CK12 Capsule Questions (for new DIY build & mod of WA251)

[Luckyadnan]

@Luckyadnan, @Khron, @pasarski

A little bit of talk-to-talk “just to put the record straight” about these mods that I suggested…

I never owned or brought any Warm Audio product, as I never owned or brought any Telefunken Elecroacoustik USA product, as I will never own or buy any product from any major Chin-o-Canadian-American-whatever the fukk “globalization” mass production companies, because as it is odiously they “fukk it up” by “Cutting Coners” any time that they try to copy on or to be said more clearly to steal on from the heritage and the tradition of historical European Microphone Companies like AKG, like Neumann, like Schoeps…

This will be as stupid to me as if I had bought any Japanese Sony, Nikon, Canon Digital cameras and wait from any of them afterwards, to take pictures as good as my photos that I take with my "Made in Germany" Leica SL3 digital camera, regardless of any lens I should use ...

But let’s go back to the AKG-Telefunken AG GmbH ELA-M 250 & to the ELA-M 251E microphones…

First thing first, we have to understand that the AKG-Telefunken AG GmbH ELA-M 250 & to the ELA-M 251E microphones were not the “All Around” microphones like the AKG C-12, AKG C-12 VR, AKG-Siemens SM-203, AKG C-24, AKG Perception 820…

If the ELA-M 250/251E were “All Around” microphones as any other AKG Microphones they will had the 200MΩ Grid-leak Resistor, not the 8MΩ (AKG-Telefunken AG GmbH ELA-M 250 with AC701K) or nether the 30MΩ (AKG-Telefunken AG GmbH ELA-M 251E with 6072 – 12AY7) …

But, as I wrote before, Siemens, the leading Co. of the Telefunken AG GmBH Trast (group of companies) holded a grange against Neumann, so Siemens forced the AKG to make the ELA-M 250 & 251E as Anti-Neumann U-47 & M-49 microphone(s)…

So, both of these microphones (the AKG-Telefunken AG GmbH ELA-M 250 & the AKG-Telefunken AG GmbH ELA-M 251E microphones…) had been designed and made especially to be as an “One trick pony, but a good one”…

They are especially well made nearly "magical" for female radio speakers, female singers – songwriters…

In other words they are the “Next Diva’s best microphone choice” as they are working pretty “magical” with the female voice register(s) of any wannabe Lara Fabian, Rihanna, Celine Dion, Christina Aguilera, Demi Lovato …

So yeah, if you want an “One trick pony” microphone for female radio speakers, female soprano singers only or for mandolin players, violinists or for drums overheads don’t change anything, because even the bright sound / tone anemic Warm Audio WA-251 it is good enough “go too” for that…

Save you money, save your time, save your energy for the next best microphone, whatever it is, a condenser U-47 type microphone for male voices, a ribbon microphone for brass instruments, a dynamic microphone for your guitar – bass speaker cabinets, for your drums set etc. etc. etc.

In other words: “You can pick up your new (microphone) G.A.S. poison”…

But tell me whatever happens if this situation does not exist…

Tell me whatever happens if you are not a female radio speaker?

Tell me whatever happens if you are not a wannabe next Diva female soprano singer?...

Tell me whatever happens if you are not a worldwide “hit record” sound engineer – record producer with sexy female singers to make their “catwalk” in your studio?...

Tell me whatever happens if you are not a mandolin player or a violinist, tell me whatever happens if you are not a drummer?...

Hell, tell me whatever happens if you are not a “castrato” tenor?...

Well, in all of these situations we will have to consider that any Cathode Biased ELA-M 250 / ELA-M 251E microphone has 4 main filters…

1. The Combination Between the capsule capacitance and the grid-leak resistor as a Low-Cut / High Pass Filter…

2. The Combination between Cathode Resistor and Cathode Bypass Capacitor as a Low-Cut / High Pass Filter……

3. The Treble Cut Snubbing Anode Bypass Capacitor as a High Cut to cut-off the highs…

4. The Combination Between the valve’s Ra with the capacitance of the coupling Capacitor and the impedance of the output transformer, which all of this combination determinate the F.R. slop…

So, let’s see some of “my” Mods…

1. ECC81 – 12AT7 valve @ 120 DC Volts Vb, 100KΩ Anode Resistor, 2.7KΩ Cathode Resistor, 22μF Cathode Bypass Capacitor …

Well, well, well, surprise – surprise – surprise…

This mod has been done firstly by the Swiss Boutique P2P Microphone Company BSA Microphones for their BSA ELAM 250 Microphone (Price: CHF 2,985.00 aka €3,250.00) …

After BSA Microphones this same mod. has been done by the Telefunken Electroacoustik USA for their Alchemy Series TF51 (Price: $1,995.00 aka 2.399 €)...

How do I know it?...

I know it because I had read this Article – Review by Brian Fox of Fox Audio Research:

The Telefunken AR-51

Review by Fox Audio Research (part 1)

&

The Telefunken AR-51

Review by Fox Audio Research, Cont'd... (part 2)

So, by simply changing only the valve in the Warm Audio WA-251 (888 €) to the ECC81 / 12AT7 Gold Balanced JJ (€34,33) plus the changing of the Cathode Resistor to 2,7k RES-0,6W (€0,19) I can have an economical “upgrade” over € 1.511 to my pocket and off curse a sonically “upgrade” over the Alchemy Series TF51 (Price: $1,995.00 aka 2.399 € )

Now, let’s add the 200M, 2W (€0,21) grid-leak resistor in to the game…

Immediately everybody could tell that this Grid-leak Resistor value plus the Cathode Resistor – Cathode Bypass Capacitor value combination “look like” the AKG C-24 Stereo Microphone (EUR 31,570.39) with the only difference will be, that now we use the proper tube…

Well, I think that I can “take” these mods. to the Warm Audio WA-251 as an option and spend the rest of these € 30.688 EUR to hookers and drugs…

thanks so much.. i almost get there
can u explain where to put Cathode Resistor to 2,7k RES-0,6W (just for make sure) because i think it will be replacing resistor number 4 on my picture, is that correct?

and “Now, let’s add the 200M, 2W (€0,21) grid-leak resistor in to the game” is that placed to the number 1 on my picture?

i will check the PSU later to mod them

 

[Luckyadnan]

Have you tried an other preamp? Presonus has quite low input impedance of 1.3k. In some spec sheets it's written that wa251 needs at least 2k.

i change the Opamp to BB OPA4134 , i think its 2k input impedence.. but i can straight tonuse alctron mp73eqv2 . anyway are u sure it needs 2k? because the output impedence i read is 200ohm

 

[Luckyadnan]

@Luckyadnan, @Khron, @pasarski

A little bit of talk-to-talk “just to put the record straight” about these mods that I suggested…

I never owned or brought any Warm Audio product, as I never owned or brought any Telefunken Elecroacoustik USA product, as I will never own or buy any product from any major Chin-o-Canadian-American-whatever the fukk “globalization” mass production companies, because as it is odiously they “fukk it up” by “Cutting Coners” any time that they try to copy on or to be said more clearly to steal on from the heritage and the tradition of historical European Microphone Companies like AKG, like Neumann, like Schoeps…

This will be as stupid to me as if I had bought any Japanese Sony, Nikon, Canon Digital cameras and wait from any of them afterwards, to take pictures as good as my photos that I take with my "Made in Germany" Leica SL3 digital camera, regardless of any lens I should use ...

But let’s go back to the AKG-Telefunken AG GmbH ELA-M 250 & to the ELA-M 251E microphones…

First thing first, we have to understand that the AKG-Telefunken AG GmbH ELA-M 250 & to the ELA-M 251E microphones were not the “All Around” microphones like the AKG C-12, AKG C-12 VR, AKG-Siemens SM-203, AKG C-24, AKG Perception 820…

If the ELA-M 250/251E were “All Around” microphones as any other AKG Microphones they will had the 200MΩ Grid-leak Resistor, not the 8MΩ (AKG-Telefunken AG GmbH ELA-M 250 with AC701K) or nether the 30MΩ (AKG-Telefunken AG GmbH ELA-M 251E with 6072 – 12AY7) …

But, as I wrote before, Siemens, the leading Co. of the Telefunken AG GmBH Trast (group of companies) holded a grange against Neumann, so Siemens forced the AKG to make the ELA-M 250 & 251E as Anti-Neumann U-47 & M-49 microphone(s)…

So, both of these microphones (the AKG-Telefunken AG GmbH ELA-M 250 & the AKG-Telefunken AG GmbH ELA-M 251E microphones…) had been designed and made especially to be as an “One trick pony, but a good one”…

They are especially well made nearly "magical" for female radio speakers, female singers – songwriters…

In other words they are the “Next Diva’s best microphone choice” as they are working pretty “magical” with the female voice register(s) of any wannabe Lara Fabian, Rihanna, Celine Dion, Christina Aguilera, Demi Lovato …

So yeah, if you want an “One trick pony” microphone for female radio speakers, female soprano singers only or for mandolin players, violinists or for drums overheads don’t change anything, because even the bright sound / tone anemic Warm Audio WA-251 it is good enough “go too” for that…

Save you money, save your time, save your energy for the next best microphone, whatever it is, a condenser U-47 type microphone for male voices, a ribbon microphone for brass instruments, a dynamic microphone for your guitar – bass speaker cabinets, for your drums set etc. etc. etc.

In other words: “You can pick up your new (microphone) G.A.S. poison”…

But tell me whatever happens if this situation does not exist…

Tell me whatever happens if you are not a female radio speaker?

Tell me whatever happens if you are not a wannabe next Diva female soprano singer?...

Tell me whatever happens if you are not a worldwide “hit record” sound engineer – record producer with sexy female singers to make their “catwalk” in your studio?...

Tell me whatever happens if you are not a mandolin player or a violinist, tell me whatever happens if you are not a drummer?...

Hell, tell me whatever happens if you are not a “castrato” tenor?...

Well, in all of these situations we will have to consider that any Cathode Biased ELA-M 250 / ELA-M 251E microphone has 4 main filters…

1. The Combination Between the capsule capacitance and the grid-leak resistor as a Low-Cut / High Pass Filter…

2. The Combination between Cathode Resistor and Cathode Bypass Capacitor as a Low-Cut / High Pass Filter……

3. The Treble Cut Snubbing Anode Bypass Capacitor as a High Cut to cut-off the highs…

4. The Combination Between the valve’s Ra with the capacitance of the coupling Capacitor and the impedance of the output transformer, which all of this combination determinate the F.R. slop…

So, let’s see some of “my” Mods…

1. ECC81 – 12AT7 valve @ 120 DC Volts Vb, 100KΩ Anode Resistor, 2.7KΩ Cathode Resistor, 22μF Cathode Bypass Capacitor …

Well, well, well, surprise – surprise – surprise…

This mod has been done firstly by the Swiss Boutique P2P Microphone Company BSA Microphones for their BSA ELAM 250 Microphone (Price: CHF 2,985.00 aka €3,250.00) …

After BSA Microphones this same mod. has been done by the Telefunken Electroacoustik USA for their Alchemy Series TF51 (Price: $1,995.00 aka 2.399 €)...

How do I know it?...

I know it because I had read this Article – Review by Brian Fox of Fox Audio Research:

The Telefunken AR-51

Review by Fox Audio Research (part 1)

&

The Telefunken AR-51

Review by Fox Audio Research, Cont'd... (part 2)

So, by simply changing only the valve in the Warm Audio WA-251 (888 €) to the ECC81 / 12AT7 Gold Balanced JJ (€34,33) plus the changing of the Cathode Resistor to 2,7k RES-0,6W (€0,19) I can have an economical “upgrade” over € 1.511 to my pocket and off curse a sonically “upgrade” over the Alchemy Series TF51 (Price: $1,995.00 aka 2.399 € )

Now, let’s add the 200M, 2W (€0,21) grid-leak resistor in to the game…

Immediately everybody could tell that this Grid-leak Resistor value plus the Cathode Resistor – Cathode Bypass Capacitor value combination “look like” the AKG C-24 Stereo Microphone (EUR 31,570.39) with the only difference will be, that now we use the proper tube…

Well, I think that I can “take” these mods. to the Warm Audio WA-251 as an option and spend the rest of these € 30.688 EUR to hookers and drugs…

“Now, let’s add the 200M, 2W (€0,21) grid-leak resistor in to the game…”

anyway are u sure its 200M, 2W? because i open the link and its written 220k 2W

 

[pasarski]

i change the Opamp to BB OPA4134 , i think its 2k input impedence.. but i can straight tonuse alctron mp73eqv2 . anyway are u sure it needs 2k? because the output impedence i read is 200ohm

The rule of thumb is that the preamps input impendance should be 10x the output impedance of a microphone.

I don't know that preamp nor the mod, might change the input impendance or not, depends on the circuit I guess.

Also, I wouldn't trust WA's published 200ohm spec 100%.

 

[Accelerator]

@Luckyadnan

thanks so much.. i almost get there
can u explain where to put Cathode Resistor to 2,7k RES-0,6W (just for make sure) because i think it will be replacing resistor number 4 on my picture, is that correct?

and “Now, let’s add the 200M, 2W (€0,21) grid-leak resistor in to the game” is that placed to the number 1 on my picture?

i will check the PSU later to mod them

Yes, I’m pretty sure as you can see by the AKG Schematics & Service Manuals that the Grid-leak resistor in any AKG C-12 VR, AKG-Siemens SM-203, AKG C-24, AKG Perception 820 microphone is a 200MΩ Grid-leak Resistor and the legendary AKG C-12 microphone has even higher 250MΩ Grid-leak Resistor…

Off course back in the late ’50’s – early ‘60’s time they didn’t have 2-watt Resistors nether as P.S.U. filter resistors and AKG used 0.5 watt P.S.U. filter resistors and 0.2 watt resistors for the rest of the circuit…

The Cathode Resistor as it is obiously it is connected with the Cathode of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 3 or the pin 8 (cathodes) are connected with the 1.8 KΩ Cathode Resistor (Typical AKG-Siemens SM-203, AKG-Telefunken ELA-M 251E) and then to replace this Cathode Resistor with the 2.7 KΩ Cathode Resistor and off course to replace the 6072-12AY7 tube with the ECC81 / 12AT7 Gold Balanced JJ (€34,33)…

In the same way the Grid-leak Resistor as it is obiously it is connected with the Grid of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 2 or the pin 7 (Grids) are connected with the 30 MΩ Grid-leak Resistor and then to replace this Grid-leak Resistor with the 200 MΩ Grid-leak Resistor…

 

[Luckyadnan]

@Luckyadnan

Yes, I’m pretty sure as you can see by the AKG Schematics & Service Manuals that the Grid-leak resistor in any AKG C-12 VR, AKG-Siemens SM-203, AKG C-24, AKG Perception 820 microphone is a 200MΩ Grid-leak Resistor and the legendary AKG C-12 microphone has even higher 250MΩ Grid-leak Resistor…

Off course back in the late ’50’s – early ‘60’s time they didn’t have 2-watt Resistors nether as P.S.U. filter resistors and AKG used 0.5 watt P.S.U. filter resistors and 0.2 watt resistors for the rest of the circuit…

The Cathode Resistor as it is odiously it is connected with the Cathode of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 3 or the pin 8 (cathodes) are connected with the 1.8 KΩ Cathode Resistor (Typical AKG-Siemens SM-203, AKG-Telefunken ELA-M 251E) and then to replace this Cathode Resistor with the 2.7 KΩ Cathode Resistor and off course to replace the 6072-12AY7 tube with the ECC81 / 12AT7 Gold Balanced JJ (€34,33)…

In the same way the Grid-leak Resistor as it is odiously it is connected with the Grid of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 2 or the pin 7 (Grids) are connected with the 30 MΩ Grid-leak Resistor and then to replace this Grid-leak Resistor with the 200 MΩ Grid-leak Resistor…

but the link u send here is not 200M, are u sure about that item on your link? do u have 250M link too?

 

[Accelerator]

@Luckyadnan​

but the link u send here is not 200M, are u sure about that item on your link? do u have 250M link too?

Here is the link for the TR15G200MFNES Thick Film Resistors 1.5W 200Mohms 1% 200ppm with Qty: Minimum 1

Here is the link for the TR10F200MFKRS Thick Film Resistors 1.0watt 200Mohms 1% 100ppm with Qty: Minimum 1

Here is the link for the MOX300002006FE Metal Oxide Resistors 200M OHM 1% 100PPM 1/2W with Qty: Minimum 1

And finally

Here is the link for the MGM3FT200M Thick Film Resistors RES, MG, 3W, 200 Mohm, 1% with Qty: Minimum 1000

 

[Khron]

@Luckyadnan​

Here is the link for the TR15G200MFNES Thick Film Resistors 1.5W 200Mohms 1% 200ppm with Qty: Minimum 1

Here is the link for the TR10F200MFKRS Thick Film Resistors 1.0watt 200Mohms 1% 100ppm with Qty: Minimum 1

Here is the link for the MOX300002006FE Metal Oxide Resistors 200M OHM 1% 100PPM 1/2W with Qty: Minimum 1

And finally

Here is the link for the MGM3FT200M Thick Film Resistors RES, MG, 3W, 200 Mohm, 1% with Qty: Minimum 1000

Why 0.5-3W resistors though, costing 4-9eu PER PIECE?

What's wrong with two of these in series (assuming there's enough physical space)?

https://eu.mouser.com/ProductDetail...=sGAEpiMZZMtlubZbdhIBIFho3SHfDXStYcUMeQ6Zhmc=

Well, not that any of those (pricey) suggestions is particularly compact anyway...

 

[Accelerator]

@Khron

Why 0.5-3W resistors though, costing 4-9eu PER PIECE?

What's wrong with two of these in series (assuming there's enough physical space)?

https://eu.mouser.com/ProductDetail...=sGAEpiMZZMtlubZbdhIBIFho3SHfDXStYcUMeQ6Zhmc=

Well, not that any of those (pricey) suggestions is particularly compact anyway...

Because Luckyadnan demands that one 200MΩ resistor “that rules them all…”, although that he knows that he can use 2 * 100MΩ resistors wired in series and get the same 200MΩ resistance value…

As for the Mauser’s prices after all, I’m not responsible in any way for the Mauser’s high prices…

For a UK – Europe Alternative browser for the passive components you can look at Farnell UK…

https://uk.farnell.com/c/passive-components/resistors-fixed-value/through-hole-resistors

 

[Luckyadnan]

@Khron

Because Luckyadnan demands that one 200MΩ resistor “that rules them all…”, although that he knows that he can use 2 * 100MΩ resistors wired in series and get the same 200MΩ resistance value…

As for the Mauser’s prices after all, I’m not responsible in any way for the Mauser’s high prices…

For a UK – Europe Alternative browser for the passive components you can look at Farnell UK…

https://uk.farnell.com/c/passive-components/resistors-fixed-value/through-hole-resistors

thankyou so much, its really help.. now i need to find where is the 30M Ohm resistor, because when i try to match the resistor value on color calculator, nothing was 30M resistor.

 

[Accelerator]

@Luckyadnan

thankyou so much, its really help.. now i need to find where is the 30M Ohm resistor, because when i try to match the resistor value on color calculator, nothing was 30M resistor.

“Follow” the attached schematic of the original AKG-Telefunken ELA-M 251E circuit to find it where it is, not only the resistor’s colors, because we don’t have in any way any true and real evidence that Warm Audio stays so much as “tutorials” to the original AKG-Telefunken ELA-M 251E values for their WA-251 clone microphone as they wrote that their microphone it is:

“True Recreation Of A Studio Classic Revered For Warm And Balanced Tones”…

What the Fukking Hell, we are talking about the same company that they use 5751 pre-amp tubes in a CCDA circuit and after that they dare to “name” their microphone as WA-47 and much more than that, they dare to “claim” in total madness that their WA-47 is or could ever be or will be in any way the:

“Authentic Reproduction Of The Most Coveted Mic For Timeless Studio Sound”….

What a joke man it is this company, what a joke!...

The Cathode Resistor as it is obiously it is connected with the Cathode of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 3 or the pin 8 (cathodes) are connected with the 1.8 KΩ Cathode Resistor (Typical AKG-Siemens SM-203, AKG-Telefunken ELA-M 251E) and then to replace this Cathode Resistor with the 2.7 KΩ Cathode Resistor and off course to replace the 6072-12AY7 tube with the ECC81 / 12AT7 Gold Balanced JJ (€34,33)…

In the same way the Grid-leak Resistor as it is obiously it is connected with the Grid of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 2 or the pin 7 (Grids) are connected with the 30 MΩ Grid-leak Resistor and then to replace this Grid-leak Resistor with the 200 MΩ Grid-leak Resistor…

 

[Khron]

The Cathode Resistor as it is odiously it is connected with the Cathode of the valve

https://en.wiktionary.org/wiki/odious

Perhaps you meant "obvious" / "obviously"?

 

[Accelerator]

@Khron​

https://en.wiktionary.org/wiki/odious

Perhaps you meant "obvious" / "obviously"?

Yup, my typo as I wrote it two times at late night and my tired eyes didn’t help me too much, but you’ve got the point…

 

[pasarski]

thankyou so much, its really help.. now i need to find where is the 30M Ohm resistor, because when i try to match the resistor value on color calculator, nothing was 30M resistor.

I thought you already found the 30meg. It's the one connected to the Teflon post.

 

[Luckyadnan]

@Luckyadnan

“Follow” the attached schematic of the original AKG-Telefunken ELA-M 251E circuit to find it where it is, not only the resistor’s colors, because we don’t have in any way any true and real evidence that Warm Audio stays so much as “tutorials” to the original AKG-Telefunken ELA-M 251E values for their WA-251 clone microphone as they wrote that their microphone it is:

“True Recreation Of A Studio Classic Revered For Warm And Balanced Tones”…

What the Fukking Hell, we are talking about the same company that they use 5751 pre-amp tubes in a CCDA circuit and after that they dare to “name” their microphone as WA-47 and much more than that, they dare to “claim” in total madness that their WA-47 is or could ever be or will be in any way the:

“Authentic Reproduction Of The Most Coveted Mic For Timeless Studio Sound”….

What a joke man it is this company, what a joke!...

The Cathode Resistor as it is obiously it is connected with the Cathode of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 3 or the pin 8 (cathodes) are connected with the 1.8 KΩ Cathode Resistor (Typical AKG-Siemens SM-203, AKG-Telefunken ELA-M 251E) and then to replace this Cathode Resistor with the 2.7 KΩ Cathode Resistor and off course to replace the 6072-12AY7 tube with the ECC81 / 12AT7 Gold Balanced JJ (€34,33)…

In the same way the Grid-leak Resistor as it is obiously it is connected with the Grid of the valve, so it will be a little bit tricky for you that you have to look undersides at the tube base and see if the pin 2 or the pin 7 (Grids) are connected with the 30 MΩ Grid-leak Resistor and then to replace this Grid-leak Resistor with the 200 MΩ Grid-leak Resistor…

thankyou so much, the item for this mod is on the way!

 

[Luckyadnan]

WA251 MOD
- 200Meg resistor
- 1uF Capacitor

the sound is more harsh, the high sparkle is gone.

any idea? @Accelerator @Khron

is that if i use 12at7 mod will make a sound smoother?

what different is make when changing b+ to 120v?

anyway mr @pasarski really help me a lot



https://cdn.imagearchive.com/groupd...0551379ed7e4e5e054d2178bd2d1d28fb24aa1666af64

 

[pasarski]

what different is make when changing b+ to 120v?

It'll change the tube bias and polarization voltage. Now that I know you have a guy doing the soldering for you and I assume he knows electronics and the dangers of working with high voltages you can change the B+ and see what it does to the sound. Don't expect wonders. Either add a resistor or change a zener/the zeners. Two 60V zeners or what ever combination that gives 120V. Don't forget to tap the polarization voltage for patterns after the resistor if you go that way, your patterns will be off if you don't.

There's no easy way to explain the procedure, but if your guy knows electronics it should be easy for him following what I wrote.

Good luck!

More info:

https://groupdiy.com/threads/apex-460-power-supply-mod-d5-d6.65159/

 

[Accelerator]

@Luckyadnan & pasarski​

WA251 MOD
- 200Meg resistor
- 1uF Capacitor

the sound is more harsh, the high sparkle is gone.

any idea? @Accelerator @Khron

is that if i use 12at7 mod will make a sound smoother?

what different is make when changing b+ to 120v?

anyway mr @pasarski really help me a lot

Which tube do you have this time in your microphone?...

How much voltage (value) do you have at this time at your P.S.U. as HT Vb and how much voltage (value) do you have at this time at the pin 1 (Anode) of your tube?...

Are you sure that you properly connect the 200 MΩ resistor(s) comp. from pin 2 (Grid) to Ground?...

Do you have a certificated electronic engineer who can doing the soldering job for you and you can assume that he knows electronics, that he knows to follow properly the schematics and that he knows the dangers of working with high voltages you can change the B+ and see what it does to the sound?...

As I wrote to you before the «30MΩ to 200 MΩ Mod.» it is NOT the Premiere Mod. that you have to do, as changing the grid-leak resistor value you gain more extending bass response, but you also gain more Gain aka your microphone will sound more “Modern” or harsh…

This mod. comes as a side-change if you go from the 6072 – 12AY7 tube (μ Factor = 40) to the ECC82 – 12AU7 tube (μ Factor = 18) to get back up some of the gain that you lose by the change of the μ Factor of the tubes…

So the Premiere Mod. in any time is to choose firstly the “proper tube” that you like to work with it, then to properly re-biasing this tube with the proper Anode Resistor (RL) value to the proper Cathode Resistor (CR) value and the proper Cathode Capacitor value and then to mod. the Grid-leak Resistor if you think that you need it so…

Don't expect wonders.

Here are 2 F.R. pictures of the same RK-12 Capsule in 2 different 251 clone microphones…

The first one F.R. picture of the same RK-12 Capsule comes from a properly biasing 251 clone by a modified Apex microphone by Brian Fox of Fox Audio Research…

The 12+ and 251+ PE

https://foxaudioresearch.ca/CT12.htm

The second one F.R. picture of the same RK-12 Capsule comes from your (original) Warm Audio 251 microphone…

https://warmaudio.com/wa-251

As you can see there is a significant difference in these 2 Frequency Responses of the same RK-12 Capsule in 2 different 251 clone microphones and by the “traditional” change from the 6072 – 12AY7 to ECC81 – 12AT7 or even better to ECC82 – 12AU7 tube you can go to this “extended flat down” Frequency Response without to go to the “extreme to extreme” E88CC – 6922 tube which doesn’t have the same basing of the 12A*7 “family” and you will have some reliability problems with this tube in the ultra-high-impedance world of condenser microphones and without to use any led – diode solution as Cathode biasing, otherwise I could easily wrote to you:

“Wire 2 diodes 0.6 Volts in series from the pin 3 (Cathode) of your 6072 – 12AY7 in reverse pollarisation to ground and you will have a “Fixed Bias” like biasing response....”

There are many tricks under the belt in electronics and physics or if you like even better:

“There many ways to climb a mountain” as the legendary Miyamoto Musashi wrote, but in any time you have to consider that:

“There is no a free dinner for all the things in your life, you gain some – you lose some…”

 

[banio1208]

Did anyone have a issues with PCB in Warm 251?