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Who has the skinny on 2520 alternatives?
Old 26th June 2009
  #1
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u b k's Avatar
 

Who has the skinny on 2520 alternatives?

Now that I'm back in the land of all-analog, I'm hearing things I never did when I had a daw in the room. Most especially, I'm hearing qualities of air that have me curious what other flavors are available with a simple op-amp switch in a (new) 312.

What I would like is to get something that's a touch smoother, silkier, more laid back. Less tzzt, more sshhhh.

I suspect I may be trying to transmute a fiery latina into a demure filipina by putting different shoes on her, but I'm feeling experimental these days and figure I got nothing to lose but a few quid.

Thoughts?


Gregory Scott - ubk
.
Old 26th June 2009
  #2
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jsteiger's Avatar
DOA

UBK,

I assume you mean a new "512" not a 312?

There are many alternatives. I don't think he is selling them alone anymore but I think the Avedis 1122 is the best mate for a new, current 512c. His amp really tames down the harshness of a 512c.

I can also 2nd Scott Liebers SL-2520's. Get the "red dot" for a more vintage version. His "blue dot" will be more like what you are hearing now, but not quite.

If you feel like strapping on the soldering iron, I have a great solution. Classic Audio Products of Illinois

Peter Purpose from the Prodigy forum also has an outstanding "vintage sounding" DOA. He sells them direct. LAZ25 DISCRETE OP AMP

For what it's worth, I am literally days away from getting my new VP26 preamp out to certain individuals for evaluation. I have socketed my DOA so swapping out amps is a snap. I plan on selling my pre without an opamp. No one else does this. You know, for those cats who have a vintage 2520 or whatever. I will also have the option to add a Scott Liebers SL-2520 or a gar2520 with the unit at purchase.

My VP26 pre has all the vintage love you are looking for BTW.

best, Jeff
Old 26th June 2009
  #3
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thenoiseflower's Avatar
 

Quote:
Originally Posted by u b k View Post
Now that I'm back in the land of all-analog, I'm hearing things I never did when I had a daw in the room. Most especially, I'm hearing qualities of air that have me curious what other flavors are available with a simple op-amp switch in a (new) 312.

What I would like is to get something that's a touch smoother, silkier, more laid back. Less tzzt, more sshhhh.

I suspect I may be trying to transmute a fiery latina into a demure filipina by putting different shoes on her, but I'm feeling experimental these days and figure I got nothing to lose but a few quid.

Thoughts?


Gregory Scott - ubk
.
try to find a melville or huntinton op amp, I have a pair of huntington opamps that i switch around between 512's and 560b's ,they sound smoother, sweeter and have a slightly lower output(which is great in the pre). I think its way better.
of course you gotta find someone who will sell them.
Old 26th June 2009
  #4
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antoniosolo's Avatar
 

2520

I have several huntingtons and melvilles for sale currently. And yes, Avedis was refusing to sell to DIY's, havent heard the sl-2520 yet. I guess you can sit and a/b all day to find what suits you. My thinking was just to have true vintage would do it for my needs. I have huntingtons for mine. Anyway, let me know if you need some, they are checked out by techs before shipping. $140 per. 2503's as well $115 per, checked.
Old 26th June 2009
  #5
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dandeurloo's Avatar
Quote:
Originally Posted by skydog View Post

The RED DOT is exactly what you want. It is the best sounding 2520 for tracking out there!
Old 26th June 2009
  #6
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Kronos147's Avatar
Quote:
Originally Posted by vin-gear View Post
but I think the Avedis 1122 is the best mate for a new, current 512c. His amp really tames down the harshness of a 512c.
+1

FWIW, Avedis sold me some 1122's for my 512c's not too long ago. Maybe in January.
Old 26th June 2009
  #7
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u b k's Avatar
 

Great info gentlemen, thank you. And Jeff, I do indeed mean 'new 312'.

At the risk of being absurdly esoteric, is there a quantifiable difference between a typical Huntington and Melville?

What I'm hearing in the new 312/2520 circuit is what I would describe as 'ringing' up top, a slightly metallic quality to the overtones that make the upper presence and lower air ever so slightly hard, which is in direct contrast to my experience with old 512's that sound a good deal softer up top.

I would in no way characterize what I'm hearing as bad; the music I'm now working on is very acoustic, a soft and woody kinda vibe. I'd like the pre's to be a bit more relaxed.

Gregory Scott - ubk
.
Old 26th June 2009
  #8
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jsteiger's Avatar
312

Quote:
Originally Posted by u b k View Post
Great info gentlemen, thank you. And Jeff, I do indeed mean 'new 312'.
Ah...3124 then I presume? Is there something new out there we don't know about yet?
Old 26th June 2009
  #9
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superwack's Avatar
I'll admit I don't know much about circuit design but I was looking at the options and was wondering if the picture of the SL2520 is missing components --- it just looks much lighter than the GAR2520 and LAZ25 (fyi I am not making any judgment on quality, engineering, sound, etc... I'm just curious)
Attached Thumbnails
Who has the skinny on 2520 alternatives?-2520_21w.jpg   Who has the skinny on 2520 alternatives?-gar2520-front-angle.jpg   Who has the skinny on 2520 alternatives?-laz25.jpg  
Old 26th June 2009
  #10
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Quote:
Originally Posted by u b k View Post
What I would like is to get something that's a touch smoother, silkier, more laid back.
If that doesn't describe the Avedis 1122, I don't know what does.

The SL2520 uses surface mount parts which is why it looks sparce compared to the through hole versions.
Old 26th June 2009
  #11
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u b k's Avatar
 

Ah, sorry about that, it's the A2D. So it'd also be nice to get a smooth flavor for the line inputs; currently, the insert is what I use for program material, because it's a sraight wire connect to the a/d section. But the option of a color I like on the line ins would be a massive bonus.


Gregory Scott - ubk
Old 26th June 2009
  #12
TRW
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Scott Liebers has a lot of the small signal/current source transistors as surface mount.

So they are there just a lot smaller. Big devices for the push pull output - they get hotter and looks like his diff. long tail pair? I guess for matching purposes.

All of these opamps are great!

Greg, although not a direct swap, and not a 2520, you may dig a Purple KDJ-4 for smooth!

-T
Old 26th June 2009
  #13
TRW
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TRW's Avatar
Oh in an A2D.. not sure where they are in the circuit but I don't think I'd stray too far from the 2520 camp unless I knew exactly where and what its doing.

-T
Old 26th June 2009
  #14
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superwack's Avatar
thanks for the info
Old 26th June 2009
  #15
The SCA guy sells a few different op-amp designs to go into his pre-amps.
Old 26th June 2009
  #16
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jsteiger's Avatar
DOA's

Quote:
Originally Posted by superwack View Post
I'll admit I don't know much about circuit design but I was looking at the options and was wondering if the picture of the SL2520 is missing components --- it just looks much lighter than the GAR2520 and LAZ25 (fyi I am not making any judgment on quality, engineering, sound, etc... I'm just curious)
Well, at first look maybe, but I do believe Scott's amp's are of the 10 transistor design as is the Laz25. Gary's is intentionally a 9 transistor design. We could go on about when this all changed in the API history. Old lit says one thing...people who have actually dissected these old 2520's say another. Who knows for sure.

One thing I will guess, is that if you were to open up a current day production 2520, you would also find all surface mount components! I could be wrong. Someone out there has been inside. Speak up!

You can only assume it is for mass production and cost reasons.

I do know that Scott hand assembles his DOA's himself. I believe he has chosen partial surface mount components because it is very had to figure out what the hell they are...unless you really know surface mount stuff, which I sure as hell don't!

Cheers, Jeff
Old 26th June 2009
  #17
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API

My transactions with studio owners from all over finds every one of them seeking original 2520's to stay original for retaining the vintage sound and resale value. It would be fun to play with a pair of clones to see what they have to offer though.......
Old 26th June 2009
  #18
Gear Head
 

Jeff is correct. My SL-2520 is a 10 transistor version just like the coveted vintage ones as well as the new ones. I am using surface mount transistors for all the inter-stage. The diff-pair is through-hole for matching purposes. SMT parts would be too hard to test in a jig in order to match them. The output transistors are also through-hole as they need to be able to handle some current drive and heat dissipation (Although, my 2510 version handles this quite well with larger SMT output transistors).
I've dissected most of the flavors out there including the vintage and modern ones, and yes, the new ones do use some SMT parts as well.
Why did I use SMT? It was a design choice based on fitting everything on the board, using parts that are and will be available in the future, and ease/speed of assembly. I can solder SMT components by hand much faster than I can the through-hole. I've also found SMT parts easier to remove if a repair is ever needed.
I also decided to not pot my amps in epoxy. I think it's a shame to have to throw a discrete opamp away just because an otherwise replaceable part went bad.

Scott
Old 27th June 2009
  #19
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BradM's Avatar
I have some Fabio 2520's (purchased a few years ago from GroupDIY), and Avedis 1122 that I have compared directly to new API 2520's. The Fabio op amp is very very similar to the API, but with an ever so slightly more forward sounding midrange. It makes snares and kick punch just a hair more. The Avedis on the other hand is silky and smooth and sounds less agressive especially in the upper mids. Greg--you would really like these. I have a DIY 4-channel 312 that I built and it's loaded with Avedis op amp. Sounds killer.

I'm hoping to check out some of the SL-2520's in the very near future when I build some API style EQ's.

Brad
Attached Thumbnails
Who has the skinny on 2520 alternatives?-011.jpg  
Old 27th June 2009
  #20
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gar381's Avatar
 

Like Jeff says, my gar2520 DOA is intentionally a 9-transistor design based on the early Huntington.
I am trying to emulate API’s mid 70s sound for kick, snare, toms, & guitar on the
Many hit records of that period. In contrast to Scott's SL-2520 with is a wonderful sounding Product,
mine is through hole for DIY as most folks don't know how to Solder SMT parts as of yet. My offering
is designed with an assembly PDF to have a Great sounding 70s style and very stable low cost DIY
alternative to all the assembled more expensive available DOAs. I am using all currently available
easily acquired transistors which should be available for many years. I agree with Scott, non-potted
DOAs make for the easy rare repair plus the outputs cool much better than their potted alternatives.

A quick link to my kit at classicapi.com
Classic Audio Products of Illinois

GARY
Old 27th June 2009
  #21
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antoniosolo's Avatar
 

2520

DIY is a lot of fun and a learning experience. I have spoken with a few of you and know you are making possible some great recordings, which is all that counts. My pair aren't identical but utilize two different trannies and one offers switchable impedance. So far.........
Old 27th June 2009
  #22
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u b k's Avatar
 

Quote:
Originally Posted by gar381 View Post
I am trying to emulate API’s mid 70s sound for kick, snare, toms, & guitar on the Many hit records of that period.

Would you mind naming an example or two of the sound you're reaching for?

Thanks!


Gregory Scott - ubk
.
Old 27th June 2009
  #23
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by vin-gear View Post
Well, at first look maybe, but I do believe Scott's amp's are of the 10 transistor design as is the Laz25. Gary's is intentionally a 9 transistor design. We could go on about when this all changed in the API history. Old lit says one thing...people who have actually dissected these old 2520's say another. Who knows for sure.

One thing I will guess, is that if you were to open up a current day production 2520, you would also find all surface mount components! I could be wrong. Someone out there has been inside. Speak up!

You can only assume it is for mass production and cost reasons.

I do know that Scott hand assembles his DOA's himself. I believe he has chosen partial surface mount components because it is very had to figure out what the hell they are...unless you really know surface mount stuff, which I sure as hell don't!

Cheers, Jeff
I took a Newer 2520 apart awhile back(3 or so years), 100% surface mount and no mid size outputs either.

When comparing Op amps you have to consider the input/output trans as well or you will not be comparing correctly...
The idle current has a lot to do with the sound as well, from one 2520 to another I have seen the idle current to be from 5mills to 18 mills...

This is one of several tests I would perform on ALL new 2520's I got from API...
Old 28th June 2009
  #24
Gear Head
 
gar381's Avatar
 

Gregory

The sound I'm looking for in a Pre/DOA is a big fat forward edge in the mix
with out being too loud or the loudest thing in the mix. I think my DOA will give you
that effect with the right iron. 990s with Jensen Iron is wonderful for a lot of things
(Chamber music, Symphonies etc) but much to clean in my opinion for sound of classic R & R. I want to hear more edge on puncher instruments.
This is a problem with modern digital recording at any sample rate...
To clean, to sterile, no warmth, no edge.. maybe nice to some ears but to mine just boring. I am a 60 year old fart who is stuck in the old ways of doing things but
From my experience vintage API and tape compression give what my ears are looking for.... BALLS !! Where would the Eagles, Fleetwood Mac or the
Smashing Pumpkins be with out vintage API ??

GARY
Old 28th June 2009
  #25
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jsteiger's Avatar
DOA's

Quote:
Originally Posted by u b k View Post
Would you mind naming an example or two of the sound you're reaching for?

Thanks!


Gregory Scott - ubk
.
Hey UBK,

How about I see if I can get Gary to send you a fully assembled gar2520? You can drop her into 1 channel of your A2D and easily do a side by side comparison. I would assume that the DOA's are soldered directly to the PCB, not using the wonderful sockets...so some desoldering would be involved.

Would be interesting to hear your thoughts. Like a mini review? I also have a few of Scott's SL-2520 Red Dot's on hand.

Quote:
At the risk of being absurdly esoteric, is there a quantifiable difference between a typical Huntington and Melville?
This is an interesting question. I'm sure someone out there knows for sure. Everything I have is labeled Huntington.

The lit that is from the Huntington era says that the 2520 design is a "nine transistor amplifier". People I know who have dissected Huntington labeled DOA's always find 10 transistors. I remember Peter Purpose telling me that his first reverse work was done on a Melville amp. Gary's amp is based on Peter's work, hence, a 9 transistor amp. Although, if you look, Peter's current amp he makes is a 10 transistor version.

It's just a guess but the Melville/Huntington labels were just that...labels. I would gather that this in no way coincides with the 9-10 change. It may not even coincide with when they actually moved! Remember, they used 550a marked faceplates for the a-1's because they still had them. Why throw them out? Same with the opamp labels?

Also, I heard that Studio Systems ran concurrently with the Melville and Huntington versions.

This makes my head spin...

Jeff
Old 28th June 2009
  #26
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Hey Greg, I don't know if someone's already mentioned this, and I don't even know if the qualities and properties you mentioned are associated with this unit, but have you tried Tim's SC25? He owns Seventh Circle Audio and I've heard his J99 which is a descendant of the Jensen 990 unit and it sounded amazing. Again, you're looking for 'smoother' and a few other characteristics that I don't know that the SC25 posesses, especially since I think it's supposed to be a copy of API's 2520. I will say that I also have a friend who owns 512's, has 4 A12's by Seventh Circle and has 2 units with the 2520 and 2 SC25's. He picks and chooses which he uses for certain sources and my understanding from what I've seen him pick for certain sources is that he likes them on OH's, acoustic instruments and things that, to me, would require a smoother character to them. He uses the pres with 2520's on guitars and sources that I feel need a little more edge or bite. Don't know if that helps, but I thought I'd throw that in there.
Old 29th June 2009
  #27
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dandeurloo's Avatar
Quote:
Originally Posted by Slikjmuzik View Post
Hey Greg, I don't know if someone's already mentioned this, and I don't even know if the qualities and properties you mentioned are associated with this unit, but have you tried Tim's SC25? He owns Seventh Circle Audio and I've heard his J99 which is a descendant of the Jensen 990 unit and it sounded amazing. Again, you're looking for 'smoother' and a few other characteristics that I don't know that the SC25 posesses, especially since I think it's supposed to be a copy of API's 2520. I will say that I also have a friend who owns 512's, has 4 A12's by Seventh Circle and has 2 units with the 2520 and 2 SC25's. He picks and chooses which he uses for certain sources and my understanding from what I've seen him pick for certain sources is that he likes them on OH's, acoustic instruments and things that, to me, would require a smoother character to them. He uses the pres with 2520's on guitars and sources that I feel need a little more edge or bite. Don't know if that helps, but I thought I'd throw that in there.

I have the SCA pres. They are amazing. And they are a lot better once I replaced my Op amps with the Scott Liebers Op amps and an actual 990 from John Hardy . I have 4 A12's. I had two original API's from the 80's in them for awhile and I sold those and the SCA op amps that came with the units and replaced them with 2 Red Dots ( use for tracking) and 2 Blue Dots (for summing through Folcrom). I'm gonna get a few more Pres that I can just leave with Blue Dots for summing and replace the other op amps with the Red Dots. I love them. They really warm up and smooth out a vocal and drums but still have that API forward sound.

The SL Op amps hands down beat out the origianal 80's API (these are much closer to the blue dots) and the SCA and A few others that i tried. I have since had a number of friends get the red dots as well. It is a plug a play upgrade!

UBK, knowing what you like from how cool the UBK Fatso sounds you would probably really dig the SL Red Dots.
Old 29th June 2009
  #28
Lives for gear
Quote:
Originally Posted by u b k View Post
Now that I'm back in the land of all-analog, I'm hearing things I never did when I had a daw in the room. Most especially, I'm hearing qualities of air that have me curious what other flavors are available with a simple op-amp switch in a (new) 312.

What I would like is to get something that's a touch smoother, silkier, more laid back. Less tzzt, more sshhhh.

I suspect I may be trying to transmute a fiery latina into a demure filipina by putting different shoes on her, but I'm feeling experimental these days and figure I got nothing to lose but a few quid.

Thoughts?


Gregory Scott - ubk
.

LAZ25 DISCRETE OP AMP
Old 29th June 2009
  #29
Gear Guru
 
u b k's Avatar
 

Quote:
Originally Posted by vin-gear View Post
How about I see if I can get Gary to send you a fully assembled gar2520? You can drop her into 1 channel of your A2D and easily do a side by side comparison. I would assume that the DOA's are soldered directly to the PCB, not using the wonderful sockets...so some desoldering would be involved.

Would be interesting to hear your thoughts. Like a mini review? I also have a few of Scott's SL-2520 Red Dot's on hand.

Jeff,

I would love to test these various op-amps side by side and post a review here, I'd include some clips too so people could hear for themselves. I get great drum sounds here, single r84 over the kit, a 100% phase coherent full freq track that reveals all the tonal nuances of a pre. I can also do vox on a vintage ldd, that'll show up the texture of the mids and presence, and tightness of the low mids too.

The 312's in the A2D have a modern Jensen-ish input trafo on them, it's pretty clean. I'm curious to see how much the op-amp will shift the tone of the circuit. BTW, the DOA's are socketed in so swapping one out is a 10 second affair.

This is an open invite for any designer or diy'er who's curious what their op-amp will sound like in a semi-controlled but informal comparitive test.

Bring it!


Gregory Scott - ubk
.
Old 29th June 2009
  #30
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jsteiger's Avatar
It's on!!!

Quote:
Originally Posted by u b k View Post
I would love to test these various op-amps side by side and post a review here, I'd include some clips too so people could hear for themselves...
Excellent. This will be fun!

Quote:
...BTW, the DOA's are socketed in so swapping one out is a 10 second affair.
This will makes things super easy for you.

We (Prodigy) have a Lab member [silent:arts], in Germany who is currently doing some extensive Audio Precision testing on about a dozen various DOA's. He has noticed that most of the DOA's seems to settle in and stabilize after being under power for about 30 minutes. I'm not sure if this is always something that can be heard, but it can be seen in his tests.

Anyhow, I can be responsible for getting you the following:
(2) Scott Lieber's SL-2520 red dots (red is the "vintage" version)
(2) Gary Barnett's gar2520's
(2) Vintage Huntington's...we need a benchmark right? (I for sure want them back!)
(2) of my VP26 pre's...if you want and if you have a 500 rack handy. These will sound quite different than your A2D pres.

I will send Peter Purpose a note and link this thread. I only have 1 of his amps in my possession right now. He may be inclined to get you a pair for listening tests. It will be worth it. His version is fantastic.

Send me an email and we'll get this underway.

jsteiger1965 @ yahoo . com

Cheers!
Jeff
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