Neumann / RFT MV 101 PSU / Preamp Question

[thor.zmt]

That isn´t a professional solution. You can do what you like.

I have seen two to-92 in an ALU shell in lot of japanese gear. Worked fine.

Ultimate point is, if one of the transistor arrays dies after 5 days (after all RFT stands for "Reicht Fünf Tage" - "lasts 5 days") it could be easily replaced.

Thor

 

[jokeramik]

Sehr lustig. Sehr.

Thor

weshalb?

 

[jokeramik]

I don't have this preamp. But I can read a schematic.

Thor

Du bist Klasse!)) You are a great guy!!)
Have a nice day!

 

[jokeramik]

I have seen two to-92 in an ALU shell in lot of japanese gear. Worked fine.

Ultimate point is, if one of the transistor arrays dies after 5 days (after all RFT stands for "Reicht Fünf Tage" - "lasts 5 days") it could be easily replaced.

Thor

You can do what you like!

All my preamps (V781, MV 810 and so on) work with all original transistors very fine. There are also very old germanium transistors. So your spell can't work..
Best regards!

 

[jokeramik]

The B340 used in the MV101 was made by RFT, East Germany.

Thor

Made in the German Democratic Republic -> GDR)

 

[abbey road d enfer]

Sehr lustig. Sehr.

Thor

weshalb?

Please gentlemen, rules! English only and no personal attacks, even when disguised as pleasantry.

 

[jokeramik]

Please gentlemen, rules! English only and no personal attacks, even when disguised as pleasantry.

Ok! Yes!
Best regards!

 

[thor.zmt]

Please gentlemen, rules! English only and no personal attacks, even when disguised as pleasantry.

Ok, english.

Given my experience with east german semiconductors (IN then East Germany) my reaction to claims that east german semiconductors reliably met specifications caused me to go: "Very Funny, very!"

Thor

 

[thor.zmt]

Made in the German Democratic Republic -> GDR)

RFT = "Reicht Fuenf Tage" ("Lasts Five Days").

Thor

 

[13engrsapper]

This is not an Neumann Preamp..)
This unit was developed and manufactured in Dresden by VEB Messelektronik "Otto Schön".
I think this unit is a measuring preamp. You have the original documents?
Is it possible to send me a scan of the hole documents you have?
Then I can help you.

Be carefully, because there are some transistor arrays inside (B340 and B341). The arrays are out of production and no compatible product is available.

Best regards!

RE: B340/341 etc. I think we have some RFZ compressors that use them too (the old East German ones matched transistor arrays). Knock on wood, they have never given us any trouble.

THAT corporation makes nice matched transistor arrays - or did I have not looked in a few years.

I am with everyone else with the build your own supply. Unless the supply is part of "the tone," which I have not found to be the case in solid state stuff.

Typically older solid-state power supply designs... well there is not much to love about them, lots to learn, but not much to love. Unless you need something to keep your coffee cup warm while you try to figure out where all the odd noises are coming from in you gear.

 

[jokeramik]

RE: B340/341 etc. I think we have some RFZ compressors that use them too (the old East German ones matched transistor arrays). Knock on wood, they have never given us any trouble.

THAT corporation makes nice matched transistor arrays - or did I have not looked in a few years.

I am with everyone else with the build your own supply. Unless the supply is part of "the tone," which I have not found to be the case in solid state stuff.

Typically older solid-state power supply designs... well there is not much to love about them, lots to learn, but not much to love. Unless you need something to keep your coffee cup warm while you try to figure out where all the odd noises are coming from in you gear.

Yes, the late version of the V713 -> I think V 713/h uses transistor-arrays in the control loop.
Yes, THAT Corp. manufacturing some arrays in the 300 series. That could be work.)
Best regards!
jokeramik

 

[Somkereki]

Dear Colleague ! I have been using an MV 102 measuring microphone with the accompanying sound pressure meter type 00 017 for about 40 years. It is fully compatible with B & K's similar device, except that the buttons are not as nice. Last year I decided to upgrade it, mainly because of the electrolytic capacitors. To my surprise, the high-value ones were all perfect (greater than 200 uF) The low-value ones were unfortunately dried out and had a high internal resistance. (I checked with an HP 4262A LRC meter, which was possible at a frequency of 10 KHz) I replaced them with high-quality foil capacitors. Fortunately, I did not have differential transistor pairs manufactured on a chip. The more delicate stages had Texas I transistors, the rest were DDR products. Well, I replaced the transistors with Toshiba 2SC2240 and 2SA970 low flicker noise types (after selection). The surprise: The base noise decreased from 4 uV to 0.1 uV.! Of course, this is so unusual because, according to the specification, the instrument measures from 2 Hz. (in fact, I measured 0.3 Hz (-3 dB) My other comment. 10nF capacitors connected in parallel with the diodes are necessary, they really reduce the switching noise of the diodes. I don't know what your mechanical construction options are, but I would rather buy the factory preamplifier. (There is a lot of work with it) I would definitely check the electrolytic capacitors and only replace them with good quality ones (low ESR). They can also cause noise! But I even came across a foil capacitor that had a high leakage current. I check it with a Radiometer IM6 type Megaohmmeter (up to 1000 TeraOhm and the test voltage can be adjusted from 1V to 999 Volts. I have a good lab, because I have been repairing studio condenser microphones for decades. I wish you the best of luck! It's worth it, if it's in order, it's no worse than other Western European or US instruments. If you have any questions, I'm happy to help . My "obsession" is reducing the noise of the devices and making them better. I also have a Neutrik A2-D Audio test & Service System instrument (the graphs on the screen I can also print.)

 

[berret]

Hi guys, just a question, not directly related to this subject, but...
Is there anybody who has a link to the schematic of the mv101 microphone itself? That would be very helpful. Thanks in advancd

 

[bremusound]

MV101 Schematic

 

[smilan]

I have one more question about the MV101, I would like to experiment with different capsules.
What is the type of connector for this mic?

 

[bremusound]

The thread size (metric) is M20 x 0.5