Or, if somebody has come up with a good pcb for the lm4651/4652 yet, I would like to try it.
Thank you! |
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| peranders |
If you need 200 watts I think a "das Modul" will fit you (4 x LM3886)
For a sub amp it is just as easy to make a MOSFET amp. It's trivial to drive mosfets up to max 10 kHz and with good quality from 10-200 Hz. Maybe you should check stuff from Rod Elliott? |
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| soundNERD |
Thanks for the reply. If you have time, would you mind suggesting a good schematic to start with?
And, like I said, any working board for a 4651/2 amp would be appreciated.
Finally, is the das module the same as the bridge/parallel 3886 amp? because I am building one of those right now.
also, I was just wondering, what is the most powerful opa chip like i asked in the first post? |
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| raidfibre |
LM12CLK TO-3 package, 80 watts rated.
$16.90 :eek: |
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| janneman |
Per-Anders,
Sorry to disagree with you (again...), but to me the LM12 is a more advanced design than the other GC chipamps. It has a fully symmetrical output stage. With a gain of 10 or more, it can handle 1uF cap loads. This would be the killer GC amp for 'difficult' full range speakers, with 10A current capability, generous SOA and excellent stability.
Jan Didden |
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| PMA |
| GC = simple-to-do + trust (blind faith;) ). Nothing more, nothing less. |
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| raidfibre |
| He asked for the most power opamp. The LM12CL is not advertised as an audio amp so I was just citing the most power non-audio-specific opamp I know of. |
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| janneman |
| quote: | Originally posted by PMA
GC = simple-to-do + trust (blind faith;) ). Nothing more, nothing less. |
Indeed, and I think the LM12 is even easier to use. Only 4 pins..;)
Jan Didden |
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| peranders |
| quote: | Originally posted by janneman
Sorry to disagree with you (again...), but to me the LM12 is a more advanced design than the other GC chipamps. |
From what I can see LM3886 is substantially faster and has also a bit lower distortion, less noise.
The difference isn't huge and I have never heard LM12 so I'll guess this won't create a big debate. |
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| carlosfm |
I think that TI discontinued the LM12.
Anyway, I tested the OPA541AM (TO-3), it has 10A current too.
TI asked $80:eek: for each of these beauties, but it seams that now they are not available.
While it has very good bass, the rest is not up to the standards of sound quality of an LM3886, or LM3875, or LM4780, or even the LM1875.
But it's very good indeed, some people may prefer the "warmer" sound of the OPA541.
I just feel that it doesn't have that magical midband, treble and detail of the National chips.
The LM3886 has "typically" 11.5A current, and it's what I use.
I don't use the LM3875 for a long time... |
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| carlosfm |
Sorry for the confusion, yes, National.
Although they don't have samples, they still sell them. |
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| demogorgon |
the first thing that came to my mind would be the combo of the LM4651 and 4652. it's a class D subb amp delivering 170w of power.
just a thought
marius |
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| ir |
although technically cheating, bridging (or paralleling) the two amps inside an LM4732 (50Wx2) or an LM4780 (60Wx2) would give you around 100 and 120Watts respectively from a single package
would save some PCB space too |
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| soundNERD |
| quote: | Originally posted by demogorgon
the first thing that came to my mind would be the combo of the LM4651 and 4652. it's a class D subb amp delivering 170w of power.
just a thought
marius |
yep, thats what I thought, but I can't find a decent pcb i can make myself. Anybody have one? 1 layer preferred, but two sided can be done. |
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| raidfibre |
| The datasheet has a board layout but it is unfriendly to most methods of prototyping since it has very small clearances between traces. I would like to do a run of these boards at a professional facility but I don't have the money or time to finance it. |
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| carlosfm |
Contact TI, they sell the PCBs that they have on their appnotes.
Maby they have that one available. |
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| raidfibre |
If class D is what you want I have a new design for a class D amp in progress. It should be able to deliver a lot of power and be fairly simple.
More info as I figure out if it's practical. |
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| soundNERD |
raidfibre, Yes, I would really appreciate the schematic and pcb design when you finish it.
Do you have any idea about what the power output will be? and what impedence it can drive. I'm using a Rockford Punch 12" sub (I know its a car sub but it sounds good) which is 8ohm so it shouldn't matter but if I were ever to upgrade to a 4ohm or DVC in parallel so 2ohm?
What is it based on? using transistors, or chips like the 4651/2?
Thanks!
-Mike |
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| raidfibre |
diyAudio is great because there's always someone interested in building an amp or power supply.
The output will be N/P MOSFETs in a totem pole configuration. I don't know if my theory is correct on the control portion yet so I don't want to say too much about it at the moment but I'm glad you're interested. I will have some more information soon I hope. |
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| abid_rehan |
Raidfibre:
Look forward to u in posting those layouts or schematics, I too want to build a sub, I have lots of chips like LM3886 (15+), OPA541 (12), OPA549(12) andlots of others lying around and want to put hem to use, I u like u could send those schematics and layoutsat my email.
Appreciate help in advance. |
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| niconoise |
| have you looked at the apex microtechnology products? they are effectively power op amps and they seem to cover quite a range of voltages and currents. they are expensive, however. |
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| soundNERD |
| quote: | Originally posted by niconoise
they are expensive, however. |
Expensive isn't even the word to describe them... Wheres the sample button?? :):) |
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| abid_rehan |
| quote: | | have you looked at the apex microtechnology products? they are effectively power op amps and they seem to cover quite a range of voltages and currents. they are expensive, however. |
One must be having pretty serious erros in the upper compartment to go for these microchips, imagine for a moment LM4651/4652 paralleld or LM3886 bridged/paralleld x 8 will cost fraction of what APEX is charding for "1" chip? |
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| carlmart |
It's interersting that no one, as far as I know, has used Apex chips for an audio amp. Probably not because it's expensive, because if it was good there should be someone using it, particularly in high end designs.
They are probably not as good sounding for audio applications as others.
Carlos |
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| Don Nebel |
| Hello, I was going through old (4/1988) issues of Speaker Builder magazine and found an article by A.L. Newcomb. He used a LM12CK op-amp for a 80 watt sub bass power booster. In the same article. there are schematics and PCB artwork for mono and stereo amplifiers using the LM12 op-amp. According to Newcomb the stereo version of the amplifier can be bridged for 200 watt output. Don Nebel |
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| owen |
Now, the Apex opamps I believe are commercially used by ATC in thier active monitors...
Owen |
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