AKG Perception 420 Mod

[micolas]

Audio Freq
Out of curiosity, does the tsc-2 Capsule have the same character, behavior, as the one in the other microphone without problems?

 

[AUDIO FREQ]

Audio Freq
Out of curiosity, does the tsc-2 Capsule have the same character, behavior, as the one in the other microphone without problems?

It's a tad noisier...but I think that's because I am using a 2N3819 instead of a K30A. Maybe I should put in the K170 instead...doesnt it have better noise specs than the 2N3819?

 

[micolas]

It's a tad noisier...but I think that's because I am using a 2N3819 instead of a K30A. Maybe I should put in the K170 instead...doesnt it have better noise specs than the 2N3819?

I wonder if anyone here has had any experience with these:

https://a.aliexpress.com/_EQ0bK2t
I used Chinese 2SK30A from the Fame Studio C010 microphone and they behaved like those from Toshiba. I'm thinking of trying the ones on AliEx...

 

[micolas]

I wonder if anyone here has had any experience with these:

https://a.aliexpress.com/_EQ0bK2t
I used Chinese 2SK30A from the Fame Studio C010 microphone and they behaved like those from Toshiba. I'm thinking of trying the ones on AliEx...

As I said, I tested many brands of 2SK30A in the Fame Studio C010 microphone, which shares the same topology with many other microphones: jFET+Bipolar Transistor+Transformer (low ratio). The Chinese jFETs (taken from other cheap mics) performed very well according to the catalog specs. (including low noise).
I don't want to go off topic, but this microphone is very cheap, especially used, the capsule sounds decent, it has a good transformer, magnetically shielded, good jFET 2SK30A, sounds good even stock. It has a rather small capsule polarization of about 36V. By adding a dc/dc converter to put 58...63V on the capsule and adjusting the de-emphasis network to taste, it becomes a nice microphone for home-studio. Or he may be an excellent donor for a clone. The headbasket size is generous.
I bought it (used) for 20 euros.

 

[AUDIO FREQ]

As I said, I tested many brands of 2SK30A in the Fame Studio C010 microphone, which shares the same topology with many other microphones: jFET+Bipolar Transistor+Transformer (low ratio). The Chinese jFETs (taken from other cheap mics) performed very well according to the catalog specs. (including low noise).
I don't want to go off topic, but this microphone is very cheap, especially used, the capsule sounds decent, it has a good transformer, magnetically shielded, good jFET 2SK30A, sounds good even stock. It has a rather small capsule polarization of about 36V. By adding a dc/dc converter to put 58...63V on the capsule and adjusting the de-emphasis network to taste, it becomes a nice microphone for home-studio. Or he may be an excellent donor for a clone. The headbasket size is generous.
I bought it (used) for 20 euros.

20 Euros!!!!! What a deal! Ill see if there are any used locally. So during my testing, I swapped boards with a known good 420 with my bad 420, and the transformer board on the bad one is the culprit of the all the noise and low signal. So now, I gotta figure out what component on the transformer board is is bad...transformer measures the same on both, 129:59 give or take....

By the way, I am thinking about ordering these

https://www.aliexpress.us/item/3256...AT8cJ7zt&utparam-url=scene:search|query_from:
It says "original"...should I trust them????? Yikes IDK, but its pretty cheap.

 

[micolas]

By the way, I am thinking about ordering these

https://www.aliexpress.us/item/3256...AT8cJ7zt&utparam-url=scene:search|query_from:
It says "original"...should I trust them????? Yikes IDK, but its pretty cheap.

And I will order from another source:

https://a.aliexpress.com/_ExxnkJTWe will see which ones work properly, they are very cheap anyway.

 

[Khron]

It says "original"...should I trust them????? Yikes IDK, but its pretty cheap.

Why would they be original? The 2SK30A's been discontinued for "a few" years now, and even the reputable distributors (Mouser, Digikey etc) have no more in stock, so... "you do the math"

 

[micolas]

Why would they be original? The 2SK30A has been discontinued for a 'few' years now and even reputable distributors (Mouser, Digikey etc) no longer stock them, so... "you do the math"

Khron is right. They are not original Toshiba, we rarely find NOS, but the Chinese have made great technological advances, in fact they are able to produce almost anything with very good specifications. The only problem is rogue traders.

Many friends have encountered fake, falsely marked components.

So in DIY we also use selected Chinese parts

In fact, the AKG Perception series are built in China. With Chinese parts.

 

[cyrano]

The Chinese no longer accept waste from the west. Hence the number of fake components will have been reduced, since there no longer are children desoldering components over a small wood fire to sell them.

That leaves the crooks who relabel obsolete components, starting with whatever the cheapest new components possible are.

 

[micolas]

Khron is right. They are not original Toshiba, we rarely find NOS, but the Chinese have made great technological advances, in fact they are able to produce almost anything with very good specifications. The only problem is rogue traders.

Many friends have encountered fake, falsely marked components.

So in DIY we also use selected Chinese parts

Like I said, I'll give it a try. I ordered 2SK30A from aliex..
(Delivery will take 3 weeks but I hope it's worth the wait)
I will do tests and comparisons in different topologies, I will post the results.

 

[AUDIO FREQ]

I notice two 470pf capacitors soldered in parallel right on top of each other. Why is this like this? Are these the coupling caps?

 

[Khron]

I notice two 470pf capacitors soldered in parallel right on top of each other. Why is this like this? Are these the coupling caps?

Can you see what their legs are connected to? If it is as it seems, they might add up to be the C2 from the U87Ai schematic, between the +60v and -60v, so more like power filtering, rather.

 

[micolas]

I notice two 470pf capacitors soldered in parallel right on top of each other. Why is this like this? Are these the coupling caps?

Are you sure they are connected in parallel, i.e. forming a 940pF capacitor?

 

[micolas]

Hello friends, does anyone know if Perception 420(blue) and P420(black) have the same schematic? I have the newer version P420, I would try to draw the schematic by reverse engineering, of course some component values cannot be measured in assembly, but we can deduce them, or even improve the circuit.
Maybe it helps someone.
The electronics part built in a U87 style body would give better results.

 

[Khron]

Hello friends, does anyone know if Perception 420(blue) and P420(black) have the same schematic?

Not sure if it's in this thread or in another one, that i saw a FET/switch board with an SMD JFET, but could that be the main difference? Or has anyone seen the powder-blue Perception 420's with SMD JFETs?

 

[AUDIO FREQ]

Can you see what their legs are connected to? If it is as it seems, they might add up to be the C2 from the U87Ai schematic, between the +60v and -60v, so more like power filtering, rather.

They are both connected to pin 1 and 3 on the pattern switch. I took them out and put in a 1000pf polystyrene i had lying around. No difference. But it looks cleaner, and no more solder blobs all over the fet board. I actually desoldered everything and cleaned it up, so many blobs! So far, ALOT less noisier, and the output seems to be what I know of the AKG Perception to be like.

Waiting on the 2SK30A's I bought from Aliexpress. Will report to you guys how they work!

Also, going to do the kingkorg HF mod. Add a 560pf polystyrene to the bottom of the board where the 220pf ceramic smd capacitor is.

 

[AUDIO FREQ]

This looks like it could work also, maybe solder some legs on to it and make it through hole?

 

[micolas]

This looks like it could work also, maybe solder some legs on to it and make it through hole?

Or you can make a small PCB, pin adapter, so as not to overheat the jFET or break its very small, fragile terminals

 

[micolas]

Oh wait!
Audio FREQ,
there is an adapter for sot-23 for sale!

 

[Khron]

You'll probably wanna try to AVOID soldering the gate pin to that PCB adapter though...