| carlosfm |
I was talking a GC with 1000 to 1500uf capacitance.
If you go higher in capacitance with these chips you will affect midband and treble, it will sound very bad indeed, I tested.
Not good for driving the woofer in bi-amp mode with a two way speaker.
Maby for driving the woofer on a 3 way speaker, if the crossover frequency is low.
Useless.
It's a compromise, no way around this other than to regulate.:D |
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| chris ma |
| quote: | Originally posted by carlosfm
I was talking a GC with 1000 to 1500uf capacitance.
If you go higher in capacitance with these chips you will affect midband and treble, it will sound very bad indeed, I tested.
Not good for driving the woofer in bi-amp mode with a two way speaker.
Maby for driving the woofer on a 3 way speaker, if the crossover frequency is low.
Useless.
It's a compromise, no way around this other than to regulate.:D |
Carlos,
I have a concern with your statement. That's what I am planning to do (4 times) a 1000uf GC kit to power 4 times 12 inch drivers in two H frames as a two channel subwoofer. So in your opinion it is not going to work for me unless I go regulated?
Best Regards,
Chris |
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| carlosfm |
Chris,
Actually I first regulated a GC some months ago, the amp I made for my sub.:cool:
Two OPA549s in parallel, regulated with LM338.
I liked so much the results that I had to try this on a normal GC amp.
I did, and I'll never go back to unregulated.
My oppinion is yes, you have to regulate.
A sub with unregulated PSU and 1000uf capacitance, no way.
I recommend that you use a pair or LM338s (for the two voltage rails) for each 2 chips, no more.
BTW, 12 inch drivers?:eek:
What impedance?
My 10 inch driver has two 4 ohm coils and I use them in series, so that's 8 ohms.
I recommend that, in case of your drivers are 8 ohms, use two in parallel (4 ohms) and drive them with a pair of LM3886 in parallel.
I think that may be a better option than one chip/one woofer.
Use two LM3886 for each sub (with two woofers), two OPA549s, or one LM4780 with both channels in parallel.
Edit: in the end, a pair of regs per channel.:D |
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| B.I.G |
i have a 2x45Vac transformer and want to regulate it to about 2X31V dc will the LM338 handle the DC voltage in my case 60V ??
What is the maximum input voltage on this thing ??:rolleyes: |
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| Pedja |
Will handle it but will be limited to 1A then.
The maximum is at 40V of Vin-Vout difference. |
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| jackinnj |
| if you can get to Pennsylvania this week (U.S. Government Liquidation ends Feb 3) -- these Lambda 28V, 19.5 amp power supplies will probably go for $35 each ! Original cost was about 400X that -- and they are in the original packaging -- perfect for a bridged GC amplifier: |
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| seftali |
| Why nobody uses solid tantalum caps with lm338 as National Semi. recommends ? |
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| CarlosT |
| Good question... :D |
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