• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Audio Note M7 Line Preamp??

Just found this.....different versions of M7??



ANM7.gif
 
I have built this line stage and I'm sure many others here have followed suit. I built the 5687 version except I added gas regulators to the circuit. Its a good sounding circuit. Shortly after building it I built a 12B4 line stage that totally blew away the 5687. There are several versions of the 5687 line stage and both produce about the same result.
 
Konnichiwa,

bee696 said:
Heard that Audio Note M7 Line Preamp is using single 5687 for line stage + 6X4 tube rectifier....REAL?? :confused:

Yes, really.

You need to realise that Kondo has had several Models under the general "M7" designation.

The "Full preamp" always used a 6072A Linestage with a Voltage Amp/Cathode follower combo and a variety of Phonostages, first 6072A Cascode into passive RIAA into 6072A and now ECC83/12AX7 with NFB EQ.

The Line Preamp originally used a single 5687 common cathode with the Output directly from the Anode, the current Linestage model is different from that.

For fun, the first Kondo "M7" actually used Mosfets, very special ones, not many where ever made...

bee696 said:
But in this website (http://www.audionote.com.sg/products/preamp/kondo/m7.htm), it stated that it's using 12AX7WA x 2 (EQ) + 6072WA x 2 (LINE) + 6X4 ?? :confused:

This website refers to the current M7 MKII KSL and the full function model.

Sayonara
 
  • Like
Reactions: 1 user
I have made this circuit, sounds very fantastic. I think it is clone of
original circuit.

http://img401.imageshack.us/my.php?image=anm78od.jpg

Thanks

JPS

JPS,

This board is available from kitparts. Everything they have is supposed to be a clone of an original circuit. Nothing could be further from the truth. I have two examples of their work sitting on my bench in the garage. While workable as a line stage not even close to the original. In my opinion not worth the money.
Mine are supposed to be Jadis and like I said not even close.
 
Konnichiwa,

JPS said:
I have made this circuit, sounds very fantastic. I think it is clone of original circuit.

An externally hosted image should be here but it was not working when we last tested it.



Surprisingly this circuit is practically exactly that of the linestage of the full function Kondo M7, including the paralelling of unequal value cathode resistors, except for the most important part, the valve. This should be a 6072A, NOT 12AU7.

Also, Kondo builds the circuit hardwired, on copper chassis and using his own Silverfoil & Mylar capacitors plus tantalum resistors....

Sayonara
 
Hi burndfingers

I had made the PCB myself. My preamp sound is excellent.
Thou I have not listened to many world famous preamps but
a friend of mine who has listened to lot of preamps said this one is top class. Simple and best.

regards

JPS
 
Konnichiwa,

rick57 said:
for the M7 to sound really good, does it need big $ components (in the way that much of the charm of the Ongaku probably derives from its exotic components)?

You do need a reasonable level of component quality, but surprisingly, most of the components Kondo used are fairly unexceptional, except for Tantalum resistor throughout and his own handmade silver capacitors.

I would suggest that using standard Metal Film resistors (2W) and Tinfoil & Polypropylene coupling capacitors will go a long way.

AN UK has now got Silverfoil & Mylar coupling capacitors but the prices are somewhat high....

Sayonara
 
Thanks KYW :)

Assuming you can adequately compensate for the big differences in gain (I have three systems in different stages of development), your thoughts on how it might sound compared to

A finely tuned hybrid:
www.aksaonline.com/products/products_GK1.html

A device switchable from rose coloured glasses to passive, etc:
www.mapletreeaudio.com/magic5.htm

very clean and borrowed from the past, er like much blues music:
The Heretical Unity gain line stage

A supposedly “blistering fast” ring-in
www.transcendentsound.com/preamp kit.htm

Thanks again

Cheers
 
Konnichiwa,

your thoughts on how it might sound

The M7line sounds nice enough, very much "Kondo" but slightly on the warm side.

I cannot at all compare to the others, I have not heard them.

I personally prefer passive linestages nowadays, but the M7line sounds very nice for such a simple design.

Sayonara
 
to esimate laquer

Thanks KYW, that is helpful

On another note, after reading your favourable posts on the subject, I emailed Dieter Ennemoser re C37 and have yet got no response, your thoughts:

“I have several paper cone drivers of different sizes (6.5 - 15").

I understand that it does vary, but as a starting point, on average - how many ml of C37 does it take for a good result on eg a 6.5” paper cone mid?”

Cheers
 
Regarding the cloned Kondo M7 preamplifier, can l straight swap
a12AU7 for a 6072A valve, the original used a 6072A, this answer
was a reply given by a member Kuei Yang Wang back in 2002 to a
member of the forum but he didnt say whether you could
without adjusting the ciriciut
can anybody help.regards LenB
 
LENB said:
Regarding the cloned Kondo M7 preamplifier, can l straight swap
a12AU7 for a 6072A valve, the original used a 6072A, this answer
was a reply given by a member Kuei Yang Wang back in 2002 to a
member of the forum but he didnt say whether you could
without adjusting the ciriciut
can anybody help.regards LenB


a more suitable plug and play tube to replace the 6072 would be 12at7(ecc81), without having the need to change any parts of the circuit.
 
I built the 6072 version a number of years ago - it was my first tube preamp. I used tant resistors and AN caps (not silver). I built it with the same choke loaded supply that was in the AN schematic, tube rectified, etc. You know, it was okay, but I don't remember it as a giant killer. Overall I find I like an anode follower better. Simple and direct. Of course, highish output impedance.