- hi to all I'm planning to made build my own bpa300 base on bpa200 from
national. so I'm choosing more parallel 6xLM3886 per channel. for the power
I'm being after of 8A 25v-0-25v
@J cearsound can you give me a copy of your schematic of pre-amplifier and
3 band equalizer for my references.
- Watts per channel?
- @Henzzman, Thanks for your comments. I have plans to do an upgrade in this
Amp and increase the total capacitance to at least 10,000uF on each rail.
For sure, bass will be better. Thanks.
- @cumesoftware Your solution is very good.
- Nice, one of the more cleaner cases i've seen! What power transformer are
you using? I need to finish my project and post it up to. Good job man!
- Yes, I did the additional windings of coper wire # 14 in order to up the
final rail DC voltage to 35v. Actually these extra turns adds +3vac to each
side (+v, -v), it is in series with the main secondary windings. I did this
solution in order to increase the power output of amplifier.
- @xSlavic Good tips, thanks and G. Luck.
- Thanks! I prefer the LM3886 instead of LM4780 because in case of burn-out
(blow-out) of one channel, is more simple and more cheap the repair. If one
channel of LM4780 blows-out, I would need to replace entire LM4780. Also
consider that the two separated assembled LM3886 have better heat
dissipation so less chance to fail. And the LM3886 is more popular and easy
to find anywhere.
- In your opinion would it be fair to call theLM3886 a high-end amp?
- If you use high-end components it will be high end.
- Is that monitor a W2261VP?
- @cumesoftware This is a mystic belief. You are correct, there will have
more voltage drop than a single bridge configuration. To my understand I do
not see any improvement using dual diode bridge, in my projects I aways use
one bridge. Now if you have 2 independent power supplys for each channel
(double trafo, bridge and filter caps) it is another history, will result a
great improvement on sound, because there will not have intermodulation
distortion between the 2 channels.
- @majorov2 Hi, thanks for the comment! The analog VU is a matter of taste,
someones like more the bargraph VU. Are you assembling a 4 channel amp with
- Nice work, well done. It's Top Notch!
- Can you upload schematic?
- The LM3886 has a very clean and good sound to hear, above what I expected.
But I don't think is a high-end amp.
- Jeff Rowland would disagree with you. He used six LM3886 per side in his
Model 10 amp and his Concentra integrated amp. He is a particularly gifted
high-end designer who isn't afraid to try things that don't fit the
paradigm, and if they work well then he puts them into production. These
days he is also using Class-D ICEpower amplifier modules in his lower end
amps, and Class-G topology amps with switch-mode PSUs and Class-AB output
stages in his high-end units. Check out his work when you can.
- @omgitsonlyme I never had this situaton and never had a 3886 burned so far.
But certainly you may burn it out with only + rail and GND, due to
unbalanced operation, when high current may flow over internal transistors.
- @majorov2 ptivet,ia toje sobiraius delati na 4 lm3886 2x300 watt
,componenti ne hvataiut ,non-inductive resistors ,tak shto good luck
- @dhrdan Thanks for your kind words! Yes, a pretty much hours of work
dedication to get this project fineshed. Please advise when you post your
project. Here is the spec of power supply: Transformer = Toroid 240VA Vout
= 24+24Vac RMS Imax = 5Amps Vrails = +35 / - 35Vdc without load. Filters:
6900uF (+) / 6900uF (-) Rectification: one bridge of diodes 6amps max
- @Cesarsound1 I presume,that all the pcb-s were pc made?All in all nice
amp,but the capacitance could be a bit bigger.Friend built one too,he had
approx. same powerful transformer,but 15,000mkf philips caps and the bass
was better,because we tested with smaller capacitance before and the larger
capacity made the sound more dynamical on higher output levels.
- gahagsyw wrote: That's a lot of work! Nicely done, very accurate. I like
the VU meters. Can you tell what power supply have you used? R: please see
below the reply. Thanks.
- Complementing: The power supply specifications: Trafo = Toroid 240VA Vout =
24+24Vac RMS Imax = 5Amps Vrails = +35 / - 35Vdc without load. Filters:
6900uF (+) / 6900uF (-) Rectification: one bridge of diodes 6amps max.
- @cumesoftware Thanks for watching and comment!
- @HeavyMetal80sRules Hello, I'm fine, thanks for your comments. To connect
the VU I used 2 germanium diodes (1N60) and 2 resistors 10k for each VU.
This circuit is rectifying the audio output of LM3886. If needed I can send
the schematic to you.