Sound Skulptor: Pre's, Compressors, Tape Simulator, Professionnal Audio Kits

[andow]

Do you have any sound samples of the True Grit?

 

[JPK]

Coming soon: Sound Skulptor EQ250 Stereo Parametric EQ for the 500 series.

More details in the first post.

 

[canidoit]

Coming soon: Sound Skulptor EQ250 Stereo Parametric EQ for the 500 series.

More details in the first post.

Hi JPK,

When do you think these will be available?

Can these be customised for indented knobs for recall?

You mentioned inspired, what would be the differences between the original - do you have different curves, frequencies, etc. is the sound quality the-same, or yours is cleaner, low noise?

Thank you.

 

[JPK]

The EQ250 will be available in 2-3 weeks.
The potentiometers are typical 9mm pots which do exist with detents (11, 21, 41). But they are not standard and you will probably need to purchase a large number.
The main difference with the original is in the use of modern OPA134 and OPA2134 op-amps, allowing the removal of some coupling capacitors. So IMHO same or better sound quality.

 

[fragletrollet]

Not that I know much about opamps, but weren't the opamps used in various Sontec designs extremely high fidelity, and running on quite high voltage rails?
Do you consider OPA2134 equivalent or even superior to these? What was used in the 250 originally, HS or 990 or something else?

I see companies like JLM selling modern incarnations of various of these opamps (HS ? ), and they are all very expensive, linear frequency response way into bat territory and running on +/- 24V to 30 or so. I don't question that an OPA2134 is a high fidelity product, just curious on why one would be enticed to spend 200$ on an "original" HS opamp instead.

 

[JPK]

When Sontec was launched in 1975, the best op-amps available were the TL071 and NE5534. This is probably why they preferred to build discrete op-amps for the input and output stages. Today we have the OPA134 and THAT1646 which are excellent in terms of noise, distortion and offset, even with a lower suply voltage of +/-16V.

 

[kante1603]

EQ250 built...and happy!

best regards,

Udo.

 

[canidoit]

EQ250 built...and happy!

best regards,

Udo.

Hi Kante, great to hear! Any thoughts on sound quality, does it have a transparent sound to it or does it add some color?

Are you using it for tracking, mixing or mastering duties and how are you finding it on these tasks?

Also, how did you find building it, easy paint by numbers and was calibration a breeze to get matched for mastering duties?

Thank you.

 

[kante1603]

Hi Kante, great to hear! Any thoughts on sound quality, does it have a transparent sound to it or does it add some color?

Are you using it for tracking, mixing or mastering duties and how are you finding it on these tasks?

Also, how did you find building it, easy paint by numbers and was calibration a breeze to get matched for mastering duties?

Thank you.

Hello,
for me it is a good and versatile eq,Best use is on the stereobus in my opinion,not so much in a recording chain.I did not use it too often so far simply because it is brandnew.Time will show.But what I heard from it was really pleasing,smooth and "expensive".Same as all good variations of a 250 style eq it works great on every thing in the bass area (e.g. in complex signals like music) and yes-it does "air".For mastering purposes I am used to work with ms-techniques meaning using mono versions of these eqs or others.
Having a stereo 250-style eq is a nice addition to my arsenal of course.It depends on what I want to do.Very good for shaping music and generally a very serious eq! I can really recommend it.
For more info you might want to read everything about it on the soundskulptor pages and for the build itself may I suggest to read the good "Jean-Pierre-style" assembly manual first:

https://www.soundskulptor.com/skdocs/eq250-assembly-guide-01.pdf


canidoit.....yes-I think so

Best regards,

Udo.

 

[Quantum J Audio]

Same as all good variations of a 250 style eq it works great on every thing in the bass area (e.g. in complex signals like music) and yes-it does "air".For mastering purposes I

Udo.

Soundskulptor does state this is inspired by the 250-A circuit, and it does differ in several respects quite considerably.

This circuit misses the same implementation of 6 x servo circuits of a Sontec 250A that is used to remove the DC offset. This EQ uses several additional capacitors in the signal path and the 1646 IC. The balancing circuit is implemented differently, and there is no unity gain circuit.

For critical stereo, I'd be interested to see how closely matched your EQ curves are.

This is a great design in terms of cost savings.

 

[jensenmann]

There´s no need for servos when OPA2134s are used in the filter circuit. Their bias current, offset and DC precision is so much better than with the original chips. Sontec realized the problems in their design and changed the filter circuit to DOAs in the 250EX and later even changed back to ICs (LM49720 IIRC) without servos.

 

[Quantum J Audio]

There´s no need for servos when OPA2134s are used in the filter circuit. Their bias current, offset and DC precision is so much better than with the original chips. Sontec realized the problems in their design and changed the filter circuit to DOAs in the 250EX and later even changed back to ICs (LM49720 IIRC) without servoss

So, this design is more inspired by the 250EX design rather than the original 250-A.

 

[musgrave]

Do you consider OPA2134 equivalent or even superior to these? What was used in the 250 originally, HS or 990 or something else?

Joe Gastwert and Todd Willson did many listing test between Sontec HS1000, HS1100(fet) and OPA’s at the Complex (Massenburg’s studio) they thought the OPA604 was the winner and built Jos’ mastering console with a servo implementation. I built center sections for Neve VR‘s using Massenburg‘s discreet amps and at Ocean Way Nashville in the B room, we did listening test between discreet running on 28 V and OPA 2134, OPA 134 center sections on 16 V. I built the center section so it could either run off the console power with OPA‘s or you could plug 28 V in and run discretes. Sal and I both agreed with more organic sources, the discretes sounded better and with more compressed and smoothed sources the OPA2134, 134 sounded better. Such a revelation I was paying $55 an amp in quantities of 500 and for the same quantity I was paying $2.70 for the OPA’s. When I was at Conway Studios, we built crossovers for the mains using Sontec HS 2000. Possibly my fav’s. But overtime I have been very happy with the 2134 for their stability out in the real world and the OPA 228 for my bipolar needs as they clip symmetrically and beautifully where many of the other hi-fi ones latch up momentarily on a hard clip. Again, I’m not the smartest guy in the building. I build gear to tell stories.

 

[JPK]

This EQ uses several additional capacitors in the signal path

We actually added 2 capacitors at the input to prevent DC from coming in from outside, but the low DC offset of the OPA134 allowed us to remove 2 capacitors in each filter for a total of 20!