Noob needs help with z5600a II mic repair

[RoadrunnerOZ]

Yes, two different ones - one like you linked to but 1/2 (which is still bigger physically than what is there now) and one 1.2 watt that is actually a little
smaller, but with +-5% tolerance instead of 1%.. The 51Mohm ones were only available in one size, 18mm long, so will have to be creative with placement and float them off the board above the surrounding components, but it should be fine...

Better off using the 1% - I know with other mics I’ve worked on 1% is the norm. There’s no need to worry about wattage in the 1GΩ - it’s in the microwatts at the voltage used here.

 

[Khron]

Better off using the 1% - I know with other mics I’ve worked on 1% is the norm. There’s no need to worry about wattage in the 1GΩ - it’s in the microwatts at the voltage used here.

And tolerance is even less of an issue at those values - good luck measuring much of a difference (not to mention hearing any) between 900Meg and 1.1Gig...

 

[RoadrunnerOZ]

And tolerance is even less of an issue at those values - good luck measuring much of a difference (not to mention hearing any) between 900Meg and 1.1Gig...

And also try measuring the voltage - when I did my apprenticeship in the early ‘70s we had very high impedance VTVM voltmeters and that gear is not really available so readily, so you can’t measure the voltage present at the rear diaphragm or the backplate as the meter will act as a shunt - the only place you can measure the 0 - 120V is at the selector switch - any drift in value of the resistor chain around the switch or in the regulation voltage of the zeners will cause the centre position to shift. As far as the resistance values go, the point is that in the cardioid position of the selector switch the voltage on the rear diaphragm is supposed to match that of the backplate which relies on the switch providing the right voltage, the 51MΩ resistors being the same and the 1GΩ being fairly close - as you say you wouldn’t hear the difference, as it’s not affecting sound quality but the amount of rear signal present in cardioid - a few volts either way will shift between pointing toward Omni or Figure 8 - not a great issue with a microphone. The sonic quality of the mic is more dependent on the capacitors and resistors around the tube being up to scratch and at the right value to make the tube work as it should.

 

[Adam Frandsen]

And also try measuring the voltage - when I did my apprenticeship in the early ‘70s we had very high impedance VTVM voltmeters and that gear is not really available so readily, so you can’t measure the voltage present at the rear diaphragm or the backplate as the meter will act as a shunt - the only place you can measure the 0 - 120V is at the selector switch - any drift in value of the resistor chain around the switch or in the regulation voltage of the zeners will cause the centre position to shift. As far as the resistance values go, the point is that in the cardioid position of the selector switch the voltage on the rear diaphragm is supposed to match that of the backplate which relies on the switch providing the right voltage, the 51MΩ resistors being the same and the 1GΩ being fairly close - as you say you wouldn’t hear the difference, as it’s not affecting sound quality but the amount of rear signal present in cardioid - a few volts either way will shift between pointing toward Omni or Figure 8 - not a great issue with a microphone. The sonic quality of the mic is more dependent on the capacitors and resistors around the tube being up to scratch and at the right value to make the tube work as it should.

For the electrolytic caps I got UVZ2W010MPD1TD and UFG1E101MPM1TD - I have several others that I sourced locally, but I don‘t really know their specs, as they aren’t stated anywhere. One kind reads low ESR on the side (see picture), but who knows … also they are 10mm diameter, which means they will touch at the base a little... Tried getting som Tantalum caps, but they were expensive and sold out/on backorder.

 

[Khron]

If an electrolytic has "low ESR" or "VENT" written on it, run like the wind and don't look back...

 

[Adam Frandsen]

If an electrolytic has "low ESR" or "VENT" written on it, run like the wind and don't look back...

Hahaha, why is that?

 

[Khron]

None of the handful of reliable capacitor makers (Panasonic / Matsushita, United ChemiCon, Nichicon, Rubycon, Elna) has any of that printed on the sleeves of any of their products, while oooooh-so-many crap brands do.

Coincidence?

 

[Adam Frandsen]

None of the handful of reliable capacitor makers (Panasonic / Matsushita, United ChemiCon, Nichicon, Rubycon, Elna) has any of that printed on the sleeves of any of their products, while oooooh-so-many crap brands do.

Coincidence?

Haha - well, I think you are likely right, but Nichicon do put gold on their audiophile range, and I think this group of audiophile consumers, is who the chinese are targeting with this kind of labelling as well. My experience with tubes for example is that PSvane premium series tubes do sound really good, for sure they are over priced, but there are great chinese products too. These caps I found in a small electronics store in a basement in Taipei, they had all kinds of different brands thrown in together, but then they had this one box, where all were the same, which was this one. Cheap too, paid 6 Taiwanese dollar for one. They say 5000 hrs too… would be exciting if they are good. EDIT: Just found the brand, and it seems okay legit, it is a Taiwanese family company : Supertech - then again the caps on the website don’t have writing like that on the side, and 1uF low ESR doesn’t seem to be in the catalogue, likely fakes then. Will try and call them tomorrow and ask.

 

[Khron]

Me, i'd much rather trust my stash of scavenged ages-old brand-name electrolytics, than brand new no-names or known-crap brands (CapXon, Fuhjyyu, Aishi and the list goes on forever).

 

[RoadrunnerOZ]

When replacing anything in the way of capacitors in a tube circuit use known brands if you can. Also swapping an electrolytic for a tantalum is not necessarily a good idea if the circuit was designed with electrolytic characteristics in mind as overvoltage or any reverse voltage will kill a tantalum instantly which is why in PSU filters it’s a good idea to stick with what was used.
Low esr caps are made by the more reliable brands - Vishay, Nichicon and Rubycon all use different non solid electrolytes, water I believe is the basis for some ranges of the Rubycon e-caps electrolytes, to help achieve low esr, also using foil length to reduce series resistance. They don’t necessarily print that they are low esr on the side of the cap.
Look at the specs for guidance in the manufacturers catalog - not on the side of the cap - you can print whatever you like on plastic but that doesn’t make it true.
There was an instance of capacitor failure worldwide when a mis-copied formula was stolen from Rubycon, taken to China and used by the Luminous Town Electric Company resulting in catastrophic failure in computers causing massive recalls or thousands of very unhappy punters! These caps were made between 1999 and 2003, the recipe also went back to Taiwan where the same scientist team who nicked the formula started their own company making caps. The backlash lasted until well into 2007.
Beware of what you buy - stick to known brands. Buy from a reputable source - some knock-offs use copied text and brand logos.

 

[terry setter]

Just looked on microphone-parts.com and nothing there for SE, nothing under Z5600 either. Shame as it seems they cover a lot of mics too.

I strongly suggest you contact Microphone-parts.Com and ask what they have for your 5600. If nothing, you're only out a few minutes of your time. If they do, you're going to be way ahead. The 5600 is, I believe, a plate-follower gain stage followed by a cathode-follower impedance reducer. None of the great mics from history use this configuration. That doesn't mean it can't work, and even work well, but it is not easy to make that particular configuration sound as good as some of the other possibilities. I happen to be a plate-follower fan, but I recognize mics, such as the Sony C-37A, that use cathode-follower circuitry to great effect. BUT, the Neumann U47, M49, U67, Telefunken 251, RCA C12 (which are the gold standard of vintage tube microphones) are all plate-followers.

 

[Adam Frandsen]

Haha - well, I think you are likely right, but Nichicon do put gold on their audiophile range, and I think this group of audiophile consumers, is who the chinese are targeting with this kind of labelling as well. My experience with tubes for example is that PSvane premium series tubes do sound really good, for sure they are over priced, but there are great chinese products too. These caps I found in a small electronics store in a basement in Taipei, they had all kinds of different brands thrown in together, but then they had this one box, where all were the same, which was this one. Cheap too, paid 6 Taiwanese dollar for one. They say 5000 hr too… would be exciting if they are good.

Me, i'd much rather trust my stash of scavenged ages-old brand-name electrolytics, than brand new no-names or known-crap brands (CapXon, Fuhjyyu, Aishi and the list goes on forever).

Contacted Supertech today who were surprised to see a 1uF cap with their logo, as they had only made a special order in 2021 for a German customer - those looked different too. So in other words, they are fake.

 

[Nen'O]

I suggest you contact microphone-parts.com and buy one of their excellent upgrade kits that will fit right in. You'll end up with an improved mic, (though I love the Z5600's mechanical design).

One more vote for new pcb.
I don’t find this mic to sound anything special with stock parts. All of mine modified tube mics are waaay better than z5600 .

 

[Adam Frandsen]

One more vote for new pcb.
I don’t find this mic to sound anything special with stock parts. All of mine modified tube mics are waaay better than z5600 .

I will definitely try and make a mic from different parts at some point, but for now I will try and bring this back to its original intended state, and see how it sounds. I saw a comparison video of a u87 from mic and mod and an original, and the replica sounded horrible in comparison… Not saying that is always the case, but i want to make sure it is a good design, before i invest time and money…

 

[Adam Frandsen]

Ordered from DigiKey Monday and the package arrived today at my home here in Taiwan - impressive!

 

[Khron]

Mouser & FedEx move pretty quick too, usually less than a week from Texas to Europe.

 

[Adam Frandsen]

Mouser & FedEx move pretty quick too, usually less than a week from Texas to Europe.

I have a question whether or not to use Plastik 70, when I am done soldering…

 

[Khron]

Where, as in, on what part(s) of the circuit, and why?

 

[Adam Frandsen]

Where, as in, on what part(s) of the circuit, and why?

I saw a video where they just sprayed it all over the board, maybe this is not the right approach. It is supposed to protect against moisture etc., also to isolate the components

 

[RoadrunnerOZ]

I saw a video where they just sprayed it all over the board, maybe this is not the right approach. It is supposed to protect against moisture etc., also to isolate the components

Be warned - be careful. If you spray ANYWHERE near the capsule you will get micro-droplets of acrylic coating the diaphragm(s) - this will make the diaphragm heavier and completely change the frequency response and if uneven will unbalance the surface, affecting wave propagation that occurs on the diaphragm. Unless you mask the diaphragm with a soft cloth and then clingwrap or remove the circuit board to spray it you will ruin the capsule.