SONTEC anyone?

[godcity]

I've got a Sontec mep-250c that's acting up. It seems like a small problem to me, but every tech I've taken it to is either stumped or doesn't want to work on it. I cornered burgess at AES and described it to him, but it didn't sound familiar to him either.

The problem is: The left channel high mid band sounds like it has an intermittent multiplier on it. With the gain set flat, if you, for example, set the frequency at 1k and start to increase the gain, it will sound like you're boosting 5k. Once you get up to about 5db of boost, it will "pop" back to the correct frequency. When you lower the gain, it will stay at the proper frequency for a while before eventually popping back to the multiplier.

I'm hoping to find someone who's experienced with these EQ's and willing to take a look at it.

email Godcity@aol.com if you're interested or know someone who might be.

Thanks!
Kurt

[Led]

Sounds like a dodgy multiplier switch that is shorting to the wrong contact. Could be dirt in there or it could be that it is simply worn out. Is it a switch on the Sontec for the multiplier? I don't have one so I don't know but it sounds like that sort of thing.

[godcity]

sounds like that but there are no multiplier switches on an mep250c. plus, all of the freq, gain, and Q controls are continuously variable, not stepped. the only switches on the entire unit are for bypass.

Originally Posted by Led

Sounds like a dodgy multiplier switch that is shorting to the wrong contact. Could be dirt in there or it could be that it is simply worn out. Is it a switch on the Sontec for the multiplier? I don't have one so I don't know but it sounds like that sort of thing.

[thermos]

I can almost guarantee its a bad pot. The pot is either too dirty, or is losing connection, thus it doesn't know what its doing. It will make the op amps act up as well/ oscillate, pop, etc.

[drpat]

You may want to try re-flowing the solder for all of the pots. This cleared up the same type of symptoms that you are talking about with my 250B.

[Wavebourn]

The problem is, the frequency goes up, while in case of bad contact in the pot it should go down.

Some bug made a nest there?

[thermos]

Originally Posted by drpat

You may want to try re-flowing the solder for all of the pots. This cleared up the same type of symptoms that you are talking about with my 250B.

250 B? I've never seen one of those. Care to show a pic?

[drpat]

[music friend]

Wow! Having never seen this model before, I never knew the GML 8200 borrowed the look of Sontec that closely.

[thenoiseflower]

+ 3 for dirty or damaged pot.
the signal stays present and clean, just takes a second for it to take effect?
I/ve actually experienced what I though was this once with a GML EQ. From what I understand it was fixed with a replacement Freq/Q pot.

Have you asked Rob Lohr?
This is Joe one of his guys, the 2 mix still sold?

[godcity]

hi joe,
yeah, rob suggested i contact GML. GML didn't know and didn't have any good leads on Sontec techs, so off to geekslutz i went.
what's this about a 2 mix?
-kurt

Originally Posted by thenoiseflower

+ 3 for dirty or damaged pot.
the signal stays present and clean, just takes a second for it to take effect?
I/ve actually experienced what I though was this once with a GML EQ. From what I understand it was fixed with a replacement Freq/Q pot.

Have you asked Rob Lohr?
This is Joe one of his guys, the 2 mix still sold?

[thenoiseflower]

Should have re-checked spelling. Thought I typed "solid"

was meaning to say/ask if the 2 mix was still properly quiet since we left that morning.

------
IF GML couldn't help with your description of the issue, and the problem likely isn't the HS1000 op-amps (you aren't getting the usual !CRAZY! noises when operating with a bad op amp in the channel, which would be the worst) I don't know what to say other than the best(only) thing to do may be touch all the solder joints to and on the affected pot and go from there... if its still acting silly.. I would avoid any further dicking around like the plague til' you had a Sontec "guy" that can/will work on it. good luck with that .

thinking is - the next possible issue is debris got in the pot and maybe damaged the teeny little legs inside the pot, and if thats thats it, the whole micro surgery of a totally gone/unique part, makes techs VERY nervous. KWIM.

Someone besides Burgiss has to be able to look at these things by now, right -

Oh this may be a bad lead, but, try calling IAN @ BoutiqueAudio - 818 564-4051

FWIW he knows a shit load of great techs.

[godcity]

2 mix is good!

doesn't look like it would be that hard to replace the concentric gain/Q pot if i can source the right one. also, this thing is full of TL071's (not socketed of course). there's probably something better out there now i could use. i'm no EE, but my solder skills are fine, so if someone tells me what to do, i can do it.

still interested in in those chandler limiters? PM or email me.

Originally Posted by thenoiseflower

Should have re-checked spelling. Thought I typed "solid"

was meaning to say/ask if the 2 mix was still properly quiet since we left that morning.

------
IF GML couldn't help with your description of the issue, and the problem likely isn't the HS1000 op-amps (you aren't getting the usual !CRAZY! noises when operating with a bad op amp in the channel, which would be the worst) I don't know what to say other than the best(only) thing to do may be touch all the solder joints to and on the affected pot and go from there... if its still acting silly.. I would avoid any further dicking around like the plague til' you had a Sontec "guy" that can/will work on it. good luck with that .

thinking is - the next possible issue is debris got in the pot and maybe damaged the teeny little legs inside the pot, and if thats thats it, the whole micro surgery of a totally gone/unique part, makes techs VERY nervous. KWIM.

Someone besides Burgiss has to be able to look at these things by now, right -

Oh this may be a bad lead, but, try calling IAN @ BoutiqueAudio - 818 564-4051

FWIW he knows a shit load of great techs.

[Peter Simonsen]

Originally Posted by music friend

Wow! Having never seen this model before, I never knew the GML 8200 borrowed the look of Sontec that closely.

I would not say the GML 8200 "borrowed" the looks of the Sontec..I mean George more or less designed the sontec back then..so one could say he just continued the product line and the look after he started GML in 1982.

Kind regards

Peter

[Paul Gold]

The gain pot is a center tapped pot. They are impossible to find in small quantities. You can buy 100pcs from Alpha at about $15ea. The concentric frequency select and Q pot will be a dual reverse log on one shaft with a linear on the other. You might be able to get Omeg to make you some. They have a reasonable minimum order quantity.

[GRUNTBOY]

Originally Posted by music friend

Wow! Having never seen this model before, I never knew the GML 8200 borrowed the look of Sontec that closely.

'BORROWED' is a polite way to put it:)

[GRUNTBOY]

Originally Posted by godcity

I've got a Sontec mep-250c that's acting up. It seems like a small problem to me, but every tech I've taken it to is either stumped or doesn't want to work on it. I cornered burgess at AES and described it to him, but it didn't sound familiar to him either.

The problem is: The left channel high mid band sounds like it has an intermittent multiplier on it. With the gain set flat, if you, for example, set the frequency at 1k and start to increase the gain, it will sound like you're boosting 5k. Once you get up to about 5db of boost, it will "pop" back to the correct frequency. When you lower the gain, it will stay at the proper frequency for a while before eventually popping back to the multiplier.

I'm hoping to find someone who's experienced with these EQ's and willing to take a look at it.

email Godcity@aol.com if you're interested or know someone who might be.

Thanks!
Kurt

237 AM THURSDAY -

Hi Kurt, I realize that this is an old post (relatively) but I hope that you were able to resolve the issue with your 250. I am an audio tech from way back and have worked on Sontec gear with some regularity. However, failures are not actually very common and thus my experiences with this particular brand of gear is somewhat limited. I should mention that their equipment is much more reliable than it has been represented to be. It seems as though some individuals have started one or maybe more rumors which have been allowed to continue for an unduly amount of time.

Some of the replies that I read concerning possible fixes seemed fairly reasonable to try. If you have not been able to gain satisfaction please contact me an I will attempt to assist you further. I have never heard of this problem before but I am willing to give it some analysis. The pots for this unit are still available as far as I know and do not have to be specially ordered or specially made by anyone. Therefore, if you and I find that a pot is the issue then we will likely have a solution. Contacting Mr. Mac Neal should be fairly simple. Like most makers of superior audio gear he is probably working in his lab at this very moment but staying awake just a bit later than most as I have been able to reach him on numerous occasions late at night as well as during the day after about 1030 AM EST. He has always been very helpful to me in regard to solving technical problems and seems to be very dedicated. I have never encountered anyone in all these years who has disagreed about this. Perhaps this is one of the reasons why Sontec has always been the leader of the related industry instead of companies such as GML etc who only give answers when it suites them and only if it puts the money in THEIR own pockets.

[godcity]

do you have a number for burgess? the iti site seems to be down right now.
thanks
kurt

Originally Posted by GRUNTBOY

237 AM THURSDAY -

Hi Kurt, I realize that this is an old post (relatively) but I hope that you were able to resolve the issue with your 250. I am an audio tech from way back and have worked on Sontec gear with some regularity. However, failures are not actually very common and thus my experiences with this particular brand of gear is somewhat limited. I should mention that their equipment is much more reliable than it has been represented to be. It seems as though some individuals have started one or maybe more rumors which have been allowed to continue for an unduly amount of time.

Some of the replies that I read concerning possible fixes seemed fairly reasonable to try. If you have not been able to gain satisfaction please contact me an I will attempt to assist you further. I have never heard of this problem before but I am willing to give it some analysis. The pots for this unit are still available as far as I know and do not have to be specially ordered or specially made by anyone. Therefore, if you and I find that a pot is the issue then we will likely have a solution. Contacting Mr. Mac Neal should be fairly simple. Like most makers of superior audio gear he is probably working in his lab at this very moment but staying awake just a bit later than most as I have been able to reach him on numerous occasions late at night as well as during the day after about 1030 AM EST. He has always been very helpful to me in regard to solving technical problems and seems to be very dedicated. I have never encountered anyone in all these years who has disagreed about this. Perhaps this is one of the reasons why Sontec has always been the leader of the related industry instead of companies such as GML etc who only give answers when it suites them and only if it puts the money in THEIR own pockets.

[Peter Simonsen]

Originally Posted by GRUNTBOY

237 AM THURSDAY -

Hi Kurt, I realize that this is an old post (relatively) but I hope that you were able to resolve the issue with your 250. I am an audio tech from way back and have worked on Sontec gear with some regularity. However, failures are not actually very common and thus my experiences with this particular brand of gear is somewhat limited. I should mention that their equipment is much more reliable than it has been represented to be. It seems as though some individuals have started one or maybe more rumors which have been allowed to continue for an unduly amount of time.

Some of the replies that I read concerning possible fixes seemed fairly reasonable to try. If you have not been able to gain satisfaction please contact me an I will attempt to assist you further. I have never heard of this problem before but I am willing to give it some analysis. The pots for this unit are still available as far as I know and do not have to be specially ordered or specially made by anyone. Therefore, if you and I find that a pot is the issue then we will likely have a solution. Contacting Mr. Mac Neal should be fairly simple. Like most makers of superior audio gear he is probably working in his lab at this very moment but staying awake just a bit later than most as I have been able to reach him on numerous occasions late at night as well as during the day after about 1030 AM EST. He has always been very helpful to me in regard to solving technical problems and seems to be very dedicated. I have never encountered anyone in all these years who has disagreed about this. Perhaps this is one of the reasons why Sontec has always been the leader of the related industry instead of companies such as GML etc who only give answers when it suites them and only if it puts the money in THEIR own pockets.

..*LOOOL*.. B.S factor 100%

Kind regards

Peter