Rode Classic 1 capsule, tube and output cap upgrade?

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Carl Cress

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I have a client that doesn't feel his Rode Classic Mk1 is all it can be and has asked me for advice in regards to modifying or upgrading it for him. I have suggested upgrading to Eric Hiesermans HK67 and finding a quite high quality 6072. I'm wondering if anyone has had any experience and or success with this. Any recommendations?
 

Gus

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Found this
https://www.gearslutz.com/board/geekslutz-forum/917788-rode-classic-psu-schematics.html

What do you mean by "is all it can be" What does the person not like about the sound? IMO that's where you start.

I see a few things you can do

Why would you put a K67 like capsule in that microphone? Look at the schematic.

You might get a bunch of web nonsense like change the capsule. if you know what you are doing you can adjust the circuit for the stock capsule before changing the capsule.

One part looks way to high in value to me in the schematic.

You might want to add a part.

Changing a tube is often something worth trying.

Do you have test gear to measure things?
 

Carl Cress

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Hi Gus, thanks for getting back to me. I will get a better understanding of his dislikes and reply.

In the meantime, I'm wondering what you mean by a component being too high of value?
 

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Tim Campbell

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With Rode mics I have found that changing the capsule makes the biggest improvement in sound quality. Rode capsules just sound poor. I'm not sure a K67 would help as the top end is not particularily smooth and the Rode preamps are extremely uncolored so they don't flatter the capsule. A K47 or good CK12 would most likely sound better.
 

Recording Engineer

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I agree with Tim on Rode's capsules... I seems to like stock Rode mics best as their preamplifiers seem to mask  their capsule short-comings or brings out the best of their capsules; however you look at it!
 

LevinGuitar

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You can use a better quality 22uf electrolytic cap, try some audio grade ones and keep what you like most. Maybe you can even fit a MKT of same capacitance (100v would be enough I guess). A good C5 will also make a change.

But with Tim's capsule, is still nessesary that capacitance for C7?
 

Andresound

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Will look for a better quality 22uf. Will also look at C5. The output xtmr is a jensen and not a T14. Maybe has something to do with the choice for C7?
 

Banzai

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Only purpose to use 22uf would be to move the bass resonance into inaudible frequencies. Try a 1uf to hear the difference.
 

ingaudio

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You have to replace :
C2 with Wima FKP2 1000pF/250v or 400v or 630v (same case)
C7 with Elna Silmic II 22uF/100v or Nichicon Fine Gold 22uF/100v
 

Andresound

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Thanks Banzai. I mentioned in a previous thread, that I that I tried a Solen 5.6uf (I can’t remember), and ended up going back to the 22uf. Would bypassing with a 10n polystyrene, not improve things, or will this just complicate phase behaviour? I am not an EE, so these matters are above my pay grade. Maybe just stop fiddling and keep using the mic as is. D
 

Banzai

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5.6uf is still big. To hear a real difference go down to around 1uf. Will give a noticeable lowend boost. Don't bypass, just replace with smaller value.

U67 and 251 used elco for coupling capacitors and both sound great. Ingaudio's recommendation of Silmic II is a good one. They're great for cathode bypass. Never tried for coupling.

Maybe just stop fiddling and keep using the mic as is. D
If you're happy with it, then yes ;)

There's no right or wrong. If it sounds good to you, then it is good. Doesn't matter how it looks on paper (or what anyone else thinks).
 

ingaudio

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I have an audio lab since 80s' well know in Tuscany ( Italy), my customers are Studio Recordings, Musicians and Hi-fi enthusiasts
When I have to recap mics ( or other audio devices both modern or vintage) the rule is film foil POLYPROPYLENE on the signal path if size allow it , otherwise POLYESTER ; if need big value I go to Elna Silmic II as first choice or Nichicon Fine Gold ( slightly smaller) as second choice.
An example of U87 with Wima FKP2 470pF / MKP2 1uF ( PIC1 original PIC2 recap)
 

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Andresound

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5.6uf is still big. To hear a real difference go down to around 1uf. Will give a noticeable lowend boost. Don't bypass, just replace with smaller value.

U67 and 251 used elco for coupling capacitors and both sound great. Ingaudio's recommendation of Silmic II is a good one. They're great for cathode bypass. Never tried for coupling.


If you're happy with it, then yes ;)

There's no right or wrong. If it sounds good to you, then it is good. Doesn't matter how it looks on paper (or what anyone else thinks).
Banzai, thank you for the info. I’m a little confused.., 5.6uf to1uf will give a “low end boost”? I was under the impression it would give the opposite effect?
 

Khron

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Banzai, thank you for the info. I’m a little confused.., 5.6uf to1uf will give a “low end boost”? I was under the impression it would give the opposite effect?

 

Andresound

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Khron, I did get that reading material. Thank you. I am busy trying to digest it!!! A little over my head (I am a hobbyist), but I appreciate the info.
 

Banzai

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Banzai, thank you for the info. I’m a little confused.., 5.6uf to1uf will give a “low end boost”? I was under the impression it would give the opposite effect?
Khron's link explains it in Figure 3 and Figure 4:

"If you need some bass boost, it's easily achieved by using a series capacitor. Using a 100µF cap gave a small but useful 1dB boost at 20Hz, and smaller values will provide boost at higher frequencies."

Difference between 0.5uf and 1uf capacitors is already very noticeable.
 
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