"Yuanjing" Gainclone 3886 - eBay amazing value ?

[skodaboy]

HI all
got the opa2134 installed on one channel I know this is very well regarded . I couldn't tell much difference but then i havnt done much critical listening for a while .perhaps more detail such as fingertaps on the body of some acoustic guitar had more reverb/air to the decay of the sound.May leve the ne5532 on as this will be woofer amp in a three way.I think the input cap change to 4.7uf makes a bigger difference.Dont seem to be able to get carbon comp resistor here in Oz.might have to ebay from usa.

[linuxguru]

Originally Posted by skodaboy

got the opa2134 installed on one channel I know this is very well regarded . I couldn't tell much difference but then i havnt done much critical listening for a while .perhaps more detail such as fingertaps on the body of some acoustic guitar had more reverb/air to the decay of the sound.

Try the LM3886-side lifted-ground mod (the last one) - a clean ground makes a huge difference to detail and transparency, especially with premium op-amps. Without a clean ground, the NE5532 sounds as good or better than almost every other opamp. The only downside to the said mod is that the output offset has jumped from 0.3/0.5 mV to something like 90/130 mV, which I can live with.

May leve the ne5532 on as this will be woofer amp in a three way.I think the input cap change to 4.7uf makes a bigger difference.Dont seem to be able to get carbon comp resistor here in Oz.might have to ebay from usa.

For a woofer amp, no further mods (except the input ground lift and larger input cap) are necessary. The carbon-composition is optional - you may get a similar improvement in sonics by using just about any low-inductance resistor, like a metal-oxide or similar. Perhaps the higher value (27k or 33k) actually plays the important role. Carbon-comps also have a voltage-dependent resistance effect, but it probably isn't important at low swings.

[skodaboy]

thanks linux
ill leave as I think.Ive got another on its way which I was going to use for tweeters with poss the maura penasa rev c for mid.or should i just stick with 3 of the same?

[linuxguru]

The fully-modded gainclone with better opamps sounds sublime in the mids and highs - you can use maybe just one for the mid-range and tweeter combined, with a simple capacitive crossover for the tweeter. The Mauro Rev C is an even better candidate for this, but the current group buy may be expensive.

[skodaboy]

I was planning for ESP electronic 3 way crossovers.The cost of a decent passive 3 way crossover($100 plus) started me off on the active path.I dont think the active boards will be any more expensive!

[bcarpman]

Wow, I can't believe I'm not the only one getting entertainment out of this cheap amp board!!

Linux, can you recommend the best/cleanest way to bypass the NE5532 in the YaunJing board? I know I don't need the extra gain (is actually detrimental in my case). If you were looking to get as clean of sound out of this cheap board without really putting any $$$ into it, which mods would you make? I'm not really worried about bass output, as I'll be running a sub with a separate amp.

Great stuff guys!!!

[linuxguru]

Originally Posted by bcarpman

Linux, can you recommend the best/cleanest way to bypass the NE5532 in the YaunJing board? I know I don't need the extra gain (is actually detrimental in my case). If you were looking to get as clean of sound out of this cheap board without really putting any $$$ into it, which mods would you make?

If you're bypassing the op-amp, then it will probably sound OK, but not great, without any mods.

However, it would help to isolate the signal ground for the LM3886 input shunt resistor and feedback network from the ground plane around it (which carries large return currents from the speaker), and jumper it to a ground section which doesn't experience significant ground-bounce. A good candidate for that is the section of the ground adjacent to the op-amp.

(Edit: mods for this to be detailed later.)

Optional:

1) Upgrade the Wimas to (preferably larger valued) MKP or similar input-coupling caps.
2) Try carbon-composition resistors for the input shunt resistor as well as feedback resistor of the LM3886. I got good results with 27k, 1/4 W Allen-Bradleys at both locations.

[bcarpman]

Originally Posted by linuxguru

If you're bypassing the op-amp, then it will probably sound OK, but not great, without any mods.

However, it would help to isolate the signal ground for the LM3886 input shunt resistor and feedback network from the ground plane around it (which carries large return currents from the speaker), and jumper it to a ground section which doesn't experience significant ground-bounce. A good candidate for that is the section of the ground adjacent to the op-amp.

(Edit: mods for this to be detailed later.)

Optional:

1) Upgrade the Wimas to (preferably larger valued) MKP or similar input-coupling caps.
2) Try carbon-composition resistors for the input shunt resistor as well as feedback resistor of the LM3886. I got good results with 27k, 1/4 W Allen-Bradleys at both locations.

I look forward to your detailed mods. Any specific recommendations on bypassing the op-amp? I know that may seem obvious, and there is of course several places that look obvious to me, but I'm assuming there are probably good ways to do it and better ways.

Thanks MUCH!!!

[bcarpman]

Linux, I bypassed the buffer by just wiring into the existing wifa and removing the NE5532's and it's still not the quietest amp. I'm looking forward to any details you come up with on isolating the input ground. I know you detailed the proceedure for use with the similar board along with the input buffer mod but I'd love to see specifics without the buffer.

Any recommendations for a source for replacement input caps, as well as supply decoupling caps to solder directly to the amp power pins? Seems everyone has their favorit caps for those uses, and a google provides so many options it's dizzying.

[skodaboy]

why dont you try all the mods with buffer on one channel and compare to bypassing it on the other. linuxguru reckons performance is best with all the mods and op amp intact. im going to try carbon resistor mod and second lifted ground mod.ill then try opa2164 opamps again.