The Sontec thread! <ATT. BUILDERS - C22 & C23>
- Thread starter Bauman
- Start date
Help Support GroupDIY Audio Forum:
Infernal_Death
Well-known member
My unit is ready and i already did a small test drive. However i have bad news. Both channels don't work. After all i am not too suprised as up until now this is my most complex project so far.
Before connection all together i tested each of the filter boards and the main board separate on the power supply and everything seemed fine.
After all filter boards were done i mounted everything in the case and started to wire all together (quite some work!) i fired it up.
As always at the beginning i checked for voltages. To my suprise i found that the posivite 18V rail dropped to -1V :shock: Puzzled as i was i hadn't time to think about this since the melcor on the d filter board on channel 1 was nice enough to disrupt my thoughts with some smoke. Of course i unplugged the whole thing.
After that i took the complete channel 1 filter boards out of the supply and only powered the second channel. This time voltages were ok so i guess the fault for this lies somewhere in the channel 1. Of course i suspect the melcor on the d filter board.
But the channel 2 didn't pass any audio. The audio i tried to pass was very low and distorted.
To be honest i hadn't really much time to test and finding mistakes as i first had to find a mistake in my second calrec channel which has been found and fortunately my calrec now runs. I also need to do the chassis work on the calrec (will be a bitch since i need to make holes for those small buttons).
And the big problem is that i just am knee-deep in work both from the company i work at and exams slowly knock on my door so it's time to start learning.
I just tell this as i really don't know when i will get to test more on the sontec and try to find the mistakes.
Jaakko and Fabio, now is your time to take your lost ground of the sontec race as i need a pitstop :green:
Flo
Before connection all together i tested each of the filter boards and the main board separate on the power supply and everything seemed fine.
After all filter boards were done i mounted everything in the case and started to wire all together (quite some work!) i fired it up.
As always at the beginning i checked for voltages. To my suprise i found that the posivite 18V rail dropped to -1V :shock: Puzzled as i was i hadn't time to think about this since the melcor on the d filter board on channel 1 was nice enough to disrupt my thoughts with some smoke. Of course i unplugged the whole thing.
After that i took the complete channel 1 filter boards out of the supply and only powered the second channel. This time voltages were ok so i guess the fault for this lies somewhere in the channel 1. Of course i suspect the melcor on the d filter board.
But the channel 2 didn't pass any audio. The audio i tried to pass was very low and distorted.
To be honest i hadn't really much time to test and finding mistakes as i first had to find a mistake in my second calrec channel which has been found and fortunately my calrec now runs. I also need to do the chassis work on the calrec (will be a bitch since i need to make holes for those small buttons).
And the big problem is that i just am knee-deep in work both from the company i work at and exams slowly knock on my door so it's time to start learning.
I just tell this as i really don't know when i will get to test more on the sontec and try to find the mistakes.
Jaakko and Fabio, now is your time to take your lost ground of the sontec race as i need a pitstop :green:
Flo
Hi folks!
Cool to see you all again!
Sontec clone with "+/-" mod - three positions: on(+)-off-on(-)
done at AM4 summing/ad711 filters passing now tests in the studio,
and it is great at all bells, but shelves (hf and lf)
aren't sounds as cool as they must be. (Maybe I'm too addictive
to Neve 1073 shelves?
))
The way shelves done in Neteq EQ seems to be more interesting....
But, this way, we deal with 3-way revlog pot (pair for bell, one for shelve)
or with 4 contact groups of relay....(we switch between different filters
instead of making shelf from bell at same filter).
Ideas????
Cheers,
Igor.
Cool to see you all again!
Sontec clone with "+/-" mod - three positions: on(+)-off-on(-)
done at AM4 summing/ad711 filters passing now tests in the studio,
and it is great at all bells, but shelves (hf and lf)
aren't sounds as cool as they must be. (Maybe I'm too addictive
to Neve 1073 shelves?
))The way shelves done in Neteq EQ seems to be more interesting....
But, this way, we deal with 3-way revlog pot (pair for bell, one for shelve)
or with 4 contact groups of relay....(we switch between different filters
instead of making shelf from bell at same filter).
Ideas????
Cheers,
Igor.
Infernal_Death
Well-known member
Fabio well i haven't really "tested" the opamps. I just seperatly connected each filter board with the melcors to the power supply to see if the melcors worked ok, didn't smoke and didn't get too warm. So after all melcors passed this "test". However i haven't tested if they pass audio. The sontec is the only circuit i can test them.
When i get the time my plan is to get the second channel working as it seems to have less problems than channel 1. If channel 2 is working i can use it as a reference to fix channel 1.
Just a quick question. If i connect both the level1 and level2 to feedback with a wire i can bypass all filter boards right ? Before starting to test each of the filter boards i want to make sure the amp board is working. So i want to connect a signal and see if the amp board is passing the audio without the filter boards connected.
Flo
When i get the time my plan is to get the second channel working as it seems to have less problems than channel 1. If channel 2 is working i can use it as a reference to fix channel 1.
Just a quick question. If i connect both the level1 and level2 to feedback with a wire i can bypass all filter boards right ? Before starting to test each of the filter boards i want to make sure the amp board is working. So i want to connect a signal and see if the amp board is passing the audio without the filter boards connected.
Flo
Sure!
You can do this:
1) Get 1 amp board and put some IC opamps in. Check if it passes audio ok.
2) Change 1 IC for Melcor and perform the audio test again.
If it works you just have your test gig for the opamps. Test 'em all.
3) You can put ICs on filters also to check everything else except the opamps are good.
cheers!
Fabio
You can do this:
1) Get 1 amp board and put some IC opamps in. Check if it passes audio ok.
2) Change 1 IC for Melcor and perform the audio test again.
If it works you just have your test gig for the opamps. Test 'em all.
3) You can put ICs on filters also to check everything else except the opamps are good.
cheers!
Fabio
Infernal_Death
Well-known member
No updates with my unit. I still have 1,5 weeks to go until my exams start (which will last for 2 weeks) and to be honest i really don't want to start on my sontec until all exams are finished. I simply know myself too good (no wonder since i had to spend the last 24 years with myself :green: ) because if i now start working on it my mind won't focus on learning for the exams as i always will think whats wrong with the Sontec.
Flo
Flo
chrissugar
Well-known member
OK Jaakko and Fabio, it seems that I will start to solder those 960 resistors to the rotary switches, so let the race begin.
Those who use potentiometers for the Sontecs will not count. :grin:
May the ELMA be with you! :guinness:
chrissugar
Those who use potentiometers for the Sontecs will not count. :grin:
May the ELMA be with you! :guinness:
chrissugar
chrissugar
Well-known member
Hey Jaako
24 steps level, 24 steps Q, 24steps freq.
For the freq you need Two waffers.
Total for stereo is 240+240+480=960
Not bad, huh?
Only 11 steps for Q? You are disqualified too! :grin: :grin: :grin:
The servos are OPA604 and the discrete opamps are the ones I built from Freds paper [ http://www.forsselltech.com/JFET%20Opamp.PDF ] and they work absolutely great, It is hard to imagine that the new ones are better but I supose they are or Fred would not make them. It is a pain to select all the fets but the results worth the efort. The preamps I made with them are very good.
Hey Fred, I woud like to say a big THANK YOU for this and for all your papers and schems. Learned alot by studiyng them.
chrissugar
24 steps level, 24 steps Q, 24steps freq.
For the freq you need Two waffers.
Total for stereo is 240+240+480=960
Not bad, huh?
Only 11 steps for Q? You are disqualified too! :grin: :grin: :grin:
The servos are OPA604 and the discrete opamps are the ones I built from Freds paper [ http://www.forsselltech.com/JFET%20Opamp.PDF ] and they work absolutely great, It is hard to imagine that the new ones are better but I supose they are or Fred would not make them. It is a pain to select all the fets but the results worth the efort. The preamps I made with them are very good.
Hey Fred, I woud like to say a big THANK YOU for this and for all your papers and schems. Learned alot by studiyng them.
chrissugar
G
Guest
Guest
Anybody else having probs reading the pdfs?
http://planeta.terra.com.br/servicos/thediypill/DIY_SONTEC/sontec_mep250ex.pdf
get a error message...
http://planeta.terra.com.br/servicos/thediypill/DIY_SONTEC/sontec_mep250ex.pdf
get a error message...
Great Jaakko, post some treaser pics!!!
BTW, I've found a new (and hopefully the last) home to my page. So the DIY Sontec page is now here:
http://www.thediypill.phx.com.br/diy_sontec.htm
now this direct link seems to work. If don't pls lemme know:
http://www.thediypill.phx.com.br/DIY_SONTEC/sontec_mep250ex.pdf
cheers!
Fabio
BTW, I've found a new (and hopefully the last) home to my page. So the DIY Sontec page is now here:
http://www.thediypill.phx.com.br/diy_sontec.htm
now this direct link seems to work. If don't pls lemme know:
http://www.thediypill.phx.com.br/DIY_SONTEC/sontec_mep250ex.pdf
cheers!
Fabio
chrissugar
Well-known member
"filter boards are stuffed and have been connected via wires to 2x24 Elma switches (500 wires, 1000 solder joints) .. half of the frq and q controls done, rest will be done this week."
Jaakoo!
FATAL ERROR!
WHAT A WASTE OF TIME AND ENERGY TO SOLDER THAT WIRE NEST!
If you solder resistors to the Elmas you have to use only three wires if you need a pot or two if you have a variable resistor. With those 500 wires I don't want to think about the possibility of interactions between the filters and crosstalk between channels. :green: :green: :green:
Come on Jaakko it is for mastering. :grin:
NOW BACK TO THE BENCH AND REDOO THE WHOLE THING! :wink:
chrissugar
Jaakoo!
FATAL ERROR!
WHAT A WASTE OF TIME AND ENERGY TO SOLDER THAT WIRE NEST!
If you solder resistors to the Elmas you have to use only three wires if you need a pot or two if you have a variable resistor. With those 500 wires I don't want to think about the possibility of interactions between the filters and crosstalk between channels. :green: :green: :green:
Come on Jaakko it is for mastering. :grin:
NOW BACK TO THE BENCH AND REDOO THE WHOLE THING! :wink:
chrissugar
chrissugar
Well-known member
OK Jaakko
I PARDON YOU [Amon Goeth [Touching his reflection in a mirror] - Schindler's list]
:green:
chrissugar
I PARDON YOU [Amon Goeth [Touching his reflection in a mirror] - Schindler's list]
:green:
chrissugar
TomWaterman
Well-known member
Hi people!
Cool to see progress with this - I'm re-thinking the idea of using the Melcors for this now, as I read on GM's forum that the Sontec was designed for a FET input opamp. I think the Forssell/604s are going to rock Jaakko!!
I wonder if Flo has had any joy with his melcor loaded clone?
BTW Jaakko, how have you calculated the frequency resistors? Is there a formula or something available? Are you still doing musically tuned steps?
Looking forward to seeing some pics...
Cheers Tom
Cool to see progress with this - I'm re-thinking the idea of using the Melcors for this now, as I read on GM's forum that the Sontec was designed for a FET input opamp. I think the Forssell/604s are going to rock Jaakko!!
I wonder if Flo has had any joy with his melcor loaded clone?
BTW Jaakko, how have you calculated the frequency resistors? Is there a formula or something available? Are you still doing musically tuned steps?
Looking forward to seeing some pics...
Cheers Tom
Similar threads
