Hello
1. Can we use R3 = 0.22 or 0.25 ohm with Evo RevA Mod or it's too low value? I found some sources for this values. Unfortunately values like 0.3-0.47 are hard to buy for me.
2. Is it safe for Fremen edition amp to power speakers through long speaker wires (~10-12m each) without output RL-filter as in original lm3886 datasheet?
1. Can we use R3 = 0.22 or 0.25 ohm with Evo RevA Mod or it's too low value? I found some sources for this values. Unfortunately values like 0.3-0.47 are hard to buy for me.
2. Is it safe for Fremen edition amp to power speakers through long speaker wires (~10-12m each) without output RL-filter as in original lm3886 datasheet?
I would greatly appreciate some technical advice. There was a power surge here (created by my electric water heater!) which flashed my lights and silenced one channel of my preamplifier. It, or the preamp failing, also damaged one of my monoblocks. Now all I hear with no input is a very loud buzz through the speaker. The LED lights, relay clicks, and I measure only 7MV dc at the outputs, but there is no music, only a loud noise which almost sounds like there is no ground. I do not detect any physical damage. Can anyone suggest where to begin testing the circuit?
Peace,
Tom E
Peace,
Tom E
Tom,
It is intriguing, so to say.. The relay clicking, and Your measurement of the 7mV output offset would indicate that the composite feedback loop works (for sure in DC). It means all the active elements need to be OK..
On the other hand, there is no ground reference to the input signal (buzz)
All this would signal an R11 gone.. but in that case, typically, a strong DC offset is the result.. Maybe it's not totally gone, just got an elevated value (like from 1ohm to some dozen kohm..) .??
though.. this still would not exclude some of the input signal filtering through..🤔
It is intriguing, so to say.. The relay clicking, and Your measurement of the 7mV output offset would indicate that the composite feedback loop works (for sure in DC). It means all the active elements need to be OK..
On the other hand, there is no ground reference to the input signal (buzz)
All this would signal an R11 gone.. but in that case, typically, a strong DC offset is the result.. Maybe it's not totally gone, just got an elevated value (like from 1ohm to some dozen kohm..) .??
though.. this still would not exclude some of the input signal filtering through..🤔
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Interested in this - so what is the best combination to date that drops the last hint of grit and gain? My thoughts on this:
What voltage is LM318 supplied with? Has anyone tried separately powering it with a v.good linear or ultracap supply? I may well end up adopting OPA828 as suggested.
Finally, I've had very good experience with the SALIGNY Power GaN - Expensive, but it does seem to introduce any hash - I do think going offboard for the rectifier would help.
I have a build where i changed opamp (opa827) psus for ti tps7a very low noise linear ones. There is some increase in sq, but not as much as i expected.
But the amp i implemented that way was already very good sounding, without any harsh and with much grint, thanks to Dario and Joseph K higher quality suggested mods (caps, resistors, opamps, etc...)
P. S. In that build i use hexfred diodes, the best i know with a "normal" price. I am a first time/first models saligny user, they are very good but to be honest i found the best results in valve circuits psus
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