Mic Input tranny replacement

[Guest]

Having read the Meta on mics, could I get a concensus on what a good replacement mic input transformer suitable for an ADK GC1 Fet mic? I think its just another 797 audio clone in fact the literature soughta suggests its A-51 without the pad and external roll off switch. There is a internal roll off switch. The capsule looks like its really well made. I did a A/B with a NT1 and the NT1 had more output, but the ADK sounded much better to me.

Also does anyone have a circuit for this ADK mic please?

I've put this post up because theres just too much info to wade through on the Meta, just some relevant info would be greatly appreciated from those who have already gone down this path.

My thinking is, maybe just change the tranny and the capsule (Peluso C12 capsule?) and I've got something quite decent.

Thanks.

 

[PRR]

> I did a A/B with a NT1 and the NT1 had more output, but the ADK sounded much better to me. ...My thinking is, maybe just change the tranny and the capsule (Peluso C12 capsule?) and I've got something quite decent.

Not to throw dirt on your thinking, but: I got a Honda Accord. It is really a very good car. If I just change the engine and suspension (Ferrari V-12 Testarossa?) it might be quite decent.

I mean: even if a $200-list mike has a transformer, if you change the tranny and the capsule then all that is left is a $4 body and $1 worth of FET and resistors. Can't you buy a whole decent mike as cheap or cheaper than you can buy loose parts?

"More output" is not necessarily good. (Or not in mikes: Ferarri power-output in my Honda might be more gooder.) Output level is good if you favor low-gain preamps and record weak sources; but I use cheap preamps with softer acts and mikes much weaker than large-diaphragm condensers and have not yet run out of gain. I can't remember the last time I maxed-out a gain knob, except in checking for background noise.

OK, your asked question: without knowing the circuit or the internal space (the GC1 does not seem to be widely sold; and I never met one) then nobody can really answer the question. Some mikes use 1:1 transformers, some use 7:1, many low-price mikes are transformerless and a tranny-out circuit would be a complete re-design, not a plop-and-play proposition.

 

[Guest]

Have you ever looked at an old U87? There's not much to it. The best thing about them is the capsule and the transformer. The chinese have copied these mics with budget electronic parts, by todays standards that is, but still, they are good designs which they have borrowed.

I don't care about the output either! I bought the mic with the lower output didn't I, cause it sounded better!

You seem to miss my point, the critical factor would have to be the capsule and the transformer I would have thought. I bet if I put a Neumann capsule in it with a high spec transformer it would sound better than an old U87? Thats not cost effective so I'd settle for a Peluso Capsule and new transformer which brings me back to my original question.

 

[Marik]

[quote author="HG"]
You seem to miss my point, the critical factor would have to be the capsule and the transformer I would have thought. I bet if I put a Neumann capsule in it with a high spec transformer it would sound better than an old U87? Thats not cost effective so I'd settle for a Peluso Capsule and new transformer which brings me back to my original question.[/quote]

PRR missed the point??? That's something new!
On the other hand I am confused. In your first message you are saying that the mic has a good capsule and sounds fine, then you are saying that you'd like to use Peluso capsule. Why? Did you hear this capsule? Do you like it better?
Also, what is "cost effective" in your understanding?

Oh yeah, back to PRR's question. What is the transformer ratio?

 

[Guest]

I assume the guys who read this post and can help me, have read the Meta on Mics. Sorry if you haven't.

Most of the chinese fet condensers come out of the 797audio factory or have some sort of association with them in terms of parts etc, ie its a generic mic.

The dorsey Fet mod has pics etc, my mic, the ADK GC1 falls into that category as do alot of other brands which have been sucessfully modded in their vast and various incarnations. Some of those ppl would have a good idea as to what input tranny would suit this mic as they have the same mic as me and probably have faced this very question themselves.

Sorry Marik, but I didn't mean to say that the capsule sounds fine in the 1st post.

However, I did mean it when I wrote that I want to replace it with a better capsule. I hope thats clear now. I'm open to suggestions, as my first post clearly implies.

If it costs say $500 USD for an AKG C12 capsule then I probably wouldn't be interested. Thats what I mean when I use the term "cost effective". If I could get a cheaper Blue capsule or someone knows another really good one then great?

Actually, this whole thing was not my idea and was spawned by a conversation with a mate (the former Technical Director of Air Studio's and EMI) who was my next door neighbour for many years. He can't believe how ppl still use these old Neumanns and reckons the newer mics are vastly better in terms of manufacture and design etc. He was the one who actually suggested stick a high quality capsule in cheap chinese mic and it will sound better than a 20 year old U87 that everyone pays homage to. If you think about it, it makes sense.

 

[Gus]

You missed some stuff in the long metas. An easy thing to do.

Do you own the microphone? If so look at the capsule 18 screws and a brass hold down ring, Most likly a soundking or feilo 32mm capsule
wonder http://www.manleylabs.com/containerpages/refcardioid99.html

14 screws and plastic hold down ring could be a 797 or even one of the soundkings at 34mm

18 screws and a plastic ring a superlux.

PCB two transistors one a 170 and the other a pnp and a 2:1 transformer. Look at the mxl 67,2001,cascade,luna and other standard china FET PNP circuit schematics

What to change has been covered in the threads.

Post a picture that will help. I have not been inside an ADK but it sounds like it might be like a 2001v67 circuit.

Another thing most china capsules do not sound as good as a real neumann k67 k87 capsule. I have alot of china midrophone and some very godd microphone and good capsules. Most of the time a good capsule is going to cost you good money $500 to $1,000 USA

 

[Guest]

I think the point here is that when you buy a mic, you are paying mostly for capsule and transformer.... If you take those out and put in new ones, why not just build a new mic from scratch, since the majority of chinese mics are rips of older designs that are readily available.

 

[pucho812]

PRR missed the point??? That's something new!

:shock:

HG applogize to prr right now!!!!

Anyway from what I gather from your post you own the mic or want to buy it and mod it and although are pleased with the sound you feel it could sound better. In fact you did an A/b test with a rode nt1 and liked the ADK over the rode. You are thinking that by replaceing the capsule and the trannie the sound will improve. I do think it would sound different but not necessarly sure if it would sound better. Remember better is an opinion and not to beat a dead horse but what is your sound source?
Just cause the mic sounds good doesn't mean it will work in the whole context of what you are working on.
Prr is right in saying most expensive part of a mic is the trannie and capsule. a good blue capsule will cost you around 500.00 and a peluso will be around 100-200. I can only ask you this if you think the sound is pleasing to your ears why **** with it at all?

 

[Guest]

I paid peanuts for the 2 mics new. And for the money, 1/3 the price of a NT1, and it sounds better than a Rode. But thats not saying much is it? To replace the capsule and tranny takes 30 minutes if that, and the result could be stunning, without any frigging around.

I can upgrade the circuit board at a later date.

How do I post pics?

 

[Gus]

the stock capsule might be very usable.

 

[Guest]

The capsule has 16 screws and is 32mm. I read the ADK forums and they seem to suggest that its an identical ADK A51 design but with cheaper circuit board components and probably a cheap transformer.

I like the Dorsey mod too. Anyone here making the pcb's?

 

[Guest]

ok I've acquired a Neumann U67 capsule in good working condition from another Studio which I pick up tomorrow. H

e reckons the only issue would be impedence of the U67 being a bit higher. But the transformer should should handle it right?

I'm gonna hot glue it on! hehe...I can just see you guys screwing your faces up!

 

[soundguy]

I know you seem intent on upgrading this junky mic you have and you know, not for nothing, but if you have a real k67 capsule, why not build a real mic out of the thing?

dave

 

[Gus]

HG

I would guess you your posts are trolls.

 

[Guest]

I will change the mic to the dorsey Fet project, and yes your right in what you say.

But I'm still gonna shove the U67 capsule in it and see what it sounds like without the upgrade first and post the results for all to hear. I have two adk mics, so I'll record with both after upgrading one of them and post the mp3's so we can all hear if it makes a significant difference. I run PTLE via Digimax adat etc so I have a high spec setup.

It will happen tomorrow actually.

How do I post pictures and mp3's? Sorry but I'm a noob.

 

[tubejay]

To post pictures, open up a free account at www.photobucket.com and copy the file that starts with and paste it in your text, and it will automatically load up. You'll know what I mean after you upload the file to photobucket.

You need a place to host your .mp3s as well. Check out www.garageband.com or something like that for a service that will do that for you. I'm pretty sure they are free as well. Then just copy and paste the location of the file into here and it will automatically pop up as a link.

I agree, if you really have a K67, build a G7 or something like that. Or heck, build a U67.

 

[Guest]

Here are some photo's, sorry its not very sharp but I only have a phone camera

 

[zebra50]

whatever you do, remember to salvage the 1 gig resistors!

 

[Gus]

I have seen that circuit in a sam ash ld 1. Standard china 170 fet, PNP transistor stage with an internal high pass roll off switch. Yellow caps look like PETS, 2:1 output transformer

Look for the 2001/v67 schematic

 

[Guest]

ok I put the k67 capsule in and I get lost of humm! Is it an impedance miss match? Help please!!!