Noob needs help with z5600a II mic repair

[Adam Frandsen]

Hi,

I tried posting this a few days ago, but I think it either got lost somehow or no one has seen it, so I am trying to repost it here

https://groupdiy.com/threads/se-electronics.84445/
"Hi - I need to make a new cable for the z5600a II, I understand the connector type is a GX20, but I am not a tech expert, so could someone link to me the cable type and connectors I need and any schematic on how the wires should be soldered...
I can see inside the PSU that the center PIN has no attachment to the PCB, I hope this is right, as I bought the mic used... Already had to replace a cap in the PSU that was blown causing a terrible hum, and can see inside the mic that several caps and resistors have been replaced. I hope this is not gonna end up costing me as much as a new mic to fix.

I also cannot find much info on the ecc83a tube, one forum mentioned it has a gain factor similar to an 12at7, but in a video on Youtube a guy from sE says its just a low noise version of ecc83...
I would also like to know, if I can put a silver mica cap rated for 500v/100pF in place of the 100JP/630v in the mic. Also the large resistor in position R5 (I believe it is) 300k has been replaced by two metal film resistors soldered together, is this a decent replacement? And a last question, most of the electrolytic caps I can find to the specs of the mic are 0.2-0.25DF, is this too high? Oh one more last question, I cannot read the pixelated text and numbers on the diagram of the PSU, not sure I would fully understand it either - but, what transfomer can I buy to upgrade/replace the one currently in the PSU." Thanks, A

 

[Whoops]

"Hi - I need to make a new cable for the z5600a II, I understand the connector type is a GX20, but I am not a tech expert, so could someone link to me the cable type and connectors I need and any schematic on how the wires should be soldered...

for the connector you just need to Google "GX20 connector"...

But there's a photo of the connector here:
https://groupdiy.com/threads/source-for-se-electronics-z5600a-tube-mic-8-pin-connector.76342/page-2
as for cable you can use Gotham GAC7 or Sommer Cable SC-Octave Tube

I can see inside the PSU that the center PIN has no attachment to the PCB, I hope this is right

You have to check it with the schematic, they you will be sure

I also cannot find much info on the ecc83a tube

Really??????
that's impossible Google brings a lot of information on the ecc83a

You need to Google more than you are doing at the moment

I would also like to know, if I can put a silver mica cap rated for 500v/100pF in place of the 100JP/630v in the mic.

500V is still much much higher than any voltage inside the mic, so yes that fine.

The question is, is it worth changing the Cap?

Also the large resistor in position R5 (I believe it is) 300k has been replaced by two metal film resistors soldered together, is this a decent replacement?

Yes.
2 Resistors soldered together (in series) act exactly like 1 resistor

And a last question, most of the electrolytic caps I can find to the specs of the mic are 0.2-0.25DF, is this too high?

It's dependent of the original caps value.
What's they're value?

What do you mean by caps to the specs of the mic?

what transfomer can I buy to upgrade/replace the one currently in the PSU."

None.
Whats the problem with the original Power transformer?
Why do you think there's anything to upgrade in the power transformer?

 

[Adam Frandsen]

for the connector you just need to Google "GX20 connector"...

But there's a photo of the connector here:
https://groupdiy.com/threads/source-for-se-electronics-z5600a-tube-mic-8-pin-connector.76342/page-2
as for cable you can use Gotham GAC7 or Sommer Cable SC-Octave Tube




You have to check it with the schematic, they you will be sure



Really??????
that's impossible Google brings a lot of information on the ecc83a

You need to Google more than you are doing at the moment



500V is still much much higher than any voltage inside the mic, so yes that fine.

The question is, is it worth changing the Cap?




Yes.
2 Resistors soldered together (in series) act exactly like 1 resistor



It's dependent of the original caps value.
What's they're value?

What do you mean by caps to the specs of the mic?



None.
Whats the problem with the original Power transformer?
Why do you think there's anything to upgrade in the power transformer?

Thanks for the reply - the reason why I want to replace the caps and resistors is that the mic doesn't sound convincingly good to my ears. I bought it used and it is likely 15 years old or so.

I am not a recording engineer or and engineer of any sorts, I am an opera singer, but would like to try and solve this myself. Reading the schematic is only partly possible for me - not least because of the illegible smeared and pixelated text.

The minute I hooked up the mic it had a very audible hum, inside the PSU one of the electrolytic caps had visibly burst. After replacing it the hum gone, but I still think the mic sounds weak. Knowing one cap was bad, I feel it is best to replace all, so I am sure I am getting the optimal sound from the mic. Same with the transformer, just thought I might as well change it, since I am renewing everything else.

In regards to the cable connector, I guess the middle connector isn't used, since you recommended 7-conductor cables. Or is the 8th the shield? When you open the aviator connector, do both ends have clear indication of wire numbering, so I know where to solder what?

Last question, knowing I am no expert and have no experience reading a schematic diagram, could you answer the following:
The two resistors soldered together to replace the 300k single resistor have very big solder joints that completely overlaps one of the joints/pin holes of the resistor next to/behind it, is this okay/done on purpose?


Thanks a lot again for your answers!

 

[pucho812]

usually when recapping we do the electrolytics. Other capacitors are usually ok unless they are failed as well. No need to replace what is not broken or failing. Changing caps depending position will change sonics, proceed with caution.

Ecc83 is euro numbering for a 12ax7 tube. A is a variant.
Initially, the “A" suffix had a controlled heater warm-up for use in a series filament circuit.
Series filament was a cost-saving technique used in cheap tube radios. It does not apply to modern tube gear.
And often times the suffix doesn’t mean anything in modern tubes.
For example, Sovtek has 12AX7WA, 12AX7WB, and 12AX7WC. These are near-identical tubes with slightly different characteristics.

What transformer do you need to replace and why? Power transformer, has it failed?
Audio transformer, what are ratios? What is the sonic and what do you not like about it?

Cable, will be just a pass through.
Do you have your original cable? If so did it fail? You might be able to repair it depending what happened. If you can’t repair it, can desolder the ends and reuse them unless that’s the part that is broken.

 

[Adam Frandsen]

usually when recapping we do the electrolytics. Other capacitors are usually ok unless they are failed as well. No need to replace what is not broken or failing. Changing caps depending position will change sonics, proceed with caution.

Ecc83 is euro numbering for a 12ax7 tube. A is a variant.
Initially, the “A" suffix had a controlled heater warm-up for use in a series filament circuit.
Series filament was a cost-saving technique used in cheap tube radios. It does not apply to modern tube gear.
And often times the suffix doesn’t mean anything in modern tubes.
For example, Sovtek has 12AX7WA, 12AX7WB, and 12AX7WC. These are near-identical tubes with slightly different characteristics.

What transformer do you need to replace and why? Power transformer, has it failed?
Audio transformer, what are ratios? What is the sonic and what do you not like about it?

Cable, will be just a pass through.
Do you have your original cable? If so did it fail? You might be able to repair it depending what happened. If you can’t repair it, can desolder the ends and reuse them unless that’s the part that is broken.

Thanks so much for this answer first of all! The schematic is so hard to read, because of how pixelated it is, but between looking inside my mic, a picture of someone else’s mic online and the schematic I managed to write down all resistor sizes and cap types. I am not an expert on what position they are in or what they do.

From the picture of another similar mic, I could see that several of my caps and resistors had been changed, all the electrolytic caps, and all the small 104’s have been changed to 104j’s, which I guess is an upgrade. I am an audiophile, so I probably buy into too much snake oil haha, so I was gonna replace all the caps with silver mica where I could and good brands like wima, nichicon, TAD, kemet etc.. The ones in it now are all chinese with strange names.

Also as I said one 300k resistor was replaced with two metal film resistors soldered together, and the joint has so much solder it looks like it overlaps the joint of the adjacent resistor, which may or may not be on purpose. The transformer is the power transformer, was gonna see if I could find something better quality than the old one - this may just be me believing in unicorns, I don’t know.

In terms of the ecc83a, I got confused because someone on a forum post, which I cannot find now of course, wrote it was a low gain low noise version of the normal ecc83 with a gain of only 70… I have tried several tubes in the mic, 12ay7, 12at7, ecc83, 5751, and ecc803s. The ecc803s sounds horrible, the 12at7 sounds fine, the 12ay7 sounds probably best, the ecc83 is a nos mullard and sounds good too, and the 5751 is a gold pin tungsol, which also sounded fine. The weird thing is they all require more or less the same gain adjustments on my interface to reach the same level, why is that?

In terms of the cable I am confused about how to solder it in the right order. On the sommer cable octave, I see that there are different sizes to each conductor, which must mean they need to go specific places. I can understand that 3 are for the xlr, 3 are for the power and ground and one is for the mic polarity dial. I don’t understand why they used an 8 pin aviation connector if only using 7 condcutors, inside the psu the middle pin of the connector is not soldered to anything in the pcb, it is just left blank.

Thanks again,
Adam

 

[pucho812]

Thanks so much for this answer first of all! The schematic is so hard to read, because of how pixelated it is, but between looking inside my mic, a picture of someone else’s mic online and the schematic I managed to write down all resistor sizes and cap types. I am not an expert on what position they are in or what they do.

From the picture of another similar mic, I could see that several of my caps and resistors had been changed, all the electrolytic caps, and all the small 104’s have been changed to 104j’s, which I guess is an upgrade. I am an audiophile, so I probably buy into too much snake oil haha, so I was gonna replace all the caps with silver mica where I could and good brands like wima, nichicon, TAD, kemet etc.. The ones in it now are all chinese with strange names.

Also as I said one 300k resistor was replaced with two metal film resistors soldered together, and the joint has so much solder it looks like it overlaps the joint of the adjacent resistor, which may or may not be on purpose. The transformer is the power transformer, was gonna see if I could find something better quality than the old one - this may just be me believing in unicorns, I don’t know.

In terms of the ecc83a, I got confused because someone on a forum post, which I cannot find now of course, wrote it was a low gain low noise version of the normal ecc83 with a gain of only 70… I have tried several tubes in the mic, 12ay7, 12at7, ecc83, 5751, and ecc803s. The ecc803s sounds horrible, the 12at7 sounds fine, the 12ay7 sounds probably best, the ecc83 is a nos mullard and sounds good too, and the 5751 is a gold pin tungsol, which also sounded fine. The weird thing is they all require more or less the same gain adjustments on my interface to reach the same level, why is that?

In terms of the cable I am confused about how to solder it in the right order. On the sommer cable octave, I see that there are different sizes to each conductor, which must mean they need to go specific places. I can understand that 3 are for the xlr, 3 are for the power and ground and one is for the mic polarity dial. I don’t understand why they used an 8 pin aviation connector if only using 7 condcutors, inside the psu the middle pin of the connector is not soldered to anything in the pcb, it is just left blank.

Thanks again,
Adam

104 and 104j is the same capacitance value the J denotes percentage tolerance.
Resistors in series add. Resistors in parallel divide. Many times a company subs a value to meet a deadline. Parts are harder to get now days.
To tell if it overlaps, test for continuity. There maybe parallel connections going on.

There is no version of ecc83/12ax7 that has a lower gain factor that I am aware of. At that point it’s a different tube and since it has same pin out as others could easily be mistaken. I have had in the past mislabeled tubes. We had a batch of tubes from Asia labeled as one type but they tested as another type. As they were of the 12A@7 the heaters were the same as was pinout but they were not 12at7 even though they were labeled as such. You will be fine with subs there until your not.

Unless the power transformer is not working in some fashion, then there is no reason to replace it.

As for the cable, you have a schematic, it should have PIN numbers and should be legible enough to work out. If you post what you have, we can help you further here but again if the cable is ok, why replace it?

 

[Adam Frandsen]

104 and 104j is the same capacitance value the J denotes percentage tolerance.
Resistors in series add. Resistors in parallel divide. Many times a company subs a value to meet a deadline. Parts are harder to get now days.
To tell if it overlaps, test for continuity. There maybe parallel connections going on.

There is no version of ecc83/12ax7 that has a lower gain factor that I am aware of. At that point it’s a different tube and since it has same pin out as others could easily be mistaken. I have had in the past mislabeled tubes. We had a batch of tubes from Asia labeled as one type but they tested as another type. As they were of the 12A@7 the heaters were the same as was pinout but they were not 12at7 even though they were labeled as such. You will be fine with subs there until your not.

Unless the power tube is not working in some fashion, then there is no reason to replace it.

As for the cable, you have a schematic, it should have PIN numbers and should be legible enough to work out. If you post what you have, we can help you further here but again if the cable is ok, why replace it?

Thanks for such a swift reply, the only schematics I have was what I found here on this forum: SE Electronics and SE Z5600a II schematic
It is the z5600(a) II not the older z5600 or z5600a.

 

[pucho812]

Thanks for such a swift reply, the only schematics I have was what I found here on this forum: SE Electronics and SE Z5600a II schematic
It is the z5600(a) II not the older z5600 or z5600a.

You mention in your first post

“Hi - I need to make a new cable for the z5600a II”

 

[Adam Frandsen]

You mention in your first post

“Hi - I need to make a new cable for the z5600a II”

Yes

 

[Whoops]

This is the best help I can provide to you after reading all the posts.

You don't even know or have any idea of what a power transformer does, you also don't have the basic electronic knowledge or skills to modify a microphone, so you don't have what it's needed to do the work that you purpose to do.
You also have no idea if the microphone actually sounds as it should or not, so you want to modify something that probably is already up to his best in terms of performance.

Also you said that you're an Opera singer, and not an engineer of any sort, so you should stay that way, you should just Sing, we should do what we are best.
There's high voltages inside the PSU and the microphone, it can be dangerous, and it's better that you are an Opera Singer now than becoming a Singer in the after life.

You will not improve the sound of that mic and you probably might up end up making it actually worse.

So, saying this, you don't like the sound of the mic, that's fine.
Sell that microphone to someone that likes it and with that money buy a microphone that you like, there's plenty of good options, microphones are a matter of personal taste.

I hope you humbly understand this and don't think it's anything personal, I'm just being honest and helpful

Best regards

 

[Adam Frandsen]

This is the best help I can provide to you after reading all the posts.

You don't even know or have any idea of what a power transformer does, you also don't have the basic electronic knowledge or skills to modify a microphone, so you don't have what it's needed to do the work that you purpose to do.
You also have no idea if the microphone actually sounds as it should or not, so you want to modify something that probably is already up to his best in terms of performance.

Also you said that you're an Opera singer, and not an engineer of any sort, so you should stay that way, you should just Sing, we should do what we are best.
There's high voltages inside the PSU and the microphone, it can be dangerous, and it's better that you are an Opera Singer now than becoming a Singer in the after life.

You will not improve the sound of that mic and you probably might up end up making it actually worse.

So, saying this, you don't like the sound of the mic, that's fine.
Sell that microphone to someone that likes it and with that money buy a microphone that you like, there's plenty of good options, microphones are a matter of personal taste.

I hope you humbly understand this and don't think it's anything personal, I'm just being honest and helpful

Best regards

Hard to take something personal from a person who doesn't know me or what I know.

I want to fix my mic myself and exchange/upgrade any parts I see fit, since it is my microphone. One capacitor has already failed, because the mic is old and I am not gonna wait around for another one to fail, and go have it fixed each time. I also want to be sure I get the most out of the mic, and that any parts haven't dropped below spec. If you don't wish to help and have such low social IQ and public behaviour, as you have just displayed, just refrain from commenting and go about your day, the other person has been helpful and polite, which is much appreciated.

I already wrote I am no expert, and it is still my right to fix my own mic even though I am not an engineer, cook my own food even if I am no chef, build my own furniture even if I am not a carpenter - I want to explore this as a hobby, not to go commercial.

I am not working with any super or ultra capacitors and always let everything discharge for an hour before opening it up. The electrolytic caps in the mic are 25v, if I get new parts for the PSU, I will consider taking it to my local audio dealer here, let's see... BTW. the name of the forum is groupDIY, not professional engineering and electronics forum - DIY stands for "Do it yourself". Enjoy your day. I still hope the other user will continue his help - thanks in advance!

 

[johnR]

Replacing the cable won't hurt. I've seen original Z5600a II cables with a manufacturing fault that caused stray copper strands to poke through the insulation of individual cores, in so many places that short circuits were a regular occurrence.

Electrolytic capacitors can be replaced with any good quality caps of the right value that match or exceed the voltage spec and can fit in the available space. Power supply filtering can often be improved by using higher value caps if there's enough space. Stick to the original values for the cathode bypass cap and output dc blocking cap in the mic unless you know what you're doing.

I wouldn't bother replacing transformers unless you have reason to believe they've developed faults. Have you checked the PSU voltages with a multimeter?

Regarding the sound of the mic, the Z5600a II is designed deliberately to give a heavily coloured sound, with high harmonic distortion and a lot of sibilance. Is this what you want?

 

[pucho812]

Yes

Ok the mic mentioned in the first post, is the schematics you linked to, so I don’t quite understand what more you need.

I also can’t tell if anything is actually broken. As suggested if it’s not broken, don’t fix it.
What is actually broken on this mic? I don’t care if you like the sonic, but what is not working here exactly?

 

[Adam Frandsen]

This is the best help I can provide to you after reading all the posts.

You don't even know or have any idea of what a power transformer does, you also don't have the basic electronic knowledge or skills to modify a microphone, so you don't have what it's needed to do the work that you purpose to do.
You also have no idea if the microphone actually sounds as it should or not, so you want to modify something that probably is already up to his best in terms of performance.

Also you said that you're an Opera singer, and not an engineer of any sort, so you should stay that way, you should just Sing, we should do what we are best.
There's high voltages inside the PSU and the microphone, it can be dangerous, and it's better that you are an Opera Singer now than becoming a Singer in the after life.

You will not improve the sound of that mic and you probably might up end up making it actually worse.

So, saying this, you don't like the sound of the mic, that's fine.
Sell that microphone to someone that likes it and with that money buy a microphone that you like, there's plenty of good options, microphones are a matter of personal taste.

I hope you humbly understand this and don't think it's anything personal, I'm just being honest and helpful

Best regards

Hard to take something personal from a person who doesn't know me or what I know.

I want to fix my mic myself and exchange/upgrade any parts I see fit, since it is my microphone. One capacitor has already failed, because the mic is old and I am not gonna wait around for another one to fail, and go have it fixed each time. I also want to be sure I get the most out of the mic, and that any parts haven't dropped below spec. If you don't wish to help and have such low social IQ and public behaviour, as you have just displayed, just refrain from commenting and go about your day, the other person has been helpful and polite, which is much appreciated.

I already wrote I am no expert, and it is still my right to fix my own mic even though I am not an engineer, cook my own food even if I am no chef, build my own furniture even if I am not a carpenter - I want to explore this as a hobby, not to go commercial.

I am not working with any super or ultra capacitors and always let everything discharge for an hour before opening it up. The electrolytic caps in the mic are 25v, if I get new parts for the PSU, I will consider taking it to my local audio dealer here, let's see... BTW. the name of the forum is groupDIY, not professional electronics forum - DIY stands for "Do it yourself". Enjoy your day. I still hope the other user will continue his help - thanks in advance

Ok the mic mentioned in the first post, is the schematics you linked to, so I don’t quite understand what more you need.

I also can’t tell if anything is actually broken. As suggested if it’s not broken, don’t fix it.
What is actually broken on this mic? I don’t care if you like the sonic, but what is not working here exactly?

I know those are the schematics for the mic, which is why I linked to them - the whole point is 1. the quality is awful and impossible to read, 2. Maybe if one knows what exactly they are looking for and at, they can decifer it or at least point me where to look - that was the whole point. I want to make a new cable, and I shouldn't have to go into lengthy explanations as to why - I have extras of all my cables, what if I am out recording and someone yanks the cable and it breaks, it is already flimsy quality, then I don't have a spare? The mic sounds weak and responds poorly, it requires a lot of gain too.

 

[Adam Frandsen]

Replacing the cable won't hurt. I've seen original Z5600a II cables with a manufacturing fault that caused stray copper strands to poke through the insulation of individual cores, in so many places that short circuits were a regular occurrence.

Electrolytic capacitors can be replaced with any good quality caps of the right value that match or exceed the voltage spec and can fit in the available space. Power supply filtering can often be improved by using higher value caps if there's enough space. Stick to the original values for the cathode bypass cap and output dc blocking cap in the mic unless you know what you're doing.

I wouldn't bother replacing transformers unless you have reason to believe they've developed faults. Have you checked the PSU voltages with a multimeter?

Regarding the sound of the mic, the Z5600a II is designed deliberately to give a heavily coloured sound, with high harmonic distortion and a lot of sibilance. Is this what you want?

Thanks for the answer! Yes, I really want a spare cable and especially considering the poor quality you describe. I have all the resistors and caps to replace the old ones now - that was fairly easy to figure out. What I was asking about was the reverse male plug of the GX20, which I cannot find anywhere... Also wanted to know how to solder the wires of the cable in the correct order - I understand that information is somewhere in the schematics, I just cannot find it/don't know where to look and also the schematics are almost impossible to read. I will try and measure the voltages as you said, I am still in the research fase of the project. I don't mind some harmonic distortion if it adds character, but sibilance I am not a big fan of - neither of the two was why I bought the mic, and I cannot say that it is displaying those characteristics as something is quite off... I have a peluso pk-47, that I will try and install as well...

 

[Whoops]

reverse male plug of the GX20

It's called female, and it's pretty easy to find

 

[Adam Frandsen]

It's called female, and it's pretty easy to find

No, I don't mean the female plug you purchased on the mic end of the cable, I mean the reverse male connecter that screws on to the power supply. I can find it for GX16, name is straight reverse male GX16 8 pin, but cannot find the GX20. I found one manufacturer who has one with a cutout in the ring instead of the little square alignment bump inside the sE plug.

 

[Adam Frandsen]

I did look inside the PSU and wrote down the color order of the wire soldered to the gx20 socket, cannot remember it off the top of my head but I think it was blue, white and black to the xlr, brown to the dial, and the remaining three to power. Not sure if this is right though and if i just reverse it for the cable - still need to know what size conductor goes where.. and if the middle is indeed not used, since nothing is attached inside the psu, could also have been done during a repair since it is a used mic… maybe the sleeve needs to be soldered there?

 

[Adam Frandsen]

Also contacted the sE distributor here in Taiwan asking for a replacement cable, and they wanted me to send in my current cable, because there apparently are 9 different versions of the cable according to them for this mic, and they cannot tell from my pictures which one I have, very strange and too much of a hassle and also me being without the cable and mic for I don‘t know how long. So I am doing it myself now. As of these last few minutes browsing the peluso website for a k87 capsule I found that they actually sell the connector: 8-pin Connector, Male Cable End - Peluso Microphone Lab

Not sure if they ship to Taiwan though, also it doesn’t specify if it is gx20 or gx16… but it looks right, price is also steep

 

[johnR]

It will be a lot cheaper to buy the connectors from an electronics supplier, not a mic manufacturer. A web search here in UK on duckduckgo for "GX20 connector" brings up a lot of results on ebay and amazon.

Here's a GX series catalog download page from a Chinese manufacturer:
https://www.renhotecpro.com/download/gx-aviation-connector-pdf-catalog-download/
Don't know if they'll sell small quantities but the catalog contains useful info and drawings so you can work out which connectors you need to look for.