Mine was faulty, when fixed sounded dull.
After that the RIFA PEH169 brought some life back.
And then the caps at the op-amp changed the sound more than the op amp itslef, Rubycon ZA get clear and detailled, BlackGates warmth. Room to play and choose there
Seems you can look at rectifiers there, I did not but worth it ... I guess.
Hi Ricardo, yep but soon will have my Internet cut :'(
And later back
After that the RIFA PEH169 brought some life back.
And then the caps at the op-amp changed the sound more than the op amp itslef, Rubycon ZA get clear and detailled, BlackGates warmth. Room to play and choose there
Seems you can look at rectifiers there, I did not but worth it ... I guess.
Hi Ricardo, yep but soon will have my Internet cut :'(
And later back
i didn't want to start a new thread cause i'm a new member of the forum, i have the aura evolution 100 VA II, and couple of months now, it somehow lost the bass, now fully but it's lower ( i know that this sounds funny ) tried with other speakers and the same results, a friend of mine told me that it can't just be just the amp maybe it has something to do with the cd player ( don't know how i know that this sounds funny too ), and also it has some weird sound while using the volume knob don't know what was the word for that, any help will be apprecieted
p.s. sorry for my bad english
p.s. sorry for my bad english
My problems disappeared when I resoldered almost all solder points inside the amp. The brumming problem disappeared when I resoldered the PSU board. Missing channel was more tricky. At first I restricted myself the preamp circuit ( as I still could hear some static floor noise with the amp on and sticking my ear to the spreaker of the channel that has gone; I thought the power amp section was still ok). It did not help, so I resoldered every joint. I am using the amp for a few months without any problems.
important bias info:
1. connect the AC- ampmeter to the AC powercord, connect 8Ohm loads to the LS outs
2. set the bias values to min. : "RV22 (fully ClockWise) & RV122 (fully anti ClockWise)"
- take care on writen words: my bias pots have other number (RV 1 & 2) in EVO2 - unsure if given direction to minimum is correct for every pcb Revision...
4. with bias on minimal, and no Signal, idle current should be:
24mA for 220/240Vac
48mA for 110VAC
50mA for 100VAC
5. Now open the bias trimmer:
+48mA/ch for 240VAC
+50mA/ch for 220VAC
+100mA/ch for 110VAC
+110mA/ch for 100VAC
6. do the same for channel 2
in the end, the currents are 1x idle & 2x Bias , just add the values for both channels
i would suggest to replace the black omron Relais, this seems to be underrated. I went for the yellow panasonic DS2Y-S-12 ( 250 V/AC Max. 60 W/62,5 VA)
1. connect the AC- ampmeter to the AC powercord, connect 8Ohm loads to the LS outs
2. set the bias values to min. : "RV22 (fully ClockWise) & RV122 (fully anti ClockWise)"
- take care on writen words: my bias pots have other number (RV 1 & 2) in EVO2 - unsure if given direction to minimum is correct for every pcb Revision...
4. with bias on minimal, and no Signal, idle current should be:
24mA for 220/240Vac
48mA for 110VAC
50mA for 100VAC
5. Now open the bias trimmer:
+48mA/ch for 240VAC
+50mA/ch for 220VAC
+100mA/ch for 110VAC
+110mA/ch for 100VAC
6. do the same for channel 2
in the end, the currents are 1x idle & 2x Bias , just add the values for both channels
i would suggest to replace the black omron Relais, this seems to be underrated. I went for the yellow panasonic DS2Y-S-12 ( 250 V/AC Max. 60 W/62,5 VA)
A plea for help. My Aura VA100 has performed flawlessly for 20 yrs. However, now vinyl is making a comeback I wheeled out the Dual CS505 only to find the Phono stage of the Aura has packed up. I'm reasonably handy with a circuit tester and soldering but have no idea what to look for.
Any ideas?
Any ideas?
One suggestion was to be suspicious of the source selector switch. I squirted contact cleaner in the pcb end and gave it plenty of twisting to and fro, but no luck. A few of the resistors look quite "hot" although they still give resistance readings, albeit one (R34) reads 20k rather than the expected 2k.
Hi all, since i don't have any reliable service in my town for my amp i would like to consult with some of you here about and issue i have before i go to another city and take the amp there. It's a weird issue, after an hour of listening when the amp gets warm (up to the so called operating temperature) it starts to crack pop and lose the sound from the left channel, first I thought that maybe it was a dirty pot or a loose cable connection i cleaned it checked the cables and it still happens note it only happens after hour or maybe 45 min listening on normal volumes maybe a 1/4 or 1/8 turn on the pot oh and tried it at louder volumes 1/2 and a bit more it's the same. After I started to think maybe it had something with the speaker output but then i connected a pair of headphones and the result was the same and i can say maybe worse and there was low crackling on the right barely noticeably but it was there.
So did anybody had this issue ?
What are the chances of having to replace the volume pot ?
Or maybe it's a bit more serious issue ?
I know it's a long shot asking without seeing the amp, but maybe someone with experience can point me to the right direction what could cause this.
New amp is out of the question because this amp has a sentimental value to me and it sound good (i don't know why but I don't like the sound of newer amps it sound to digital to me if it's a way to explain) I know it sounds funny but it is what it is.
I hope someone will answer and help
Thanks
So did anybody had this issue ?
What are the chances of having to replace the volume pot ?
Or maybe it's a bit more serious issue ?
I know it's a long shot asking without seeing the amp, but maybe someone with experience can point me to the right direction what could cause this.
New amp is out of the question because this amp has a sentimental value to me and it sound good (i don't know why but I don't like the sound of newer amps it sound to digital to me if it's a way to explain) I know it sounds funny but it is what it is.
I hope someone will answer and help
Thanks
Hello. Following this thread, I take the opportunity to consult, I have to repair an Aura Evolution VA100II, I couldn't find its schematic, I already went through a service and found the 2SK/2SJ replaced by IRF/IRFP, I have a lot of crossover distortion, I guess I have to reform the polarization, I do not observe temperature compensation. This is my first query, would it be feasible for it to work with these IRF/IRFP by adjusting their polarization? Another problem that I observe, or maybe it is not such, is that when it goes into hard overload, the protection is activated and it does not reconnect again, unless I cut the power about 20 seconds and turn it on again, there is no DC present in the outputs when this occurs, is this normal for this amp? The protector is implemented with 2 TL084 and an LM339, it seems to be somewhat complex, I couldn't get the circuit on paper either. Thanks in advance.
I don't think replacing lateral MOSFETs with verticals is a good idea, even if you have a solution for the increased gate threshold voltage. That's because verticals have a negative gate threshold voltage coefficient vs temperature. Which means they're prone to thermal runaway and need very good heatsinking. OTOH laterals are self-limiting.
As far as I'm aware, Exicon still makes lateral MOSFETs in plastic packages : http://www.exicon.info/
As far as I'm aware, Exicon still makes lateral MOSFETs in plastic packages : http://www.exicon.info/
Suitable replacements for 2sk1058/2sj162 for example, would be ECX10N20/ECX10P20 from Profusion PLC in the UK. They did have agencies in Europe but I don't know if any such arrangements still exist.
https://www.profusionplc.com/parts/ecx10p20
https://www.profusionplc.com/parts/ecx10n20
Subwoofer applications are tough on power amps and as abraxalito suggests above, don't try to substitute the power mosfets with common vertical types before making the necessary full and properly considered design changes to the amplifier.
https://www.profusionplc.com/parts/ecx10p20
https://www.profusionplc.com/parts/ecx10n20
Subwoofer applications are tough on power amps and as abraxalito suggests above, don't try to substitute the power mosfets with common vertical types before making the necessary full and properly considered design changes to the amplifier.
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thanks, but it's not that version, I'm talking about the MK II and I only found something partial but I'm not sure it's the same amplifier
