A more powerful transformer is not your problem.
Check the DC supply voltage at the PSU and at the amplifier. They should be identical.
Check the DC supply voltage at the PSU and at the amplifier. They should be identical.
Trasfo it's Ok
Try to check, when you can, value for each component...
maybe some mislabeled resistors or capacitor
Ciao
Marco
Try to check, when you can, value for each component...
maybe some mislabeled resistors or capacitor
Ciao
Marco
Just a few suggestions:
1. R1, R4 should preferably 1K/2W CFRs. Yours look like MOXs.
2. C4 should be an MKP or better, with short leads as mentioned earlier. K72s are great signal coupling caps, but not necessarily good for bypass.
3. The mute resistor should be 10k, if it isn't already.
4. A 10nF FKP2 is hard to beat at C7, though further experimentation is possible.
5. An FM at C9 is OK, but you should try a BG STD, BG PK, Silmic II or Nichicon KZ at that location.
6. C21 should be MKP/FKP or better - MKS/MKT will hurt sonics.
7. C6, C11 can be FMs, but try out Silmic IIs/Muse KZ/BG PK also.
8. C13 (if installed) should be a 1uF or higher polypropylene film/foil like a Sonicap Gen I or better. K72s will probably do well at this location.
9. The compensation network caps - C10, C32, etc. should be FKP2 or Silver Mica. Stay tuned for a possible upgrade from Dario.
Edit:
10. R3 should be non-magnetic/non-inductive. Go with Caddock (Ultimate BoM) or Fukushima MPC74 (my premium BoM).
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hi siva most of what you mention have been implemented in my boards already. the symptom remains, though, which's why i'm so frustrated. weeks of dedication and still broken. on the flip side, sound staging is whole lot better than the gainclone or any other amp that i heard for that matter, though. if the drive matches up to it, i can see this being that giant killer of every diy-er's dreams.
any common issue that could make 3886 run cooler and dynamics muted? the sound feels like it's being bottle necked somewhere. detail and resolution is there, mids feel rich and harmonic but everything is subdued and closed in.
any common issue that could make 3886 run cooler and dynamics muted? the sound feels like it's being bottle necked somewhere. detail and resolution is there, mids feel rich and harmonic but everything is subdued and closed in.
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The LM3886 runs very cool in a properly implemented MyRef, because it's very stable, with huge phase margin (90-100 degrees). If it runs cool, it probably means that your compensation network is OK.
Check your input source and attenuator - a 10k-25k pot is better for dynamics than higher impedance pots.
Check the rail voltages near the LM3886 - +/- 32V is close to optimal.
does that mean i can rule out the possibility of components being of wrong value?
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Recheck all component values anyway. The kit may have been correctly constituted, but parts may still have been incorrectly interchanged, etc., during assembly.
If you have access to an O-scope, try to run a frequency sweep and determine the unit's frequency response. Weak bass implies that the frequency response drops off early, or that the damping factor is really low.
taking a multimeter measurements, this is what i get
op amp pin 7: -14
pin 4: 9.7
R1,R4 resistors: same as bcmbob's. (normal?)
speaker terminals: 10mv each with input connected, -.1 each without.
also my transformer reads 23v ac when it's suppose to be 22v.
what else should i measure?
op amp pin 7: -14
pin 4: 9.7
R1,R4 resistors: same as bcmbob's. (normal?)
speaker terminals: 10mv each with input connected, -.1 each without.
also my transformer reads 23v ac when it's suppose to be 22v.
what else should i measure?
Pre- remove Opamps and measure again. Still crazy numbers? Replace zeners.
Often transformers under no or little load will offer higher voltages.
Uriah
Often transformers under no or little load will offer higher voltages.
Uriah
Uriah
I assume you are referring to ZD1 & ZD2. Could the other diodes D1 - D4 have an impact on the general voltage stability?
I assume you are referring to ZD1 & ZD2. Could the other diodes D1 - D4 have an impact on the general voltage stability?
Hi Bob,
That is extremely unlikely. It has never happened to me under any circumstance in any project. You could check voltage drop over each diode and make sure they are all the same.
Uriah
That is extremely unlikely. It has never happened to me under any circumstance in any project. You could check voltage drop over each diode and make sure they are all the same.
Uriah
in fact i replaced all the zeners within last couple days to ones in clave's ultimate bom. the polarity on them are correct. since i'm getting 2v less than i should at pin 4, could this be the indication of why my amp sounds under powered?
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oops i was reading them wrong. was measuring pin 2,5 yesterday ;P
pin 4, 7 with the op-amps in measure -12, 12v respectably, and correctly 🙂
zeners
zd1: -12,-.2mv.
zd2: 12,-.2mv.
does this mean everything's good?
pin 4, 7 with the op-amps in measure -12, 12v respectably, and correctly 🙂
zeners
zd1: -12,-.2mv.
zd2: 12,-.2mv.
does this mean everything's good?
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hm i guess then i should start juggling caps again. maybe too many silmic ii+ lack of smoothing cap is contributing to the overly soft sound?