Ribbon Mic: RB500 vs APEX 205

[Violinist]

Right. I was aware about the Johnson noise generation principle etc. What it was not clear is: how it is possible that: with same motor and (as far as I've understood from what I read in internet) similar circuitry, the level of this noise is so important, when the elements between the mics (the 2 types I considered) are almost identical (I'm talking about the motor) and both they don't use any circuitry than a Transformer.

I'm aware that everything is put on the signal path generates intrinsically noise, even wires (thus: also Transformers), but I was wondered about: so loud noise.

I was not thinking to impedance mismatch, you put in highlight, where a big loss of signal of course deteriorates/worsens the S/N Ratio.

Based on your indications, I re-read your previous message related to your RB500 and I checked the Input Impedance of your Pre. Indeed I noticed that, indeed, their input impedance are too low to be matched with the 2k5 you have in your RB500.
So that, I was wondered that the author of that review had the same issue.

He has(had) a Aphex 1100, as declared, and I wanted to check its specs:
http://www.aphex.com/pdf/1100/Aphex_1100_specs_only_1pslip.pdf

What I found is: no indication about Z-In.

Thus: your suspects are full reality. At this point I think the author of that review couldn't check the mismatch: he had no indications that could warn him (it's my opinion, so I can wrong).

At this point I need to check the input impedance of my Board and to verify the necessity to buy or build a Buffer.

 

[abbey road d enfer]

So that, I was wondered that the author of that review had the same issue.

He has(had) a Aphex 1100, as declared, and I wanted to check its specs:
What I found is: no indication about Z-In.

Yes, that's quite surprising.
I've checked their other mic pres; their flagship 1788 has a low-ish input Z of 1.6k. That would produce an attenuation of 8dB.

 

[Kingston]

I can also report a case of two different transformers in two RB500's. I bought them maybe three years apart. The older one had hiss issues. Turns out it was indeed the transformer. The new one has a different transformer that resulted to roughly 8-12dB more level ie. roughly that amount less hiss. I didn't even go to details and just thought "screw this!" and got a Lundahl LL2913 ribbon mic transformer for both. Now they match.

But a word of advice from another Prodigy Pro member Rossi:

"The Lundahl ribbon tranny sounds fantastic, but it isn't particularly low noise as the primary resitance is a bit too high for the RB-500. The stock transformer is actually a bit lower noise - but it doesn't sound as nice."

(I guess he is talking about the newer transformer revision, because the old one was noisy as hell)

If you want the best transformer in the whole wide world for these mics, Marik is the guy.

By the way, here is a little DIY project somewhat similar in concept to the FEThead:
http://www.groupdiy.com/index.php?topic=5743.0

I also experimented with new ribbon material and corrugation for RB-500:
http://www.groupdiy.com/index.php?topic=39621.0

I'm not entirely happy with my re-ribboning. One of these days I'll try again. I only wish I had access to various aluminum foil thicknesses most suitable for this mic. Not sure the stuff I have is optimal. My corrugation rig & methods are also somewhat questionable.

 

[kepeb]

interesting to know about the versions... not sure which version but I had a RB500 for a year or so, and have to say for the money it was very good at what I used it for.

Screamy parts in vocals and loud electric guitar. I would imagine it would have been well suited to brass.

I used an adjustable impedance input (probably a cop out way of doing it in focusrite twintrack pro)
for 250Ohm iirc. to get some highs back (and with professional 'air' setting engaged)
and a pop screen of course.

just in my experience.
they are still less than £100 delivered to UK

EDIT:
actually, I also forgot... the output was seriously quiet. which is probably why it was only ever used on those loud sources.

 

[fum]

welcome to the world of ribbon mics 

As you can see, the variability from one mic to another (even within the same model from the same company) is why I adopted the model under which I currently make microphones.

The only way I could guarantee that every mic sounds the way I think it should was to take all assembly, wiring, and ribbon manufacture in house.  Unfortunately, that didn't come without additional cost.

Somewhere out there, there's an inexpensive ribbon that will sound OK with your name on it.

Best of luck with the quest!

Regards

ju

 

[Violinist]

welcome to the world of ribbon mics 

As you can see, the variability from one mic to another (even within the same model from the same company) is why I adopted the model under which I currently make microphones.

The only way I could guarantee that every mic sounds the way I think it should was to take all assembly, wiring, and ribbon manufacture in house.  Unfortunately, that didn't come without additional cost.

Somewhere out there, there's an inexpensive ribbon that will sound OK with your name on it.

Best of luck with the quest!

Regards

ju

Right  I'm reading a lot in your forum here and this was my impression I appreciated also the files with comparisons made. I heard different transformer ( a Lundhall and a Samar posted in a topic of Marik ) and I was surprised for the difference on the noise. (P.S. I liked the Piano execution  )

I really would like to listen to a violin execution/comparison between Condenser large diaphragm and Ribbon. Main my reason
Nevertheless I'm appreciating more and more the Ribbon's sound with all other instruments.

 

[fum]

And just for fun, I just got this in the mail from an artist in Belgium a day or two ago.  Certainly not violins, but it's a ribbon fest 

http://www.youtube.com/watch?v=556B4JbXKfg&feature=share

(And I agree, Marik does great things with ribbon mics, and can play the hell out of a piano! )
Regards

ju

 

[Violinist]

And just for fun, I just got this in the mail from an artist in Belgium a day or two ago.  Certainly not violins, but it's a ribbon fest 

http://www.youtube.com/watch?v=556B4JbXKfg&feature=share

(And I agree, Marik does great things with ribbon mics, and can play the hell out of a piano! )
Regards

ju

as far as I can recognize what is on it: it's a Shynibox Ribbon Mic  Do I wrong ?

 

[fum]

I believe it's a 46MXL on all, which is why it was sent to me 

 

[abbey road d enfer]

Excellent song! I love Soul sister, since their first hit "The way to your heart".
But the video is lip-synced, so the microphone we see in it may well not have been actually used for the takes...

 

[Marik]

I have also some technical doubt, related to the issue above: How can be generated a so strong "hiss" by a passive circuit that hasn't any other component than a transformer and a "quite common" motor?
Is that an issue that may be generated by the transformer itself?

Throughout the years I saw hundreds of different Chinese ribbon transformers. They are quite inconsistent. I saw ratios anywhere from some 1:30 up to 1:85 (in passive ribbons!), with short turns and screwed up inductances.

Say, we've got a 1:85 transformer. The typical Pri DCR 0.3 Ohm (which is quite a bit higher than even the ribbon itself), then the translated output impedance is already 2,167.5 Ohm (and this is before taking into account ribbon itself, imperfect clamps, and secondary winding DCR), which is about 11dB higher in noise than that of more common 200 Ohm source.

Another (significant) source of the noise is very thick ribbon, which has high mass. Up to a certain point there is a linear ratio between mass and output, so think 2um has 3 times higher sensitivity (i.e. some 9dB) than 6um. True, the 2um is 3 times thinner than 6um and has that much higher DCR, but since the stock transformer is the primary source of the high resistance, it really doesn't matter in this case.

Best, M

 

[manulaudic]

I would go ahead and get the T-bone. Change that tranformer for a Lundhal, and put a thinner Ribbon then.

I believe with the first easy mod(Transfomer) sound will be much more improved.

Oh and i did a session last week, we had two stock RB500 in room mics for drums, that into 1176. It's Amazing !

Good luck,
Manu

 

[zebra50]

I have an RB500 on the bench this week, and everything is way off spec.

The ribbon feels thick - about 5 or 6 micrometers thick, and measures 0.3 ohms. I can even bend it by hand without it tearing.

Inductance ratio on the transformer is around 1:100 and the output impedance measures at 3K ohms!

These are sold as having an output impedance of <200 ohms. How do they get away with this?

http://images.thomann.de/pics/prod/172090_manual.pdf

My impression is also that they use the thicker ribbon to make manufacturing easier / less skilled, and then wind the transformer to a super-high ratio to get the output level back up to a decent level.

 

[manulaudic]

Yes this is where you see that no control is being done on Thomann.

I've had great t-bones and also very bad ones.
I guess if one knows how to replace a ribbon (I don't, it's quite delicate) and output transformer for this one : http://www.lundahl.se/pdfs/datash/2912.pdf You end up with a good microphone. Damping the body can also be done. I've had friends filling the low part (metal part of body) with Paste to cut the resonance. Don't know if that is actually a myth or not.

Manu

 

[Kingston]

Damping the body can also be done. I've had friends filling the low part (metal part of body) with Paste to cut the resonance. Don't know if that is actually a myth or not.

The bodies do "ping" so yeah damping is a good idea. But not with any paste. Cut and fit a piece of kitchen/batchroom sponge or whatever plushy material you have at hand instead.

 

[Violinist]

Reading these feedbacks, I'm really concerned about Thomann and its t.bone stuff and I put in hold my purchasing.

Why? Because it's even illegal to sell something, declaring on it ceratin characteristics and it hasn't. I'm wondered about German Quality that's (was!) known to be strong.

I have note the necessary skill to change so tiny Aluminum foil.
The issue related the transformer doesn't worry me, but the Aluminum foil yes ... and much

 

[Marik]

I have an RB500 on the bench this week, and everything is way off spec.

The ribbon feels thick - about 5 or 6 micrometers thick, and measures 0.3 ohms.

That is strange. The thicker the ribbon, the lower resistance, so it should be under 0.1 Ohm. The only explanation I can find is dirty or contaminated clamps.

In any case, whether it is T.bone, or 205, (or for that matter most of the other Chinese mass produced microphones), consider it as a kit, which you will need to take apart, clean, and then put back using good parts.

Best, M

 

[zebra50]

The only explanation I can find is dirty or contaminated clamps.

Oh yes! I am quite sure of that.

 

[manulaudic]

Yes !

You are not getting german quality. This is straight from China, no control and that is why price to so cheap ! Though 95 euros is very cheap for a microphone. Couple of mods and you might end up with something very good !!

Then you go with something in between : Cascade Fathead http://www.youtube.com/watch?v=Pl-WCsP3pZk&feature=player_embedded

M

 

[Violinist]

REMOVED BY THE AUTHOR because not in the correct topic.
Sorry