Neal, if I have my 10,000 uF's within two inches of the LM338's, can I put this 0.47 uF bypass cap across the lugs of the 10,000 uF's (instead of on the regulator PCB)?
Hi Nuuk, possibly, but I would wire it directly to the Reg to be sure. Unless you can check with a 'scope I would stick with placing it on the reg.
if you are going to regulate the OPA627
why not use a decent low-noise regulator pair like the LT1763/LT1964 from Linear if you are going to regulate the OPA627 input buffer? These are much quieter than the 78LXX 79LXX series, you can use smaller output capacitors, like 1nF instead of 20uF which is shown in your schematic. I have used them (the Linear tech regulators) as post-regulators in my small switching supplies and they work very well indeed.
why not use a decent low-noise regulator pair like the LT1763/LT1964 from Linear if you are going to regulate the OPA627 input buffer? These are much quieter than the 78LXX 79LXX series, you can use smaller output capacitors, like 1nF instead of 20uF which is shown in your schematic. I have used them (the Linear tech regulators) as post-regulators in my small switching supplies and they work very well indeed.
Re: Carlosfm BIGC
Just a correction: Rout is two 0.47ohm/3w carbon (or film) in parallel.
That makes 0.235ohms, 6 watts.
This is the ideal value after many tests, the amp this way is much less picky with cables, use what you want.
Works better than zobels.
Bob03 said:
Just a correction: Rout is two 0.47ohm/3w carbon (or film) in parallel.
That makes 0.235ohms, 6 watts.
This is the ideal value after many tests, the amp this way is much less picky with cables, use what you want.
Works better than zobels.
tbla said:
Actually my OPA627s are on the LM3886 PCB, near the chip.
As the PSU that connects to the PCB is regulatd with adjustable regs (LM338), what I have here now is double regulation for the OPA627s.😎
Anyway, you can use fixed or adj. regulators here, the voltage has to go down from around +/- 30v to +/-15~18v.
I don't feel there's much advantage in using separate trafo/psu for the buffer.
Re: Carlosfm BIGC_rev1
Let's make it clear: 0.22/5~6watt should be ok, as long as you don't use bobinated resistors.
I had better results going a little higher.
So, at the time, my 2*5m runs of Kimber 4TC started to really sing with the GC with 2//0.47 ohms, carbon 3w resistors (this gives 6 watts total, I wouldn't use lower than 4~5 watts).
You can't get a single resistor with that 0.235 ohm value, unfortunately...
Bob03 said:
Let's make it clear: 0.22/5~6watt should be ok, as long as you don't use bobinated resistors.
I had better results going a little higher.
So, at the time, my 2*5m runs of Kimber 4TC started to really sing with the GC with 2//0.47 ohms, carbon 3w resistors (this gives 6 watts total, I wouldn't use lower than 4~5 watts).
You can't get a single resistor with that 0.235 ohm value, unfortunately...
Still no scope Neal 😉 so I'll solder them onto the LM338 pins underneath the PCB.
On the subject of scopes, somebody posted a link to a software scope but searching this forum on the subject, the opinion seems to be that these are not good enough. Any comments? 😕
Hi Guys,
I finally finished my J-fet buffered,Regulated, inverted GC this weekend.
I was actually not expecting very good results, its great to be proven wrong,the first cd I listened to
I don't believe how good this little beast sounds, its crazy.
I compared it against my minimal non inverted GC using Blackgates etc, the regulated version wipes the floor with it no contest.
So to all these people that have doubts about the buffered,regulated clone please build one first before writing it off then post your results.
Big thank you to Carlos, Pedja and Neal, its been a fun weekend plus my new clone only cost me 22 quid to build (not including the parts I already had)
Regards
Leo
I finally finished my J-fet buffered,Regulated, inverted GC this weekend.
I was actually not expecting very good results, its great to be proven wrong,the first cd I listened to
I don't believe how good this little beast sounds, its crazy.I compared it against my minimal non inverted GC using Blackgates etc, the regulated version wipes the floor with it no contest.
So to all these people that have doubts about the buffered,regulated clone please build one first before writing it off then post your results.
Big thank you to Carlos, Pedja and Neal, its been a fun weekend plus my new clone only cost me 22 quid to build (not including the parts I already had)
Regards
Leo
Nuuk said:
I think I'd go along with what you said here. Most of the software scopes that use the sound card as input hardware are cute and can be some what useful to see if signals are there or not. They are not good for any kind of caliberated measurement. I know that people try to write software to use sound cards for distortion measurments and other things but the resolution just isnt there. If you realy want to see whats going on in your circuit get a real scope and distortion meter.
Later BZ
t. said:Hi Guys,
I finally finished my J-fet buffered,Regulated, inverted GC this weekend.
I was actually not expecting very good results, its great to be proven wrong,the first cd I listened to
I compared it against my minimal non inverted GC using Blackgates etc, the regulated version wipes the floor with it no contest.
So to all these people that have doubts about the buffered,regulated clone please build one first before writing it off then post your results.
Big thank you to Carlos, Pedja and Neal, its been a fun weekend plus my new clone only cost me 22 quid to build (not including the parts I already had)
Regards
Leo
Did you sleep tonight Leo?😉
Heard all your CD collection?😀
You're right, this is much better, no matter what caps you use on the unregulated GC. What are those expensive BGs for?
Weekend update
Version 2.0 of the BIGC schematic, with some "minor" 😱 bugs corrected.😀
That crap ExpressSCH has wrong pinouts on these regulators.😱
Bob, the schematic you made is fine now😎 , and has better image resolution than mine.
I have to resize this to post here, and it looses resolution.
Here it is.
Version 2.0 of the BIGC schematic, with some "minor" 😱 bugs corrected.😀
That crap ExpressSCH has wrong pinouts on these regulators.😱
Bob, the schematic you made is fine now😎 , and has better image resolution than mine.
I have to resize this to post here, and it looses resolution.
Here it is.
Attachments
About an hours worth, I don't care though, its been a great weekendcarlosfm said:
Heard all your CD collection?😀
[/B][/QUOTE]
Almost, I still can't believe how much better the regulated Clone sounds, my standard one just didn't do it for me to be honest but this one sounds lovely
You're right, this is much better, no matter what caps you use on the unregulated GC. What are those expensive BGs for?
[/B][/QUOTE]
Those caps will be used in something else now, I'm taking my minimal GC to pieces and I'm going to use it as spares
Bob, please can you do me a favour?
On your schematic, add this comment:
"R6 can be changed for a 50k multi-turn pot to adjust DC offset".
My schematic has lowsy resolution, and no time now to make it again...
Thanks
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