khstudio
Well-known member
Just curious... How do these compare (Component & sound wise) to the 2520's from the GROUP Buy?
I have the second batch that aren't potted.
Thanks.
I have the second batch that aren't potted.
Thanks.
ours sound like the 2*5*2*0?
- Thread starter Mbira
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dissonantstring
Well-known member
hi kevin,
i've built the four PP2520 from Fabio's PCBs and i have a pair of the potted 2520s from Fabio's first round and they sound very close IMHO (if not exactly the same, though i have not made any comparisons on the A2 analyzer). i didn't order any of the unpotted DOAs from the second round, but i think the only thing that changed in the second round of unpotted 2520s was that Fabio used higher voltage caps IIRC.
my friend has 6 original Averill 312s and i'm going to socket the DOAs for him and try to compare the PP2520, Fabio's potted 2520 and the original API 2520s that came with his BA 312 cards (if i have the time).
regards,
grant
i've built the four PP2520 from Fabio's PCBs and i have a pair of the potted 2520s from Fabio's first round and they sound very close IMHO (if not exactly the same, though i have not made any comparisons on the A2 analyzer). i didn't order any of the unpotted DOAs from the second round, but i think the only thing that changed in the second round of unpotted 2520s was that Fabio used higher voltage caps IIRC.
my friend has 6 original Averill 312s and i'm going to socket the DOAs for him and try to compare the PP2520, Fabio's potted 2520 and the original API 2520s that came with his BA 312 cards (if i have the time).
regards,
grant
Greg
Well-known member
I have a pair of from the first potted batch in some 312s. Sound fantastic. I wish the second batch was exactly the same. 
khstudio
Well-known member
[quote author="dissonantstring"]hi kevin,
i've built the four PP2520 from Fabio's PCBs and i have a pair of the potted 2520s from Fabio's first round and they sound very close IMHO (if not exactly the same, though i have not made any comparisons on the A2 analyzer). i didn't order any of the unpotted DOAs from the second round, but i think the only thing that changed in the second round of unpotted 2520s was that Fabio used higher voltage caps IIRC.
my friend has 6 original Averill 312s and i'm going to socket the DOAs for him and try to compare the PP2520, Fabio's potted 2520 and the original API 2520s that came with his BA 312 cards (if i have the time).
regards,
grant[/quote]
That would be cool to hear :thumb:
i've built the four PP2520 from Fabio's PCBs and i have a pair of the potted 2520s from Fabio's first round and they sound very close IMHO (if not exactly the same, though i have not made any comparisons on the A2 analyzer). i didn't order any of the unpotted DOAs from the second round, but i think the only thing that changed in the second round of unpotted 2520s was that Fabio used higher voltage caps IIRC.
my friend has 6 original Averill 312s and i'm going to socket the DOAs for him and try to compare the PP2520, Fabio's potted 2520 and the original API 2520s that came with his BA 312 cards (if i have the time).
regards,
grant[/quote]
That would be cool to hear :thumb:
khstudio
Well-known member
[quote author="Greg"]I have a pair of from the first potted batch in some 312s. Sound fantastic. I wish the second batch was exactly the same. [/quote]
I wouldn't think higher voltage caps would make too much difference but I do wish they were potted.
Greg, Have put them up against the real 2520's?
I've never had a chance to hear a real one so a comparison is out of the question for me.
[/quote]I wouldn't think higher voltage caps would make too much difference but I do wish they were potted.
Greg, Have put them up against the real 2520's?
I've never had a chance to hear a real one so a comparison is out of the question for me.
Greg
Well-known member
I have compared it with a 2520 stamped "Huntington, NY." Very little difference if I remember correctly. Though not identical.
The difference between the Melcor 1731 and 2520 was not so subtle. Different midrange quality.
The difference between the Melcor 1731 and 2520 was not so subtle. Different midrange quality.
[quote author="Greg"]I have compared it with a 2520 stamped "Huntington, NY." Very little difference if I remember correctly. Though not identical.
The difference between the Melcor 1731 and 2520 was not so subtle. Different midrange quality.[/quote]
Different in what way? I have only built the Melcor so far and i really like the kind of mashed midrange. But i have some 2520 boards just waiting to be built..
The difference between the Melcor 1731 and 2520 was not so subtle. Different midrange quality.[/quote]
Different in what way? I have only built the Melcor so far and i really like the kind of mashed midrange. But i have some 2520 boards just waiting to be built..
Greg
Well-known member
I find it difficult to describe audio sometimes.
The Melcor had a midrange bloom as I guess I'd call it. It was nice. It has less top end, and the sound was less focused and "punchy." I also sometimes felt the Melcor was "grainy" compared to the 2520s, which I didn't like. But the Melcor is still a good opamp considering it cost me less the $10 in parts.
Others may feel differently, so I'd recommend trying them both yourself so you can be the judge. After all, so much of this is subjective.
The Melcor had a midrange bloom as I guess I'd call it. It was nice. It has less top end, and the sound was less focused and "punchy." I also sometimes felt the Melcor was "grainy" compared to the 2520s, which I didn't like. But the Melcor is still a good opamp considering it cost me less the $10 in parts.
Others may feel differently, so I'd recommend trying them both yourself so you can be the judge. After all, so much of this is subjective.
[quote author="Benny"]Hey flintan.
I re-soldered two of my 2520 BC today using your BOM. :thumb:
They're working perfectly. Thank you. Now I can use the Hi-Z input on my 312 without frying my 990s. :green:
Regards Benjamin[/quote]
Hey! Thats really great news. All creds to Mick. Got a redrawn schematic from him last week but I haven't had time to try it for myself. Now we have at least two people that had this working.
:thumb:
I re-soldered two of my 2520 BC today using your BOM. :thumb:
They're working perfectly. Thank you. Now I can use the Hi-Z input on my 312 without frying my 990s. :green:
Regards Benjamin[/quote]
Hey! Thats really great news. All creds to Mick. Got a redrawn schematic from him last week but I haven't had time to try it for myself. Now we have at least two people that had this working.
:thumb:
mick
Well-known member
Hi Benny, I still found that one of the output transistors (BC board) gets very hot with the HiZ input, so perhaps you could check that out see if you get the same result.
Flintan you can post that Diagram if you want, hope it helps
Mick
Flintan you can post that Diagram if you want, hope it helps
Mick
[quote author="mick"]Flintan you can post that Diagram if you want, hope it helps
Mick[/quote]
Ok, here it is:
http://web.comhem.se/linusandersson/Micksch2520BC_r1.JPG
Mick[/quote]
Ok, here it is:
http://web.comhem.se/linusandersson/Micksch2520BC_r1.JPG
[quote author="mick"]Hi Benny, I still found that one of the output transistors (BC board) gets very hot with the HiZ input, so perhaps you could check that out see if you get the same result.
Flintan you can post that Diagram if you want, hope it helps
Mick[/quote]
Hey Mick.
I used the Hi-Z very often the last days and had no problems. But I didn't really check if transistors were getting hot. I'm gonna check this soon.
Benny
Flintan you can post that Diagram if you want, hope it helps
Mick[/quote]
Hey Mick.
I used the Hi-Z very often the last days and had no problems. But I didn't really check if transistors were getting hot. I'm gonna check this soon.
Benny
[quote author="flintan"]Benny, did you connect C5 to base of Q2 (-in) as the schematic above or did you stick with the original?[/quote]
My C5 is connected to Q3. It seems to work so far. Should I connect it to the base of Q2 as in the schematic?
My C5 is connected to Q3. It seems to work so far. Should I connect it to the base of Q2 as in the schematic?
[quote author="Benny"][quote author="flintan"]Benny, did you connect C5 to base of Q2 (-in) as the schematic above or did you stick with the original?[/quote]
My C5 is connected to Q3. It seems to work so far. Should I connect it to the base of Q2 as in the schematic?[/quote]
If it's working :thumb:
I don't know, haven't built it yet, that's why i'm asking. :wink:
My C5 is connected to Q3. It seems to work so far. Should I connect it to the base of Q2 as in the schematic?[/quote]
If it's working :thumb:
I don't know, haven't built it yet, that's why i'm asking. :wink:
I have a quick question about the 2520BC. On the board, in-between R1 and R13, there is a through hole pad silk screened (-V). What should be done with this?
Also, what is going on with the R4|R5 pad?
Sorry one more. What is the extra pad for by C2+R10?
Also, what is going on with the R4|R5 pad?
Sorry one more. What is the extra pad for by C2+R10?
[quote author="Sender"]I have a quick question about the 2520BC. On the board, in-between R1 and R13, there is a through hole pad silk screened (-V). What should be done with this?
Also, what is going on with the R4|R5 pad?
Sorry one more. What is the extra pad for by C2+R10?[/quote]
1. I put in a wire bridge from the V- pad (the one between R1 and R13) to the hole next to the V- pin. Don't know if it's right, but I read about it somewhere here and it seems to work.
2. I put one 20k resistors in there. According to the schematic it looks right.
3. I soldered C2 in series with R10 and put them in there.
I hope the way I did it is correct. But I used two of those 2520BCs the last two weeks and they are still alive. :wink:
Also, what is going on with the R4|R5 pad?
Sorry one more. What is the extra pad for by C2+R10?[/quote]
1. I put in a wire bridge from the V- pad (the one between R1 and R13) to the hole next to the V- pin. Don't know if it's right, but I read about it somewhere here and it seems to work.
2. I put one 20k resistors in there. According to the schematic it looks right.
3. I soldered C2 in series with R10 and put them in there.
I hope the way I did it is correct. But I used two of those 2520BCs the last two weeks and they are still alive. :wink:
I've sifted through this thread and it seems as though a couple of minor corrections have been made to the original 2520bc schemo. I've redrawn the schemo with what I believe were the corrections and would like to know if it's "correct."
Does this look good?
Does this look good?
