mic pre #7

[ioaudio]

[quote author="ioaudio"]sound sample of a fender precision bass via di...
no dynamics or eq added, pure signal.[/quote]

 

[rotation]

It doesn't matter if other people didn't hear preamp. I would like to hear what you think about it. As i said i find bass good sonding, but there is a bit of hiss. Maybe it's not from preamp..Did you ever record vocals with this? What do you think?
Thanks Miha

 

[ioaudio]

as i said before, i think its good on vocals, git, and bass. the hiss might be from the active pickups in that specific fender bass.
build it and listen to yourself :thumb:

 

[rotation]

Ok, thanks.

 

[rotation]

Hi Max or others!
After deciding to give a try to #7 i have several questions.
-Which OEP iron did you use? Can you tell the Farnell code?
-Do you know any good source where is point to point wiring easy explained including pictures? I've done the search over Prodigy, but can't find it.
-Is veroboard ok for point to point? It seems more like pcb..
-Have you got suggestions on choice of components? You use Tesla's EF86 and OEP input iron. What about capacitors?
-Would you share more samples, maybe vocals and guitars?
I hope i didn't ask you too much. Project seems interesting because of simplicity, low cost and good sound (ok, i only heard bass), that's why i will buy good components and try to do my best with soldering and metalwork. I hope the result will be warm sounding preamp with some character, not sterile daw preamp. Am i correct?

 

[ioaudio]

hey,

i´ve used the oep A262A3E 1+1:6.45+6.45 with the A262CAN.
i only know the rs-components code : 210-6425 and 210-6469 for the can.
there´s a section at www.rs-components.at for RS v Sloveniji.

i recently saw a new interesting input transformer:

X187B from oep - rs-components code 210-6352
impedance ratio 200: 50k ! did somebody use it already?


for point to point works: have a look how others do it and try yourself. honestly you cant really destroy something, and its very easy to fix if something is wrong. but dont forget the bleeder! always measure b+ on psu filter caps before touching anything after power up/down.
for really nice layout have a look for NYD´s work, as recently shown on the mila1
http://www.groupdiy.com/index.php?topic=16316
here´s a pic of how i did it... i like wood...
http://groupdiy.twin-x.com/albums/userpics/10055/layout.jpg
in this picture you can see a variation of different caps, like this old oil cap for the di input. for caps i can say: try different ones and listen. thats fun about point to point, you can instantely replace capacitors of different sizes and listen to it. for a starting point you cant go wrong with wima (mks4).
when a nice sample of one of my pre´s "happens" , i´ll likely post it here.

 

[rotation]

This was really fast. Thanks a lot, i got more or less all informations i needed. But it seems you don't really like to comment sound. Can you at least compare it with some known tube pres. I would really like to know what i'm doing. But, of cours, i will wait for samples. We listened bass with friend, and he is also amased by it's sound. We like it's detailed sound very much.
Thanks again, and have a good time.
p.s.: It seems you are familliar with slovenian language. Don't forget to contact me if you come !!!

 

[ioaudio]

[quote author="rotation"]But it seems you don't really like to comment sound. [/quote]
i just try to be careful...its already difficult enough to describe the sound of a micpre i didnt do myself...unlike others i dont want to do statements like super high end resolution whatever just because i build the unit.
i posted that particular bass sample because it reflects the sound of the amp in a good way - definately more colour than a mackie, but clean enough to do acoustic git with dynamics or even ribbons. for example i like recording vocals with it and a akg414, it adds something, whereas a 414 with a transformerless sandstate preamp sounds a bit boring sometimes...
but now i wasnt careful any more :? :grin:

 

[ioaudio]

update current production see first post.

 

[rotation]

Hi Max!
I'm coming back again :grin: with question. I would like to know if #7 has enough attenuation to pass line level signals. Did you ever try this beside mic and di?
Thanks Miha
p.s.:This was discussed already, but i would like to know if you tried it. Beside this i would like to try saturate first or second tube to see what it does to the sound. Is this possible without adding another stage? And is it better to add pot instate of resistors to pad the signal, a volume control?

 

[ioaudio]

hi miha :sam:

it depends very much on the input transformer and its ability to handle line level signals. you could
1. add a variable input pad before the input transformer like -20, -30 and -40 db.
2. add a (variable) pad to the DI and run it unbalanced.
3. add a switchable seperate line input which goes directly to the level pot and ommits the ef86 stage. also unbalanced operation.

good luck!

 

[rotation]

Thanks :thumb:
Yes, i have to get transformer first..Cash box is very nice idea for one channel preamp. I have two now. And effect that painting does to it is much nicer than with rack.
See you soon!
Miha

 

[rotation]

Hey Max!

Lets talk about #7 here. As i said a friend is using this preamp as a DI now. That's because we only tried it with suggested OEP and like it as a DI much better. But, i used old tubes, parts, layout was not very good (we had some noise when used as a mic pre).
Do you know how much gain it has in penthode and triode mode?
What are you using #7 for?
Have you got any records done with #7?
We heard bass, it is very nice, and i can confirm i had very good results with DI too. It was actually better than any other DIs we had at hand; Radial, Behringer and active transfomer based from me.
do you still have schematic for preamp and PSU? I don't find it anymore.

Miha

 

[ioaudio]

i updated the first post for schematics and pictures from the prototype.
here´s a instrumental sample from a recording i did lately, using the pre#7 on drum overhead, bass and guitars.

http://www.twin-x.com/groupdiy/albums/userpics/chute_sample.mp3

overheads are cmv 563 + m7, bass di, git´s sm57, all going direct into rme multiface, (roughly-)mixed itb

-max

 

[rotation]

Nice to hear this sample. I will hear it tomorow on my bigger system and comment it. And thanks for schematic :thumb:
Btw, was EF86 connected as a triode or penthode? There is penthode/triode switch..

Miha

 

[skipwave]

Very clever how you worked the 20db pad into the gain switch. I'm always bitching about needing lots of little toggle switches for each mic pre. That's a great solution.

Nice sample track!

I've got to make a sample recording with my 6EM7 pre. Used it last weekend on snare, with NYD One-Bottles on overheads. Very nice. There is something about the way that a simple, well-designed tube pre handles drums that is just sweet.

 

[ioaudio]

thanks!
miha, if i remember correctly i used triode for overheads, pentode for bass&gits.

 

[rotation]

Well, i managed to listen on my monitors. Guitars are very nice sounding. Which guitar and amp did you use? Snare and cymbals are fine too.
But i don't hear the bass well. It is hidden somewhere behind...
Yes, sweet guitars and drums.

Miha

 

[ioaudio]

two git players, one with gibson sg and carvin amp, the other i don´t remember... the mix is rough, maybe i´ll update leter.
-max