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R/E/P => R/E/P Archives => Oliver Archut => Topic started by: SingSing on January 25, 2005, 02:20:25 AM

Title: The different V76 models
Post by: SingSing on January 25, 2005, 02:20:25 AM
Hi Oliver,
I have a couple of standard V76 and V76m and I know there's also the V76s. On the net I've found some brief explanations to my question, but could you describe the difference between these modules both technically and soundwise? Is there any particular model that is considered better than the others?

Thanks
Stefan
Title: Re: The different V76 models
Post by: Oliver Archut on January 27, 2005, 08:37:49 PM
Beggining of 1954 the IRT and Maihak made several units(about 50 or so),  that were just labeled V76, but had all the 80 low and 3kHz high cut.

The historic TAB company started in 1956 with the production of the V76 version as mentioned above, adding the V76 with 120Hz cut in 1960, since than there is the 80 or 120 extension on the designation number.
The 80 unit was aimed for the radio market, the 120 for TV studios.
Both units are the same with the difference in the filter choke that set the cut off frequency.

Also in 1960 the "S" version was introduced, "S" stand original for "Schallplatte" or for Vinyl Disk, indicating "Studio use" and in 1965 official changed to "Studio".
The "S" version is quite different, multiple switchable low cut, and also multiple switchable high cut. Filter inductor are made from NI/FE alloy for better sound performance than the standard ferrite cores in the 80/120 units.
The input x-former, even barring the same part number, it is similar to the standard version, but hooked up in a different way, also a bit differently wound. There are also a few minor changes in layout, wiring, etc.

The "M" version was released as a reference amplifier or better measuring amp indicated by the "M" the german word is "Messverstaerker". Technical speaking and entire different amplifier, output and tubes are the same, input and front amp are different as can be. Input x-former is 10kOhm impedance, and max. gain is 60 dB. About 600 units were made.

In 1968 the "MT" was released the "M" version as technology/laboratory amp, with a frequency response 5 to 50k Hz. a bit different than the M version in circuit tree, and 66dB of gain. Less than 100 were made...

Nearly at the end the "FR" version was designed for better console layout only used in 24 plus channel consoles with remote controllable gain. The standard 80/120 chassis without the filters...

There are a few custom version made over the years, and it is worth mention that there is an EMI made V76S with a few different options, x-former are the same than the TAB made "S" version...

Hope that helps....
Title: Re: The different V76 models
Post by: SingSing on January 31, 2005, 07:41:29 AM
Hi Oliver,
thanks for your answer. Well, though I'm no techie I seem to grasp some of it.

Could you clarify a bit regarding the V76m? Is it different from the original V76 and V76s in ways that makes it unsuitable as a mic pre?`

Thanks again,
Stefan
Title: Re: The different V76 models
Post by: Oliver Archut on February 01, 2005, 12:19:40 AM
Hello Stefan,

the V76M is not a mic pre, even if it can be used as one. The high input impedance (10k Ohm) can be very unstable if used as a mic pre, but also can shine and boost the mic to the next level.
The front end circuit is quite different as well as some other minor differences..
It is no all around mic pre than the V76S but if you have money, it is good to have in your arsenal...
Best way to describe it, can make a SM57 sound like a million dollar as well as a U47 feel like a cheap tramp....

Hope that I put it into proper terms...

Best

Oliver
Title: Re: The different V76 models
Post by: wwittman on December 17, 2006, 04:40:46 PM
Oliver Archut wrote on Tue, 01 February 2005 00:19

...
Best way to describe it, can make a SM57 sound like a million dollar...



so it's a miracle worker?
Title: Re: The different V76 models
Post by: Oliver Archut on December 19, 2006, 10:06:56 PM
No it is not a miracle worker, it just get everything there is to get out of the mic that is hooked up.

The SM57 is a pretty good sounding mic, only problem is the transformer, either you get yourself a mic pre with a pretty good resolution or you mod the SM57 with a new x-former.

As I said before it can also happen that a 47 will not sound good at all.

Best regards,

Title: Re: The different V76 models
Post by: Andy Simpson on February 06, 2007, 06:54:47 AM
Oliver, I would be very grateful if you could you elaborate on the transformer upgrade for the sm57? Have you done it?, What part did you use? and what were the results?

Thanks in advance.

Best regards,

Title: Re: The different V76 models
Post by: iCombs on February 06, 2007, 12:15:35 PM
It'd probably sound like an SM-5 or SM-7.  I know that the SM-5 is based around the same Unidyne III capsule as the SM57.  If you poke around, you'll be able to find directions for pulling the transformer from a 57.

I would also be interested to know what transformers you'd reccomend, Oliver.
Title: Re: The different V76 models
Post by: Oliver Archut on February 08, 2007, 05:18:05 PM
Hello Andy,

I did a couple of sample x-formers a few years back, the stock x-former is a joke...
Biggest problem a good update x-former cost more than the mic itself so there is no market for selling it....
The sample that my test subjects like most was wound foilstyle,
no phase shift low strayfield...

Best regards,

Title: Re: The different V76 models
Post by: iCombs on February 13, 2007, 11:32:10 AM
could you suggest an existing transformer that would work well (or at least better) in an SM-57?
Title: Re: The different V76 models
Post by: MI on February 13, 2007, 01:53:22 PM
Ian,

I recall a thread in PSW about removing the tranny all together in a SM57 but can't find it now...

Aparantly this works well for loud instruments where you won't need to use as much gain.

The same thread mentioned using Jensen tranny but in an outboard box.

If you bypass the tranny make sure you wire the + and - properly otherwise it'll be out of phase.

Mario
Title: Re: The different V76 models
Post by: Oliver Archut on February 14, 2007, 12:52:15 AM
The SM57 is quite difficult to match to a transformer and to my knowledge there is no after market x-former currently available that will compliment the capsule of the mic.
Due to the low impedance a step-up transformer is needed, just taking a similar ratio will just pass sound, does it sounds good or improves the stock version? That is hard to say.
Placing a larger core x-former in a box, is not an solution at all, and direct no x-former is in my opinion questionable.

A direct coupled x-former with an electronic circuit that is phantom powered might be a solution...

Best regards,