Hi guys,
I want to share with you a mod for the Danfield 716a, which is a quite faithful clone to the SSL channel dynamics section. While the circuit is almost identical to the original, there are some differences that you can change to make it sound even closer.
Not sure how many can benefit from this mod or how many Danfield units are out there.
Nonetheless I thought it was a good idea to document and share my findings here.
On top of the mods I´ve done I noticed that most of the pots have slightly different values (22k Dan instead of 25k SSL and 220k Dan instead of 250k SSL), which I haven´t corrected. It is conceivable that some of the component differences below have been chosen to compensate for that. I´m still happier now after doing all the changes even if the different pots might not give me full range.
Some changes affect the sound more than others, but I have listed them all here nonetheless.
I have made a picture of the Danfield circuit board and have encircled all the changes directly there. The part numbers relate to the original SSL schematic found here: http://www.ka-electronics.com/images/SSL/ssl_82E10.pdf
Let´s go for it!
A - probably the biggest difference in sound to the SSL. The Danfield has 4kHz lowpass filters in the sidechain, by putting two parallel 1nF caps to the R7 and R11. Just remove the caps (watch out that the terminals don´t touch afterwards). The image shows them already removed.
B - R31 is 1Meg in the original but only 270k in the Danfield. Most likely just an offset for the Gate Threshold trim
C - C9 is 6u8 in the original but 10u in the Danfield. I´m guessing this affects the gate release time.
D & E - compressor release time section C6 and R22. These are 22u and 10k in the SSL (there is an error in the schematic, displaying R22 as 1M), but 3u3 and 1M in the Danfield
F - this cap is called CT and 22p in the SSL but 10p in the Danfield. not sure if it affects the sound
G - this jumper sets the gate attack time. there is no switch on the front panel for this but you can wire one to this jumper. 2 is middle tap, connect to 3 for fast gate attack and to 1 for slow gate attack
H - this is R93 and adjusts the makeup gain. Danfield: 39k1 in reality, 56k in schematic. SSL: 68k.
I have tried 68k in the Danfield, and again it brings the makeupgain behaviour very close to the original (1dB difference).
Another option: desolder this (or make it switchable) if you want to disable makeup gain. This can be beneficial if you want to work a lot with slow attack compression, where the gain staging might be a bit difficult.
I have compared these changes to an original SSL channel dynamics section and after doing all the mods I´m now really happy with the Danfield, because it now sounds and reacts very very similar. The biggest change in sound was probably by removing the filters in the sidechain and by adapting the release times of the compressor and gate sections. The filters overemphasized the spikeyness of the sound (eg. the attack on a snare drum) and made the gate attack times react differently, to the point where there was very little difference between fast and slow attack. Also the gate threshold was harder to adjust before the mod, and the gate was more prone to produce clicky/poppy sounds, even in the release (esp. on a bass drum).
Open point:
- in some of my Danfield units the Gate sounds different than in others in the original unmodded state (more solid attack, shorter and less noisy tail). It´s not related to calibration, but I haven´t figured out why yet. I have developed the mod I´ve described above with one of my regular sounding Danfields so I´m interested to see what it´ll do to one of the different sounding ones.
- Addendum to this open point: I was able to pinpoint the difference to somewhere after the Gate Jumper (see point G)).
After doing the mods to a different sounding unit it sounded the same as a modded regular sounding one. I suspect that the electrolytic capacitor in the gate section (C9 - see point C)) was behaving differently because of age and was responsible for the difference.
Addendum 7th Feb 2017: After modifying the 9th one of my units I realized that this particular one did not have the sidechain filter caps (neither the holes for them). The citcuit board seemed to be a different version but was already called 716a. It seems to be the version that the schematic I have posted here fits to.
Cheers!
I want to share with you a mod for the Danfield 716a, which is a quite faithful clone to the SSL channel dynamics section. While the circuit is almost identical to the original, there are some differences that you can change to make it sound even closer.
Not sure how many can benefit from this mod or how many Danfield units are out there.
Nonetheless I thought it was a good idea to document and share my findings here.
On top of the mods I´ve done I noticed that most of the pots have slightly different values (22k Dan instead of 25k SSL and 220k Dan instead of 250k SSL), which I haven´t corrected. It is conceivable that some of the component differences below have been chosen to compensate for that. I´m still happier now after doing all the changes even if the different pots might not give me full range.
Some changes affect the sound more than others, but I have listed them all here nonetheless.
I have made a picture of the Danfield circuit board and have encircled all the changes directly there. The part numbers relate to the original SSL schematic found here: http://www.ka-electronics.com/images/SSL/ssl_82E10.pdf
Let´s go for it!
A - probably the biggest difference in sound to the SSL. The Danfield has 4kHz lowpass filters in the sidechain, by putting two parallel 1nF caps to the R7 and R11. Just remove the caps (watch out that the terminals don´t touch afterwards). The image shows them already removed.
B - R31 is 1Meg in the original but only 270k in the Danfield. Most likely just an offset for the Gate Threshold trim
C - C9 is 6u8 in the original but 10u in the Danfield. I´m guessing this affects the gate release time.
D & E - compressor release time section C6 and R22. These are 22u and 10k in the SSL (there is an error in the schematic, displaying R22 as 1M), but 3u3 and 1M in the Danfield
F - this cap is called CT and 22p in the SSL but 10p in the Danfield. not sure if it affects the sound
G - this jumper sets the gate attack time. there is no switch on the front panel for this but you can wire one to this jumper. 2 is middle tap, connect to 3 for fast gate attack and to 1 for slow gate attack
H - this is R93 and adjusts the makeup gain. Danfield: 39k1 in reality, 56k in schematic. SSL: 68k.
I have tried 68k in the Danfield, and again it brings the makeupgain behaviour very close to the original (1dB difference).
Another option: desolder this (or make it switchable) if you want to disable makeup gain. This can be beneficial if you want to work a lot with slow attack compression, where the gain staging might be a bit difficult.
I have compared these changes to an original SSL channel dynamics section and after doing all the mods I´m now really happy with the Danfield, because it now sounds and reacts very very similar. The biggest change in sound was probably by removing the filters in the sidechain and by adapting the release times of the compressor and gate sections. The filters overemphasized the spikeyness of the sound (eg. the attack on a snare drum) and made the gate attack times react differently, to the point where there was very little difference between fast and slow attack. Also the gate threshold was harder to adjust before the mod, and the gate was more prone to produce clicky/poppy sounds, even in the release (esp. on a bass drum).
Open point:
- in some of my Danfield units the Gate sounds different than in others in the original unmodded state (more solid attack, shorter and less noisy tail). It´s not related to calibration, but I haven´t figured out why yet. I have developed the mod I´ve described above with one of my regular sounding Danfields so I´m interested to see what it´ll do to one of the different sounding ones.
- Addendum to this open point: I was able to pinpoint the difference to somewhere after the Gate Jumper (see point G)).
After doing the mods to a different sounding unit it sounded the same as a modded regular sounding one. I suspect that the electrolytic capacitor in the gate section (C9 - see point C)) was behaving differently because of age and was responsible for the difference.
Addendum 7th Feb 2017: After modifying the 9th one of my units I realized that this particular one did not have the sidechain filter caps (neither the holes for them). The citcuit board seemed to be a different version but was already called 716a. It seems to be the version that the schematic I have posted here fits to.
Cheers!
