But if my memory serves well, it is SMD, isn't it? And I remember it having around 18 pins instead of 8....
Apparently the original inspiration for Mauro's MyRef was the Musical Fidelity A370, so I had a look at the MF schematic.
It also used our same chip, an LM318, to drive a discrete amplifier with output MOSFETs.
I do remember that in its time the A370 had very good reviews and was considered a reference for "tube like" audio quality. Has anyone listened to it?
Perhaps the LM318 is the best choice really, but I think listening to other types might reveal subtleties that do not show in simulations.
Even if I am going too deep on my "blasphemous questions", what about other power chips instead of the LM3886? To get more power I mean.
It also used our same chip, an LM318, to drive a discrete amplifier with output MOSFETs.
I do remember that in its time the A370 had very good reviews and was considered a reference for "tube like" audio quality. Has anyone listened to it?
Perhaps the LM318 is the best choice really, but I think listening to other types might reveal subtleties that do not show in simulations.
Even if I am going too deep on my "blasphemous questions", what about other power chips instead of the LM3886? To get more power I mean.
Changing the power chip is probably outside the limits of this thread.
Chips like the Sanyo STK4040 II, which was used on some Marantz receivers, might be used on a project following Mauro's proposal. But it would be impossible to adapt to the pcb and all that.
But Mauro did try the LM3875, and some claim it sounds better than the LM3886. Unfortunately power output is the same.
Chips like the Sanyo STK4040 II, which was used on some Marantz receivers, might be used on a project following Mauro's proposal. But it would be impossible to adapt to the pcb and all that.
But Mauro did try the LM3875, and some claim it sounds better than the LM3886. Unfortunately power output is the same.
Yes it's SMD but it's a normal SO8 single opamp, it can be used with a BrownDog (or similar) adapter
An externally hosted image should be here but it was not working when we last tested it.
First experimental version of the MyRef were using TDA chips, Mauro was satisfied and published the project only when he started using LM3886
Can someone tell me if Mauro's Evolution was intended to be a higher powered version of the MyRef design. It sounds like it but unfortunately I can find little information from people who built it or if it disappeared into the "Retail" cloud.
My_Evo it's fundamentally a SMD MyRefC with optional double Howland Current Pump, DC-Servo to get rid of C9, shunt regulated LM318PS.
The double pump gives it more authority, more DF, better 4 Ohm drive and increase, if I remember correctly, 8 Ohm output to 50W and 4 Ohm to 60W
Dario, What happened to the My_Evo? Did it go commercial and did that increased "authority" translate to a perceived increase in power?
And.... does anyone have the leverage/relationship/rapport to drag Mario back into the DIY flow at this point? It sure sounds like the right time.
And.... does anyone have the leverage/relationship/rapport to drag Mario back into the DIY flow at this point? It sure sounds like the right time.
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Indeed, if using the 3875 you will have less power for 4 ohms loads.
But if am not wrong the chip-based amplifier popularity started inspired by the 47-Labs amplifier, the Gaincard, which used an LM1875.
That amp was also low powered, and only very efficient speakers could be used with it for higher levels. Preferably horn-loaded.
The first Gainclone design, proposed by Thorsten Loesch (who I think invented the word Gainclone), did have three design premises, based on the 47 Labs philosophy:
1) Distance between parts was minimal.
2) Circuit was inverting, which reduced number of parts and improved distortion.
3) Used the LM3875, which might be considered a higher power version of the LM1875.
So if your load is not critical, using the 3875 could be interesting.
Not for me, as I don't like horn-loaded speakers, but I think it should be considered a very likely option for DIY.
But if am not wrong the chip-based amplifier popularity started inspired by the 47-Labs amplifier, the Gaincard, which used an LM1875.
That amp was also low powered, and only very efficient speakers could be used with it for higher levels. Preferably horn-loaded.
The first Gainclone design, proposed by Thorsten Loesch (who I think invented the word Gainclone), did have three design premises, based on the 47 Labs philosophy:
1) Distance between parts was minimal.
2) Circuit was inverting, which reduced number of parts and improved distortion.
3) Used the LM3875, which might be considered a higher power version of the LM1875.
So if your load is not critical, using the 3875 could be interesting.
Not for me, as I don't like horn-loaded speakers, but I think it should be considered a very likely option for DIY.
I guess not only perceived, the My_Evo actually has more power.
Unfortunately I don't think it's possible...but I could be wrong.
1) My_Evo is SMD so circuit paths are very short too, although not minimal as in the Gaincard
2) The LM3886 in the MyRef is inverting too
3) Also the original Gaincard uses the LM3875
Sorry to hear your guess on Mario's return. Whatever happened was before my time here, but some people must have been absolute ***** to produce such results. I really don't want to sound presumptuous or jump to conclusions, but maybe there are a few folks who might want to think about mending fences - even if it doesn't prompt his return. Just my $0.02.
Hopefully if he's watching, he might consider changing his position for the benefit of us nu-bees or even feed some info through a friend.
Nuff said from me. I wasn't there. For my part - I'll just say THANKS!
Regards, Bob
Hopefully if he's watching, he might consider changing his position for the benefit of us nu-bees or even feed some info through a friend.
Nuff said from me. I wasn't there. For my part - I'll just say THANKS!
Regards, Bob
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Aren't zenners one kind of shunt regulators?
Doesn't the original Gaincard look crappy? Almost all of our first diy amplifiers look more well constructed. And we wouldn't charge that obscene amount of money. Or would we? 😀
Mick Feuerbacher Audio Projects
Is it OK to use sockets for LM318? I used sockets so that I can try different chips (for now). I am wondering if I can leave them there or should I remove the sockets before commissioning.
Leave the sockets in - it adds only ~3mm to the length of each trace, which is only ~3-4 nH of inductance. It doesn't make any difference to the inputs or output of the LM318, and very slight impact to the +/- 12V pins, which already have ~10 nH of trace + pin inductance.
In short, the convenience of the socket outweighs the small additional inductance.
Edit: Options for rolling opamps are fairly limited, for now. The only choices are NatSemi, TI and maybe LT 318.
In short, the convenience of the socket outweighs the small additional inductance.
Edit: Options for rolling opamps are fairly limited, for now. The only choices are NatSemi, TI and maybe LT 318.
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Thanks for the precise answer Siva! I have LM318 from both TI and National. I may not hear any difference but still want to try them with some A/B listening!
I have used both the TI and LM in my RevC, I found that over time I had problems with the TI, it sounded nice, but made my amp oscillate and run very hot triggering the spike protection. I went back to the LM and all was well.
PJN
PJN
snubber bypass
Hi
Just wanna know is there any possible improvement to bypass the big lytic caps in MyRefC with some film caps since power cap bypass is common in psu circuit to slow down the phase for better bass???
Hi
Just wanna know is there any possible improvement to bypass the big lytic caps in MyRefC with some film caps since power cap bypass is common in psu circuit to slow down the phase for better bass???
The large PSU filter caps are bypassed, rail-to-ground, by smaller electrolytics (100 - 330 uF) nearer the chipamp. There's no sonic improvement from bypassing the electrolytics with film caps. However, there's a rail-to-rail film cap (C4) that's important for sonics - this should preferably be an MKP type. You may bypass C4 with a smaller, high-quality film cap like a 10 nF styroflex.
I guess that must be C18 and 17 right.....btw aren't those position is is suggested to be empty ....???
linuxguru
did you bypass C4 in your MyRefC ?
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