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Sontec MEP-250EX in 2013 Equalisers (HW)
Old 15th May 2017
  #31
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Silvertone's Avatar
Quote:
Originally Posted by skanker View Post
Thanks for chiming in Silver

Thats a very sobering thought. Do you happen to know if theres a difference with regards to reliability depending on the production timeline?

If im correct these go back to the early 70's but were reintroduced in the mid 2000's. Does this have any baring with regards to component failure?
Burgess never really stopped making them. With Denny Purcell's unit I'm talking about the mid 1990's. I talked to both George and Burgess quite a bit back then.

I got each one of their stories on what happened with the parametric EQ they developed together. Even though they don't talk anymore, in talking to both of them I could still tell the respect they had/have for one another.

Both are great guys and super smart (obviously) when I comes to audio. I always wished they could settle their rift.

I love the Sontec sound but is it that great a difference from all the other parametric EQ's out there? Not IMHO. I've shot out too many other EQ's against it to be sold on "it's the only one"... I can assure in my world it is not.

YMWV

Have fun.

Silvertone Mastering
Old 15th May 2017
  #32
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Ben F's Avatar
Quote:
Originally Posted by Silvertone View Post
Burgess never really stopped making them. With Denny Purcell's unit I'm talking about the mid 1990's. I talked to both George and Burgess quite a bit back then.

I got each one of their stories on what happened with the parametric EQ they developed together. Even though they don't talk anymore, in talking to both of them I could still tell the respect they had/have for one another.

Both are great guys and super smart (obviously) when I comes to audio. I always wished they could settle their rift.

I love the Sontec sound but is it that great a difference from all the other parametric EQ's out there? Not IMHO. I've shot out too many other EQ's against it to be sold on "it's the only one"... I can assure in my world it is not.

YMWV

Have fun.

Silvertone Mastering
Well Gearslutz if full of different opinions and having the GML 9500 and the Sontec 462 here I would say they sound quite different, especially in the mids and top end. The Sontec is smoother and more musical, very organic. I would say almost unmatched, depending on what version you have.

The GML is more precise and rules in the low end, but there is no way the higher bands compare. Great if you want really clean high end.

Have used the Buzz, Maselec, Focusrite blue and still Couldn't be without the Sontec for mastering. Haven't used a Knif Soma I suspect it's very musical as well.
Old 15th May 2017
  #33
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Silvertone's Avatar
Quote:
Originally Posted by Ben F View Post
Well Gearslutz if full of different opinions and having the GML 9500 and the Sontec 462 here I would say they sound quite different, especially in the mids and top end. The Sontec is smoother and more musical, very organic. I would say almost unmatched, depending on what version you have.

The GML is more precise and rules in the low end, but there is no way the higher bands compare. Great if you want really clean high end.

Have used the Buzz, Maselec, Focusrite blue and still Couldn't be without the Sontec for mastering. Haven't used a Knif Soma I suspect it's very musical as well.
Hi Ben, My point is no one is going to be able to tell in the long run what EQ you used in the end. No one, no golden ear engineer, not a single human being on the planet.

For what it's worth the Buzz had very similar mids and top matched to the 430C when we shot it out in McNares room at Masterdisk. All the mastering engineers who heard it agreed on that... I know I will hear different from the Sontec owners here (each one has the most magical one, unlike any other...) but who cares...

Tools are tools, use the ones you like. I just like my tools to work and unfortunately Sontec have always been hit and miss. Great EQ but not the end all be all that people like to make them out to be... that's all.

So to the OP , if you have the money and time, buy one and see it it works for you... or works at all.

Have fun everyone.

Silvertone Mastering
Old 20th September 2017
  #34
Here for the gear
 

Quote:
Originally Posted by Steven Slate View Post
I've got both the 250EX and a 430C9. They share the same description:

- Very musical sounding filters
- Very ****ty build quality and reliability

We've been working on getting precise digital models of these boxes because frankly, I have little faith in their future. But couldn't live without their tone.

Cheers,
Steven
I have 250EX for a while now. EQ is glorious, but going thru audio alter the way some sparkles harmonics disappear. It might only happen on my very unit, but I wonder what could be the cause of it. When I bought it as demo unit from Vintage Kings, it was dead on arrival. Neil Burgess took care of the crack on the circuit board by the power transformer. And it is a shame that it doesn't have as transparent audio quality as my other hardware units like Manley or Rupert Neve or Elysia. If anyone can advice me what or how I could improve bypass quality of the signal path, I would be appreciated.
Old 20th September 2017
  #35
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Sontec equalisers

Quote:
Originally Posted by thagek View Post
I have 250EX for a while now.
EQ is glorious, but going thru audio alter the way some sparkles harmonics disappear.
it is a shame that it doesn't have as transparent audio quality as my other hardware units
If anyone can advice me what or how I could improve bypass quality of the signal path, I would be appreciated.
replace the 2 discrete op-amps in the signal path.
other than being somewhat unreliable, they are bandwidth restricted.
the design appears to be a "refined" version of an amplifier design borrowed from the RCA transistor manual, circa 1971.
plenty of options for replacement:
1. Quad/Eight AM10. no power revision required.
due to increased high frequency response, a small amount of capacitance compensation is necessary on the Sontec motherboard to avoid oscillation when the cut/boost pots are full CCW.
in my opinion, the sonics of the AM10 are superb, one of the best.
2. 918.
this discrete op-amp was designed in 1977 by Deane Jensen for Jack Williams of Pacific Recorders.
it is designed to be powered from bipolar 24 VDC but can easily be modified for bipolar 28 VDC operation.
or, one can revise the Sontec power supply to output bipolar 24 VDC, which may have some long term advantages.
in my opinion, the 918 has stellar mid and top end, but the low end sucks.
3. install any of the 2520 or compatible op-amps with the Sontec power revised to bipolar 15 VDC.
more hassle and reduced headroom unless you add step-up output transformers.
not what I would suggest but if you are a 2520 lover, maybe worth considering.
4. 990.
not worth discussing in polite company, both sonic and technical reasons.
Old 20th September 2017
  #36
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Ben F's Avatar
Quote:
Originally Posted by thagek View Post
I have 250EX for a while now. EQ is glorious, but going thru audio alter the way some sparkles harmonics disappear. It might only happen on my very unit, but I wonder what could be the cause of it. When I bought it as demo unit from Vintage Kings, it was dead on arrival. Neil Burgess took care of the crack on the circuit board by the power transformer. And it is a shame that it doesn't have as transparent audio quality as my other hardware units like Manley or Rupert Neve or Elysia. If anyone can advice me what or how I could improve bypass quality of the signal path, I would be appreciated.
That shouldn't happen.

Maybe you you an impedance issue as the output is unbalanced. Never heard a Sontec reduce top end.
Old 20th September 2017
  #37
Gear Addict
 

Sontec opamps use FET inputs.
According to George Massenburg replacing the opamps with bipolar input opamps is problematic...

QUOTE: "... The problem is that the Sontec was laid out for a FET-input op amp, which as you all know has zero input current. The 5534 and almost all bipolar input chips have significant input current, and the frequency pots on the EQ have to supply that current. Not to mention the output offset, which will result in a click on the in/out switch..." - GM (I am Replacing the Sontec Op Amps)

Quote:
Originally Posted by cathode View Post
replace the 2 discrete op-amps in the signal path.
other than being somewhat unreliable, they are bandwidth restricted.
the design appears to be a "refined" version of an amplifier design borrowed from the RCA transistor manual, circa 1971.
plenty of options for replacement:
1. Quad/Eight AM10. no power revision required.
due to increased high frequency response, a small amount of capacitance compensation is necessary on the Sontec motherboard to avoid oscillation when the cut/boost pots are full CCW.
in my opinion, the sonics of the AM10 are superb, one of the best.
2. 918.
this discrete op-amp was designed in 1977 by Deane Jensen for Jack Williams of Pacific Recorders.
it is designed to be powered from bipolar 24 VDC but can easily be modified for bipolar 28 VDC operation.
or, one can revise the Sontec power supply to output bipolar 24 VDC, which may have some long term advantages.
in my opinion, the 918 has stellar mid and top end, but the low end sucks.
3. install any of the 2520 or compatible op-amps with the Sontec power revised to bipolar 15 VDC.
more hassle and reduced headroom unless you add step-up output transformers.
not what I would suggest but if you are a 2520 lover, maybe worth considering.
4. 990.
not worth discussing in polite company, both sonic and technical reasons.
Old 20th September 2017
  #38
Lives for gear
 

Sontec 250ex

Quote:
Originally Posted by rowmat View Post
Sontec opamps use FET inputs.
According to George Massenburg replacing the opamps with bipolar input opamps is problematic
input transistors in early Sontec amplifiers are J 112 N channel fets.
discrete bi-polar op-amps such as the 918 or AM10 perform admirably in a 250EX.
no clicks nor pops, for 30 years.
Old 21st September 2017
  #39
Here for the gear
 

OK, op-amp. When I said it was dead on arrival, later Burgess personally contacted me and tried to troubleshoot the problem. As I open up the case I found extra chip card wrap with bubble wrap tied down with sticky tape, later I found out that it was op-amp. Anyway I kept it before I shipped it out to him. Now I look at the those 4 chips mounted on the circuit board and try to see any difference, (since I don't know how to test them anyway) they all seems identical, shinning new, but except 2 chips being sequential but the other 2 were not. So I checked the one I kept it was not next number to other but closed like two numbers away. When I replaced it with one that is totally out of sequence, I think it might be fixed. I ran tru audio hard bypass and bypass on the unit seems almost unnoticeable in quality. Thanks Cathode for suggestions, and Sontec to include extra op-amp in the case,
Old 21st September 2017
  #40
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Slug1's Avatar
I've had one since 2013. Great sounding eq. One thing I've noticed through use is that, well at least to me, it sounds better with conservative levels being fed to it. On the contrary, I found the Dangerous Bax sounded better when the signal was hotter. I know it's about distortion and headroom. But I typically have the Sontec early in the chain and fed with conservative levels ballpark +12to +18dbU RMS. I sold my Bax but liked it pushed up in the +20 range. But keeping conservative levels works best for me with the 250EX. Just my experience.
Old 21st September 2017
  #41
SEED78
Guest
I might give these a shot. Half way between the GML sound and the Sontec sound.
the DON classics
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