F110 at The Factory

[thenovice]

how many around here have built this pre?
focusrite 110 based?

i was just wondering if i could get a bit more in-sight on building this pre?

yes,i did a search too,but haven't came upon
a mass amount of information,like for instance the n72 has ....

thanks for any pointers

c-ya

 

[Kev]

sorry
I haven't made this particular variant of it,
there are just too many good cheap simple Mic-pres to DIY

added to that THAT Corp has finally got the 1510 alive ... still waiting for some samples

Generally speaking though
A trafo to op-amp mic-pre can be an excellent work horse and probably as goos as the Green in its own way.
Has the advantages of the trafo up front and I think a unit like the OEP is a good choice.

My early PCB layouts for Project 2 and a simple PCB with an op-amp as a DOA drop in will give you the basic idea on how it might sound.
Then if you like the sound of that, a specific PCB to suit you needs can be made.
The same goes for Joes 99x PCB or Fabio's PCB

 

[thenovice]

[quote author="Kev"]sorry
I haven't made this particular variant of it,
there are just too many good cheap simple Mic-pres to DIY

added to that THAT Corp has finally got the 1510 alive ... still waiting for some samples
[/quote]

1510?

so in a nut shell your saying it's simply simplier to go with a variant to achieve the same sound [sonic quality?] / results?

the reason of me posting for this particular board,is the ISA is highly acclaimed in my genre of music ...

i stumbled upon that link for the factorys f110 but from my reading It seems like it may not be 100% accurate
so if I acquired all the parts,and assembled it,and it didn't work there may be errors other than mine.

so thats why I asked.

do you think the potential cost and time of trying to DIY the 110 out-weigh the worth.....

maybe a better idea to DIY a rivaling unit?

 

[thenovice]

btw do you know why the projects link at the factory doesn't work?
anyone?

 

[thenovice]

http://www.thatcorp.com/1510desc.html

you were refering to this right?
thnx kev

 

[Kev]

Yes the THAT1510
a drop in for the Analog Devices SSM2019 and SSM2017 (discontinued)
and the Texas Instruments INA217 and INA163

btw do you know why the projects link at the factory doesn't work?

yep
I'm in no hurry
there is a link into the projects page but you have to know it ... sorry
I had planned to open the door last week at the one year mark
but I just couldn't be bothered
I'm on night shift with the Cricket from England ...

... It seems like it may not be 100% accurate
so if I acquired all the parts,and assembled it,and it didn't work there may be errors other than mine.

could be
I did make Pete C's version and things were fine
Check Plot
http://www.diyfactory.com/projects/diy110/PC_F110_V4_CP.pdf
Over-Lay
http://www.diyfactory.com/projects/diy110/PC_F110_V4_OL.pdf
Bottom Layer
http://www.diyfactory.com/projects/diy110/PC_F110_V4_BL.pdf

Kev's F110 schematic
http://www.diyfactory.com/projects/diy110/F110_schem2.PDF

but as I said
there were other projects that were/are more deserving of time ... one day I may get back to it and present it better
The 5534 / 5532 chips may vanish soon ... so I just don't have it high on the list.

I was going to make a PCB that used the LM833 just to show a simple reliable Mic-pre coulf be made with a couple of op-amps and a trafo
.... see Joe's drawings of the Neve IC pre


The potential cost and time of trying to DIY the 110 or any of the simple units is very small ... you don't have to box it up straight away.
If you like the results then look to making a dual and putting it all in a rack box.

 

[dukasound]

Hi
Before anything to write thanks to Kev who help me for informations.
Here is F110 style preamp but without original output section with transistors and transformer.
www.dukasound.cg.yu/Data/Duka110.GIF
I used trim section like on original and output with NE5532 like on some balanced circuit.
Also Kev made similar circuit. If anyone have some sugestion about this kind of circuit let me know and what resistors are OK from Ne5532 3 and 5 pin. I find on some circuit both 470ohm. On Kev's drawing from 2002 I saw 470K and 10K. On GSSL I think both are 470ohm.
I will use LL1538 connected to 1:5 ratio. Also OEP can be connected.
Just to know: can anyone explain about making positive and negative out and why is in output stage signal connected to negative input of opamp (pin 2 and 6 pin)
Thanks in advance for help.
Duka

 

[Kev]

Duka,
I think you wioll find that the Gssl is 10 K and 10 K on the last op-amp
and 15k over 470 on the second last
as per your drawing and mine above.


These tow op-amps form the balance output driver.
working backwards
the very last one is in a unity config
10K over 10k

the second last one drives into it via the inverting input ... and so is inverted by comparison to the incoming

The second last op-amp CAN be set up as unity if you like BUT can also be set up for some gain as required.
15k over 470k

The fact that this op-amp is also in the neg input probably doesn't matter that much.

The use of the neg or pos input can be discussed latter and I'm sure PRR could keep us busy for a while with the various pros and cons.

The main point here is that both the op-amps output a signal reversed to each other
and so gives a + and -
hot and cold ...
pin 2 and pin 3
get it
:thumb:

Right at the end of the circuit is the 47k simple load resistors ... for when nothing is conected
and
the 100 R ... over current protection
and the Capactor ... AC coupled ... DC bloker
Both the resistor and capacitor give a Short Circuit Protection

I've over simplified things as usual

Check out the Rane site for their way of doing a similar thing
http://www.rane.com/pdf/mlm42sch.pdf
look at their output
I hope this is the right sort of Mic-pre cos I can't load this one tonight as I'm in Slooooowwww net world.

 

[dukasound]

Hi Kev
Thanks for reply
I saw on GSSL schematic 15k and 470 (from both + of 5532) but on board are (I think, maybe wrong) 470ohm.
Is it mean That I can use on last 5532 470K and 10K like on your schematic.
Your opinion about trim stage????
Duka

 

[DrFrankencopter]

In the GSSL, the stage right after the VCA is unity gain. The 470 Ohm resistor is on the non-inverting input, and serves only for biasing. The gain in this opamp configuration (which is inverting BTW), is determined by -Rin/Rf. Here, Rin is the 15k resistor feeding the VCA, and Rf is the feedback resistor (aslo 15k) hence we have a unity gain inverting stage.

Cheers,

Kris

 

[omeiko]

When I started my version of the f110 it was similar to Peter C's version.
Then later I added the original tx-balanced output section.
I don't want to spoil the fun but most of the sound of the unit comes from the toroidal output tx-section.
The front end is just clean gain with not much colour and the niceness comes from the toroidal tx.

I tried a lundahl ll5402 there also which was interesting too but ended up using the original tx.

I don't have the original unit to compare though so I can't comment on that.

Okko

 

[Flatpicker]

[quote author="omeiko"]...most of the sound of the unit comes from the toroidal output tx-section...[/quote]Is there a source for these?

 

[CJ]

If there is, send it to me for "evaulation".
Is this the green pumpkin or whatever it is?

 

[Kev]

[quote author="DrFrankencopter"]In the GSSL, the stage right after the VCA is unity gain.
....is determined by -Rin/Rf. Here, Rin is the 15k resistor feeding the VCA, and Rf is the feedback resistor (aslo 15k) hence we have a unity gain inverting stage.[/quote]

thanks Kris

here is the circuit Kris refers to
http://gyraf.dk/gy_pd/ssl/ssl_sch.gif
I should have looked at the circuit

see the * on that 15k into the VCA
see bottom of schematic
use 27 k for unity when running unbalanced

 

[Flatpicker]

[quote author="omeiko"]...I tried a lundahl ll5402 there also which was interesting too...[/quote]Interesting in what way? Did you configure it using the mixed feedback method shown on the data sheet - details?
(These are only $52 at K&K)

 

[thenovice]

[quote author="omeiko"]When I started my version of the f110 it was similar to Peter C's version.
Then later I added the original tx-balanced output section.
I don't want to spoil the fun but most of the sound of the unit comes from the toroidal output tx-section.
The front end is just clean gain with not much colour and the niceness comes from the toroidal tx.

I tried a lundahl ll5402 there also which was interesting too but ended up using the original tx.

I don't have the original unit to compare though so I can't comment on that.

Okko[/quote]

so it's all about the output then?
any more info?

btw if there is a link available can anybody post it for more info on peter c's version?

thnx

 

[strangeandbouncy]

Can anyone tell me if the output tx is the same "donut" type that is in an ic Neve desk? If so, I believe that Funky Junk has a squillion of them . . . .

 

[omeiko]

The out tx is an orange 'pumpkin' type toroidal with tertiary winding.
It can be ordered directly from carnhill and its model number is vt30408.

Interesting in what way? Did you configure it using the mixed feedback method shown on the data sheet - details?

I don't remember how I wired it but I suspect I didn't use this mixed feedback thing. It sounded nice. Clean and airy but still had some tx 'weight' in the sound. The pumpkin had more personality though.

 

[Flatpicker]

Great info - thanks! :thumb:

 

[jensenmann]

Is there the original outputsection schemo with this torroidtranny somewhere around? Or follows the tranny simply after the input OP?
cheers
Jens