The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Best drop in upgrade for NE5534AP opamp? Effects Pedals, Units & Accessories
Old 22nd November 2011
  #61
Gear Head
 

Hey Jim,

I recently purchased a 28 channel Amek Angela blueface, I have seen a lot of posts from you in regards to this console. I am currently completely restoring the console and am wondering if you still upgrade the master modules, if so id like to get mine out to you. I was also wondering if that includes balancing the outputs of the module, I would like to have the master and monitor outs balanced. I was looking at the JLM site, they have some cards you can buy that do unbalanced to balanced,I was thinking of just using some of those cards and tapping into my power rails to power them.
Old 7th March 2018
  #62
Here for the gear
 
conroy's Avatar
Quote:
Originally Posted by dickiefunk View Post
To be honest I know very little about electonics which is why I'm asking for peoples expertise and experience.

Chad Kelly from Presonus owns lots of their preamps (Eureka's, MP80's and VXP's).
He has had considerable years of experience modding all of these and says that the LT1357, AD797ANZ and OPA627BP opamps work in these preamps without tweaks to the circuits!?

From his experience the LT1357 is the quietest but can sound sterile. The AD797ANZ is pretty much on par with the LT1357's noise but sounds more musical.
I have to agree with this. The LT1357 and AD797 are definite improvements over the stock op amps in the Presonus MP20.

The LT1357 is the quieter in terms of noise. It's very revealing. More detail, attack and articulation. The dynamics seem to swoon larger than life. There is an extended frequency response.

The AD797 has a warmer sound. The frequency response seems slightly narrower. I would prefer listening to this op amp for long periods of time. It's more musical and rhythmically compelling
Old 14th March 2018
  #63
Lives for gear
 

Since this thread has been revived from the dead, I'll share what I've learned about 5534 replacements in the meantime.

A new 5534 was always a subjective improvement to a vintage 5534 in our tests.

I've tried around 50 substitutes in listening/electrical tests and keep coming back to the LT1357 as a default drop in replacement. It is incredibly clean and dynamic. I would describe it as sounding like wire. It it incredibly stable, extremely low DC offset, uses next to 0 power, and puts off little to no heat. However, it is transparent enough that it might reveal other parts of your chain/equipment that you don't like.

In the single case where the LT1357 was unstable, the LME49710 worked well. It doesn't sound as clean, but its nearly there. I would guess it would be more agreeable in budget equipment.

The best sounding op amp I tried was the THS4051, but they require adapters, have high power consumption, put off tons of heat (sometimes requiring a heatsink), are not especially stable, and are thus unsuitable for most circuits.

The majority of others are interesting in terms of coloring the sound, but that was not what I was after. My favorite colored one was the old fashioned TL071.
Old 14th March 2018
  #64
Lives for gear
 

Hi
Unfortunately your tests are ONLY valid for the specific circuit designs where you fitted them. If you change the feedback components, loading and a host of other parameters your findings will be different in many cases.
Granted in places your findings will be upheld but EVERY different design must be taken independently.

I have not read the whole thread but please say which gear you tried them in and which sections of that gear.

Matt S
Old 14th March 2018
  #65
Gear Nut
 

Quote:
Originally Posted by Matt Syson View Post
.....
I have not read the whole thread but please say which gear you tried them in and which sections of that gear.

Matt S
And I thought (from the OP) that this thread is about the Presonus Eureka:

Quote:
Originally Posted by dickiefunk View Post
Hi,

I'm looking to upgrade the NE5534AP opamps in my Presonus Eureka.....
Old 14th March 2018
  #66
Lives for gear
 

Hi
While the OP was about the Presonus the thread has been all over the place on it's way here, 8 years later.
Those that have tried alternatives have not said whether it was ALL instances of the 5534 or some of them.
The issue of 'noise' is dependent on the circuit's other components as much as the op amp. The 5534 is good as a line output driver, where it does not have much gain applied and cheap to replace if accidents occur.
The comment early on about a particular chip 'lowering the lows' is of course nonsense as all the op amps have gains of well over 100dB from DC to tens of KHz at least so the frequency response will be determined by the passive components around it, this is what negative feedback does.
Matt S
Old 14th March 2018
  #67
Lives for gear
 
nosebleedaudio's Avatar
 

If someone wants 100% proof that the "Design & layout" of the PCB & grounding has a HUGE impact on the performance of gear should drop by my shop..NOW....before the evidence is gone...
The Summing amp IM modifying had MORE design flaws that I have ever seen..seriously..
BUT it HAD all the "great components"; Burr Brown amps, LM317 regulators ect..No heat sink on regulators either..
Some issues (Grounding) were not just BAD but dangerous...
It kills me when people think they can just drop a good amp and regulator in somewhere and whamo ... great clean audio...

Some people should NOT try and design & build gear...
Old 14th March 2018
  #68
Lives for gear
 

Shame you are so far away as I would take you up on the offer!
Yes absolutely, design layout and grounding are all vital.
Many people think of an 'amplifier' stage in isolation but EVERY amplifier stage is a mini 'summing mixer' which takes signal from it's intended input, the local ground, coupling from the power rails, 'input' from the feedback components, which may take reference from a slightly different ground and sums them together then amplifies it. The power rails actually carry half wave rectified audio signal at some level or another.
Matt S
Old 14th March 2018
  #69
Lives for gear
 
nosebleedaudio's Avatar
 

Quote:
Originally Posted by Matt Syson View Post
Shame you are so far away as I would take you up on the offer!
Yes absolutely, design layout and grounding are all vital.
Many people think of an 'amplifier' stage in isolation but EVERY amplifier stage is a mini 'summing mixer' which takes signal from it's intended input, the local ground, coupling from the power rails, 'input' from the feedback components, which may take reference from a slightly different ground and sums them together then amplifies it. The power rails actually carry half wave rectified audio signal at some level or another.
Matt S
I can assure you IM NOT being Dramatic or exaggerating..
They for some reason used Red for neg and Black for positive on a Bi-Polar supply...
The ground on the power supply was NOT connected but forced thru the chassis ground... Unbelievable
The 120V power lamp got its power from the chassis ground instead of the AC neutral like it should have been..WOW..
Old 14th March 2018
  #70
Lives for gear
 
nosebleedaudio's Avatar
 

I have a paper written by Deane Jensen from the early 80's that states very clearly the MA332 is a "Selected/Tested" 5534..
The MA332 DOES have the external cap (Pin 5 & 8) IF you choose not to use it..Fine..
I still have a Spec sheet for the MA332 dated 1981...The first ones I bought in the 80's was from Jensen Transformers..I believe they were like $9.00 ea..
Old 17th March 2018
  #71
I have a bunch of those old Analog Systems Raytheon 5534's (MA332 remarked) and MA362's too. They are weak next to modern designs. The TI THS4011/12 is a beast and low noise compared to the THS4051. The THS fet opamp is also quite good. The ADA 4898-1/2 is close to a perfect IC opamp.

Those Presonus mic pre's were designed by Jensen and they designed that special input mic transformer for it. Bean counters at Presonus switched brands after the first runs. One will still need to address and change the surface mount quad opamp used for the insert send/return plus the 5532 used for the balanced outputs. I like the LME49740MA or OPA1604 for the quads and the LM6172 for the balanced outs, those drive 150 ohm loads with ease. The LT1359 quad is 16 pins so I don't know if it would fit for the insert opamp.
Old 17th March 2018
  #72
Gear Nut
 

....and I always thought, that there is a dual-JFET in front of the "input"-opamp(s) of the PreSonus Eureka:
Laup Engineering
Old 17th March 2018
  #73
Lives for gear
 

Hi
Having an instrument input with (it appears) no input overvoltage protection of EMI/RF filtering seems rather reckless.
Old 17th March 2018
  #74
Quote:
Originally Posted by analogguru View Post
....and I always thought, that there is a dual-JFET in front of the "input"-opamp(s) of the PreSonus Eureka:
Laup Engineering
There is and it's run rather rich with a heatsink. They fail often. That 1/8 ratio Jensen JT-110K-HPC mic transformer was designed for that fet input circuit. That's why the secondary doesn't change the opamp response that much.

There isn't the typical rf clamps on the fet inputs as fets don't rectify rf like a bipolar transistor can. Jensen knew what they were doing.
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Similar Threads
Thread
Thread Starter / Forum
Replies
matthias / Geekslutz forum
21
Jim vanBergen / Geekslutz forum
28
jackinthebox / Geekslutz forum
0
billzoe / So much gear, so little time
3
Led / Geekslutz forum
4

Forum Jump
Forum Jump