Hi,
so I just got this Audiolab 8000A (series B) in awesome condition and wanted to make some improvements and replacing time consumed components. So far here is my list.
1. Replacing the 10.000uf 50v Elna PSU caps with new ones. The choice is between Mundorf Mlytic 15,000uF 63v (30 euro) or Nichicon 15,000 uF, 63 V Gold Tune (18 euro). Now I've read rave impressions on the Mundorfs. Is it really worth?
2. Replacing the 6(four+two) Elna RE2s located close to the heatsink (power section) with four 47uF 63v (???not sure this is right) and two 47uF 10v. Which brand? Elna SILMIC II 47uF 10v? Nichicon Muse ES 47uF 10V? Here they are circled red (I guess?) I'm now wondering what is the white circled cap? Any idea? Should I change that one too?
3. Is it worth replacing the TL072CP 18nV with BB OPA2134 of 8nV will it make any difference and improve sound in terms of noise/distortion/clarity?
4. Replacing the 4 x 1n4002 rectifier diodes with HEXFRED Ultrafast Soft Recovery Diodes Will this change the amplifier response delay when it's turned on (it takes almost 12 secs to be activated from when I push the puwer button). No idea where they are located, can you point out?
5. Place new RCA plugs with Neutrik NYS367-2 and speaker sockets with some gold plated ones and hard wired with silver coated copper hook-up wire. Any brand suggestion? Belden ?
6. Any suggestion on the power cord? I may try constructing my own Mogami W3104 Cable perhaps but will it be any worth?
What other caps or components are a worthwhile upgrade?
I use the CD and Phono stage. Paired with modest Wharfedale Linton 3XP speakers.
so I just got this Audiolab 8000A (series B) in awesome condition and wanted to make some improvements and replacing time consumed components. So far here is my list.
1. Replacing the 10.000uf 50v Elna PSU caps with new ones. The choice is between Mundorf Mlytic 15,000uF 63v (30 euro) or Nichicon 15,000 uF, 63 V Gold Tune (18 euro). Now I've read rave impressions on the Mundorfs. Is it really worth?
2. Replacing the 6(four+two) Elna RE2s located close to the heatsink (power section) with four 47uF 63v (???not sure this is right) and two 47uF 10v. Which brand? Elna SILMIC II 47uF 10v? Nichicon Muse ES 47uF 10V? Here they are circled red (I guess?) I'm now wondering what is the white circled cap? Any idea? Should I change that one too?
3. Is it worth replacing the TL072CP 18nV with BB OPA2134 of 8nV will it make any difference and improve sound in terms of noise/distortion/clarity?
4. Replacing the 4 x 1n4002 rectifier diodes with HEXFRED Ultrafast Soft Recovery Diodes Will this change the amplifier response delay when it's turned on (it takes almost 12 secs to be activated from when I push the puwer button). No idea where they are located, can you point out?
5. Place new RCA plugs with Neutrik NYS367-2 and speaker sockets with some gold plated ones and hard wired with silver coated copper hook-up wire. Any brand suggestion? Belden ?
6. Any suggestion on the power cord? I may try constructing my own Mogami W3104 Cable perhaps but will it be any worth?
What other caps or components are a worthwhile upgrade?
I use the CD and Phono stage. Paired with modest Wharfedale Linton 3XP speakers.
Hmmm... 🙂
I would just say this, firstly be very careful as we see so many well meaning and well intentioned upgrades and recaps go horribly wrong.
1 & 2. I'm pretty much a non believer when it comes to parts marketed specifically for 'audiophile' use and would always buy on specifications/dimensions and manufacturer reputation.
3. The TL072 is perfectly suited to its use here. It is not in the audio path but is used as a DC servo. I would leave it alone.
4. The 1N4002's I see on the diagram are simply for back emf protection and you will gain absolutely nothing by replacing them.
5. If the original sockets seem a bit of a weak point then by all means replace them as long as it can be done neatly.
6. I'm a non believer on this one as well.
Have fun 😉
I would just say this, firstly be very careful as we see so many well meaning and well intentioned upgrades and recaps go horribly wrong.
1 & 2. I'm pretty much a non believer when it comes to parts marketed specifically for 'audiophile' use and would always buy on specifications/dimensions and manufacturer reputation.
3. The TL072 is perfectly suited to its use here. It is not in the audio path but is used as a DC servo. I would leave it alone.
4. The 1N4002's I see on the diagram are simply for back emf protection and you will gain absolutely nothing by replacing them.
5. If the original sockets seem a bit of a weak point then by all means replace them as long as it can be done neatly.
6. I'm a non believer on this one as well.
Have fun 😉
Thanks for replies. Well I was just assuming time consumes some electrolytic capacitors, hence the upgrade need...
Heat issue - old caps
Hi,
I noticed my Audiolab 8000A (series 207, B) gets quite hot even in idle mode. Now does replacing 30year old caps reduces the heat produced?
Hi,
I noticed my Audiolab 8000A (series 207, B) gets quite hot even in idle mode. Now does replacing 30year old caps reduces the heat produced?
Are the capacitors getting hot ----leakage rise ?
Have you checked the bias ?
Is there slight HF oscillation ?
Have you checked the bias ?
Is there slight HF oscillation ?
No 🙂
Check the bias current. If that is OK then the amp is getting as hot as it is supposed to do.
Check the bias current. If that is OK then the amp is getting as hot as it is supposed to do.
threads merged.
You're welcome 🙂
And looking at the circuit for the 8000 it would appear the bias is 'fixed' meaning that it is factory set by means of a selection of parallel resistors rather than the more usual preset.
If any of the semiconductors in the output stage have been replaced then this setting could be way off. That said the diagram gives no indication of the required current but I would suggest it is low given the output topology, perhaps 20 to 25 milliamps in total for the parallel pair of outputs. That would generate a voltage of just 2.2 to 2.7 millivolts across each 0.22 ohm emitter resistor for each transistor.
And looking at the circuit for the 8000 it would appear the bias is 'fixed' meaning that it is factory set by means of a selection of parallel resistors rather than the more usual preset.
If any of the semiconductors in the output stage have been replaced then this setting could be way off. That said the diagram gives no indication of the required current but I would suggest it is low given the output topology, perhaps 20 to 25 milliamps in total for the parallel pair of outputs. That would generate a voltage of just 2.2 to 2.7 millivolts across each 0.22 ohm emitter resistor for each transistor.