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SE 2200a modification of the internal input circuitry
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Jean30
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#1
5th May 2012
Old 5th May 2012
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SE 2200a modification of the internal input circuitry

I just modified the input internal preamplifier and I feel sound is better, noise level is 3dB lower, less distorsion, very smooth sound, more bass and transcient frequencies. I used a pair of microphones to do the tests, modifying only one.

just hear :
Voice before mod : SE 2200a 01 Voix micro non modifié.wav
Voice after mod : SE 2200a 02 Voix micro modifié.wav

Guitar before mod : SE 2200a 03 Guitare micro non modifié.wav
Guitar after mod : SE 2200a 04 Guitare micro modifié.wav

If you are interested, to do the mod yourself, you just need a soldering iron and just small wire for the basic but essential modification. I just had the impression to transform this cheap microphone in a very professional one. I don't have a Neumann U87 to compare, but it remains me this type of sound.

Just answer, and I will continue the thread with complete schematics, before/after, pictures and explainations.

The principe is just to rewire the capsule without the bad original capacitor.
Attenuation fonction is removed, but can be obtain again with a second step in the modifications.

Technically, original attenuation circuitry create unwanted capacitance and 3dB lost in signal, it decrease also high frequencies.
Input capacitor (to remove) is a 1nF ceramic type !!!!, lost of bass frequencies and granular sound.
#2
5th May 2012
Old 5th May 2012
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evostars is offline
Yeah, show me the pics! Im interrested in what you did.:D

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#3
5th May 2012
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evostars is offline
I thought the capsule itself was the main problem with this mic, but I'm not sure.

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Jean30
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5th May 2012
Old 5th May 2012
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OK Just we go !!!!!

Schématics :
BEFORE MOD ImageShack® - Online Photo and Video Hosting
BASIC MOD ImageShack® - Online Photo and Video Hosting
COMPLETE MOD ImageShack® - Online Photo and Video Hosting
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Pictures :
BEFORE MOD :
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
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MINIMUM MOD CAPSULE REWIRE(very easy):
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting
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REWIRE ATTENUATION FONCTION 0dB/-10dB (harder):
remove some part of tracks on the circuitry
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting

rewiring Drain R5 C4 because of the S1 remove
ImageShack® - Online Photo and Video Hosting

just before rewiring S1 you just need to delete another part of the circuitry
ImageShack® - Online Photo and Video Hosting

Sold the 100K resistor
ImageShack® - Online Photo and Video Hosting

wiring the S1, one point of soldering is directly on the inverter
ImageShack® - Online Photo and Video Hosting
---------------------------------------------------------------------------------
LESS CRITICAL MODIFICATIONS (easy)
Add a 47µF 63V capacitor
ImageShack® - Online Photo and Video Hosting
ImageShack® - Online Photo and Video Hosting

Replace C8
ImageShack® - Online Photo and Video Hosting

To add in parallel of C9
ImageShack® - Online Photo and Video Hosting

To add in parallel of C4
ImageShack® - Online Photo and Video Hosting

To add in parallel of C3
ImageShack® - Online Photo and Video Hosting
---------------------------------------------------------------------------------
Fournitures :
- Just thin wire for the minimum mod
- 1 100K metal resistor (no high précision needed) to have the 0dB/-10dB attenuation function again
- For the minor modifications
2 cap plastic film 0,47µF 63V or 1µF 63V (the 2nd one is for new followings modifications)
3 caps plastic film 220nF 63V
1 chemical cap 47µF 63V
2 caps plastic film 6,8nF or 2X8,2nF 63V
or 10nF + 4,7nF (63V)


A few dollars !!!!!

-------------------------------------------------------------------------------------------

NEW MODIFICATIONS :

-Remove C4 and replace it with metallic film capacitor 470nF 63V (or 1µF)
-Remove C6 with 10nF metal film cap (63V)
-Remove C5 with 4.7nF metal film cap (63V)

You can use also 6,8 nf (or 8.2nF) for C5 and C6
The more value, the less frequency bass cut knee

Optional :
Put a 470nf or 1µF 63V metal film capacitor in parallel of C7 (10µF 35V)
No audible effect, just secure in case of C7 malfunction

Original C4 was too high and chemical type, too much unwanted bass frequencies
Original C6 and C5 make distorsion and are not precise, so real knee is not 100 Hz but 85Hz, it's a good value and I kept it with new value.
When I used my 2 microphones in couple, there was a problem in bass cut position (problem of phase due to the low precision of C5 C6), now it's perfect.

Just an interesting phenomen is that bass response increase in proximity effect and again more if you take a vertical angle of 45° over the axis, now with 470nF C4, it's a little boomy in this position but before, it was critical and nearly impossible to use. Now, you can play with this effect on voices.

------------------------------------------------------------------------------------------

Explainations :

IMPORTANT CLARIFICATION, obviously, you lose the guarantee
Make sure your microphone is the same model because there are several series
No need to remove the bell at the bottom, there's just the transformer inside
take the opportunity to clean the many solder splashes
Be careful, protect the capsule during labor, no electrostatic clothes, soldering iron has to be well insulated and grounded

After modfication, output phase is inverted, so if you need, you can exchange the yellow an green output wires to have again the original phase (no difference for the sound but for relative other microphones used simultanously)

The circuit design has two major flaws. Before modification, the capsule is wired like interchangeable capsules microphones as, while it is possible to dispense with the 1nF capacitor insulation at the entrance of the circuit, plus it is a ceramic model so that plastic wrap or polystyrene is most suitable result, its grainy and possibly current leakage, loss of bass.

The solution, rewire the capsule by connecting the black wire to the positive power supply (instead of the mass) and the red wire membrane directly to the input of the FET. The input impedance is increased since there is only one resistor or 1G instead of two (parallel). R2 and C1 C2 disappear and you can remove the teflon pad, it is best to shear C1 and C2. The black wire of the capsule is to rewire a bit further, it may be a bit too short

The second big problem is due to the attenuator 0/-10dB already used the principle is rather questionable (with a capacitance of 12pF in counter reaction), although used in micro prestigious, but more importantly, the path of the circuit, insulation and the very presence of all metal stake, creating a signal attenuation and possible loss of transient. On such critical points, we can mechanically transmit the action of a micro swich nearby components, which is not the case here.

To change the minimum that I strongly advise you (I have not heard of significant improvement for the other changes), there is provision for 0 euros and 1/2H work. If you stop here, you lose the function 0/-10dB but more importantly, the sound becomes more neutral, sharp and without distortion, YOU WIN 3 to 4 dB GAIN, so much less breath. The bandwidth is extended. Leaving the cable attenuation, the gain does not improve (or breath), but the sound is still better (not much). In all cases, the very useful function of cutting bass frequencies with the other swich is kept.

The maximum technical level is reduced by 10+3 = 13dB. For powerful sound sources, it will go to the next step which is the most difficult (but I'm sure you can do it !!!).

The attenuator function is recreated by playing on the gain of the input stage via the capacitor C3 47uF, fluke, by disconnecting it, we lose around 10dB of gain, but there it is to maintain a closed circuit for the regular 0dB gain, you have to get the connection point directly to the terminals of the switch. Moreover, the lamentable topology of the circuit requires some developments. Following the diagram and photos, you can get there.

Other changes may reduce the noise of the chemical capacitors in series in the sound path. At these levels, it does not generally pose no problem, but considering the price components, putting plastic film caps in parallel can prevent future degradation of chemical caps.

The 47uF capacitor chemical added near the resistors R12 R13 filter is especially good for the positive capsule powering, replace the 1uF capacitor chemical model by a plastic film to decrease noise, I had not the 1µF value in my set, so 0.47 uF it good, but if you buy components, take 1uF 63V (and verify it's not a too big component).

I still do not understand what the purpose of the diode, perhaps to compensate for drift of the FET? but anyway, it's filtered back.

Initially, you may also find that the records after modif are flat, they are mostly less flattering, less distortion and for my taste, very professional.

I have not had in hand a long Neumann, but from the first test of the 2200 SE, I was a little disappointed, but now, I feel closer to the Neumann or the C414.
#5
5th May 2012
Old 5th May 2012
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evostars is offline
Cool! Thx. Gona check it out :-)
#6
5th May 2012
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evostars is offline
Argggg... SMD
:-(
i don't like those small parts at all
Jean30
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5th May 2012
Old 5th May 2012
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No problem with SMD, all mods are with big components, no processor or small transistors. Basic mod need only 1/2 hour to work incuding time to find your soldering iron.
#8
5th May 2012
Old 5th May 2012
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manzini is online now
Cool! Thanks a lot Jean30 !!

Only a little question, this mod is for a se2200a, 'a' version, ok.

Do you know if se2200A 'A' it's the same ? same capsule and/or circuit ?
#9
5th May 2012
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Nice thread Jean... the question is though... did it fix the sibilance issues?
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5th May 2012
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Sorry.

I see on "15se2200aajoutducondode" pic the se2200A (uppercase 'A') pcb legend
Jean30
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5th May 2012
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Quote:
Originally Posted by manzini View Post
Cool! Thanks a lot Jean30 !!

Only a little question, this mod is for a se2200a, 'a' version, ok.

Do you know if se2200A 'A' it's the same ? same capsule and/or circuit ?
The exact reference of my microphone is sE2200a, a special offer before the new black model coming soon. I paid it 166 Euros, no fly case, head basket included.

I can't answer to the 2nd question, just compare with your microphone, you can easily open it unscrewing the bottom (no risk for the guarantee)
Jean30
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#12
5th May 2012
Old 5th May 2012
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Quote:
Originally Posted by manzini View Post
Sorry.

I see on "15se2200aajoutducondode" pic the se2200A (uppercase 'A') pcb legend
It's a standard pcb I suppose. This area is used for double capsule multi pattern microphones, there is also a 2nd hole on the epoxy disk (with swiches) wich is used for the 2 wires of the 2nd capsule if present.

There is a new version : the SE2200A II (multi pattern)

The old version sE 2200

the future version of the sE 2200a is black
#13
5th May 2012
Old 5th May 2012
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Quote:
Originally Posted by Jean30 View Post
.... you can easily open it unscrewing the bottom (no risk for the guarantee)
Oh Yes I will do in few weeks, I am away from my mic. It's a se2200A (uppercase) version, anniversary or some thing like this I remember with fligtcase, shockmount, etc. I will post here.
Jean30
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5th May 2012
Old 5th May 2012
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Quote:
Originally Posted by FlyingPanda View Post
Nice thread Jean... the question is though... did it fix the sibilance issues?
Listen the small tests, for me it was a problem of distorsion wich create sibilance. I feel the sound is softer after mod and if you feel the sound has too much high frequencies, soften it with a baxendall is possible.

Voice test (and guitar) were made without pop screen and 0dB gain, no bass cut.

Input on a RME fireface UC, original microphone had 3dB more input sensitivity (and 3dB more noise). I tried that to have the same level, obviously, the position are not exactly the same, but as closer as possible. You can hear that with the small difference between the color of the guitar.

Using it in ORTF couple, it seemed perfectly matched before mod.
After mod, the precision is increased and I heard the small differences better than before, reflections in the room, stereo image and also the minimal differences of the capsules.

I will do next some new tests but without old version microphones, the 2 are now modified and will never come back to their original flattering and distorded sound.

In fact, it was a good surprise, I just reached less noise and everything is better. I read the Michael JolY comments, and he talked about the problem of the switches. I remember my university knowledge (far away) about electricity and the load depends also of the quantity of material.

If your car is blasted during a storm, you can be killed when going out of the car, because you will discharge all the mass of your car.

It's the same thing with the switches, even without connexion, all the material inside will follow the voltage of the capsule, and the less you have, the best it is.
Jean30
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#15
5th May 2012
Old 5th May 2012
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Quote:
Originally Posted by manzini View Post
Oh Yes I will do in few weeks, I am away from my mic. It's a se2200A (uppercase) version, anniversary or some thing like this I remember with fligtcase, shockmount, etc. I will post here.
OK, compare the pcb, if not exactly the same, have a look on the diagrams, try to make a new one with your version and post it.

I'm certain that there is no big differences and the modifications will be very similar, but you will have to uncerstand each action you will do (that's better even if you have the same pcb)

Happy to see you have good interest about that, in fact I'm not very surprised with theese commercial choices, it's just a little annoying to pay 1000 dollars just for 10 dollars more components inside !!!!
#16
6th May 2012
Old 6th May 2012
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Quote:
Originally Posted by Jean30 View Post
Listen the small tests, for me it was a problem of distorsion wich create sibilance. I feel the sound is softer after mod and if you feel the sound has too much high frequencies, soften it with a baxendall is possible.

Voice test (and guitar) were made without pop screen and 0dB gain, no bass cut.

Input on a RME fireface UC, original microphone had 3dB more input sensitivity (and 3dB more noise). I tried that to have the same level, obviously, the position are not exactly the same, but as closer as possible. You can hear that with the small difference between the color of the guitar.

Using it in ORTF couple, it seemed perfectly matched before mod.
After mod, the precision is increased and I heard the small differences better than before, reflections in the room, stereo image and also the minimal differences of the capsules.

I will do next some new tests but without old version microphones, the 2 are now modified and will never come back to their original flattering and distorded sound.

In fact, it was a good surprise, I just reached less noise and everything is better. I read the Michael JolY comments, and he talked about the problem of the switches. I remember my university knowledge (far away) about electricity and the load depends also of the quantity of material.

If your car is blasted during a storm, you can be killed when going out of the car, because you will discharge all the mass of your car.

It's the same thing with the switches, even without connexion, all the material inside will follow the voltage of the capsule, and the less you have, the best it is.

Thanks... Yeah I didn't hear much difference in the high end of the mic and i am thinking a capsule change will effect the frequency response more... Self noise was never much of an issue to me...
Jean30
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#17
6th May 2012
Old 6th May 2012
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I will test it with a piano, I'm OK with you about the noise and I think that if you want to change the capsule, you better have also to change the entire pcb, to have transformerless output.

Don't forget that the geometry of the grid and the cone below the capsule are very important.

Before mod, it was impossible to have a clean sound, now, it's good. every microphone has a character, but, we often want the perfect microphone and forgot that good eq do great job.

You can remove the internal layer of the grid, but you cannot put it again if the sound becomes bad. Everything is important and if I had to change everything inside, I would buy a very very low cost microphone
Jean30
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#18
17th May 2012
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I just added it in older modifications, but I made new good improvements

NEW MODIFICATIONS :

-Remove C4 and replace it with metallic film capacitor 470nF 63V (or 1µF)
-Remove C6 with 10nF metal film cap (63V)
-Remove C5 with 4.7nF metal film cap (63V)

You can use also 6,8 nf (or 8.2nF) for C5 and C6
The more value, the less frequency bass cut knee

Optional :
Put a 470nf or 1µF 63V metal film capacitor in parallel of C7 (10µF 35V)
No audible effect, just secure in case of C7 malfunction

Original C4 was too high and chemical type, too much unwanted bass frequencies
Original C6 and C5 make distorsion and are not precise, so real knee is not 100 Hz but 85Hz, it's a good value and I kept it with new value.
When I used my 2 microphones in couple, there was a problem in bass cut position (problem of phase due to the low precision of C5 C6), now it's perfect.

Just an interesting phenomen is that bass response increase in proximity effect and more if you take a vertical angle of 45° over the axis, now with 470nF C4, it's a little boomy in this position but before, it was critical and very uneasy to use. Now, you can make paradoxal sets, with cutting bass ON and 45° takes to have different effects on voice.
#19
22nd May 2012
Old 22nd May 2012
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Did anyone else successfully try out this mod?
Jean30
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#20
23rd May 2012
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I posted also on a French forum and someone made the entire modifications except the new -10dB attenuation system. everything is OK for him and he noticed the same improvements, he suggest me to change the output transformer, but we didn't tried that now.

He used very big film capacitor (630V) and it's not usefull and takes a lot af place. As I wrote, the main change is when you put the capsule directly on the FET input, so bass frequencies are improved... a little bit too much and C4 (5µF) has to be replace with a 1µF or 470nF film capacitor. the other modifications are not so essential.

The main issue in this microphone is the ceramic capacitor input (distorsion) and the attenuator (in conter reaction) wich has loss of current (-3dB) even in OFF position. It creates relative high noise level, distorsion, bad transcient response and lost in bass frequencies.

I recently recorded my folk guitar and had the best result I ever had before with my Oktava MK12, I was also surprised with the distance (about 70cm) to have the good sound, with MK12, I was very close, and now I take more effect of the natural reflections without loosing presence.

In my first takes before modifications, guitar was a little granular and not clean, may be an effect, but impossible to remove.
Jean30
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#21
20th August 2012
Old 20th August 2012
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Small test of voice with speak T, S and Pop

Hello, a member asked me to test some s, p, t and voice, I'm not singer, so it's just a small speak with 4 distances records, 5, 10, 15 and 20 cms (2, 4, 6, 8 inches). The SE2200A is the modified version (I've not any more the original version).

Input record levels are approximativly adjusted to obtain the same level (the #4 is a little higher). No attenuation on the microphone, Low cut filter is ON, no anti pop screen was used. The vertical angle is very important (more bass if you speak on the top) but I tried to be in the axis. The room has reflexions and add color in high frequencies, you can heard that easily in record 3 and 4, but record 1 and 2 has very important proximity effect and a screen would be necessary for singers. With the low cut filter ON, the result is rather good without screen and with distance over 10 inches, you don't need screen.
For my use, I never found any problem with this microphone and it works very well in all situations with obviously the fact that it's a 1 inch microphone and you have to find the good place and the good sound source !!!


Pop Test SE2200A.wav
#22
21st April 2013
Old 21st April 2013
  #22
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nervousfede is offline
If someone is still interested...
In my 2200A, the circuit is completely Through Hole. No SMD at all.
Anyway the schematic is exactly the same (except for C8 which is not eletrolytic).
Even easier to mod. I have added parallel capacitors on the solder side of the PCB.
Jean30
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#23
21st April 2013
Old 21st April 2013
  #23
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Do you hear some improvements ?

I think small change could be a little more precision if you have changed C6 and C5, but removing C1 and rewiring the capsule for direct drive with the input transistor G1 is really the most important change to do. It may be too much if you want to keep the original character of this microphone.

As you saw, the new versions of SE 2200 are certainly improved, but price is twice !!!
#24
21st April 2013
Old 21st April 2013
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nervousfede is offline
Yes, I have also replced C5 and C6.
Of course I did all the capsule rewiring which is the most important change.
I have also replaced C7 with a higher quality one and added a 470nF film parallel.
Jean30
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#25
22nd April 2013
Old 22nd April 2013
  #25
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Super, good job. I'm sure you will have beautifull records !!!!
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