GroupDIY

Project Specific Discussions => Preamplifiers => Topic started by: [silent:arts] on November 25, 2012, 11:42:38 AM

Title: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 25, 2012, 11:42:38 AM
K13117 PreView (http://www.nrgrecording.de/nrg/viewtopic.php?t=2364&highlight=k13117)

K13117 Schematic (http://www.silentarts.de/DIY/K13117/K13117_rev02-Schematic.pdf)
K13117 PCB (http://www.silentarts.de/DIY/K13117/K13117_rev02-PCB.pdf)
K13117 BOM (http://www.silentarts.de/DIY/K13117/K13117_rev02-PartsList.pdf)

N13117 Schematic (http://www.silentarts.de/DIY/K13117/N13117_rev02-Schematic.pdf)
N13117 PCB (http://www.silentarts.de/DIY/K13117/N13117_rev02-PCB.pdf)
N13117 BOM (http://www.silentarts.de/DIY/K13117/N13117_rev02-PartsList.pdf)
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: kante1603 on November 25, 2012, 12:00:07 PM
Now why does that look familiar to me....... ;D

Udo.
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 25, 2012, 12:02:28 PM
You might visit a german Forum or Fratzenbuch? ;D
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 25, 2012, 12:14:08 PM
HOT!

(http://audio.kubarth.com/k13117/k13117_grill.jpg)
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: 3nity on November 25, 2012, 08:54:49 PM
Is this hot like really cool or hot like transistors really got hot?? lol
Tell us a bit more about it.
Thanks
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: okgb on November 26, 2012, 11:39:47 AM
 you Germans and your wacky K's ! Lean meat  ?  low fat ? pyramid power ?
I see xfmr goodness and allot of caps , hmmmm , curious drizzeled with fat ?
not copping pier's pre eh ?
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 26, 2012, 06:18:59 PM
Tell us a bit more about it.
Transformer balanced input and output (designed for the specific transformers, no options)
pure classA running on +/- 30V
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 26, 2012, 06:21:45 PM
not copping pier's pre eh ?
not copping anything  8)
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 26, 2012, 07:27:47 PM
not copping pier's pre eh ?
Greg, since I have been asked: what do you mean exactly?
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: okgb on November 26, 2012, 11:56:29 PM

 Since I didn't know , I was referring to Pier's ma-1 germanium pre , because I couldn't see & your's
didn't seem to be a 2520 type as his was not , was trying to figure it out , just a little friendly kidding .
class A Iron goodness ?
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: desol on November 27, 2012, 12:37:42 AM
To tell you guys the truth...i haven't been able to get that chicken out of my mind for that last two days.
Mmm...looks like garlic hot sauce maybe? Anyway...i just picked up a family pack of thighs.
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: grantlack on November 27, 2012, 12:48:20 AM
let me guess... the red wire is the NFB feed from the nuclear reactor's gas turbines?  ;D
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 29, 2012, 11:23:03 AM
Schematic (http://www.silentarts.de/DIY/K13117/K13117_Schematic-Preview.pdf) without component values.

We will limit this project to 60 / 30 PCBs (= 30 Stereo Sets)
PCBs will be ordered next week.

Darius made some listening tests, description in german only:
http://www.nrgrecording.de/nrg/viewtopic.php?t=2364&start=98
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: dmp on November 29, 2012, 01:09:40 PM
Rg1 / Rg2 control the gain? What is the max gain?
FYI for others: there are some nice pictures on page 5 of the German forum.
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on November 30, 2012, 01:13:23 PM
Rg1 / Rg2 control the gain? What is the max gain?
correct. the value table Darius calculated did either go from 20 to 64 dB, or 25 to 69 dB.
this was done for Pikatron a output transformers, we now decided to go for a Haufe which needs some adjustment. I'm sure Darius is already calculating  8)
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: dmp on November 30, 2012, 05:27:32 PM
I see two MAT02s in the pictures... cool. Makes me think this might be like a 990 with class A throughout.  :)
Have you compared the Haufe to a Jensen 16b?
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on December 01, 2012, 10:49:38 AM
Have you compared the Haufe to a Jensen 16b?

no. and to make support etc easier transformers are fixed (input = E-1420, output = RK494), no options.
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on December 18, 2012, 09:12:56 AM
Preliminary documents (values may change):

K13117 Schematic (http://www.silentarts.de/DIY/K13117/K13117_rev02-Schematic.pdf)
K13117 PCB (http://www.silentarts.de/DIY/K13117/K13117_rev02-PCB.pdf)


N13117 Schematic (http://www.silentarts.de/DIY/K13117/N13117_rev02-Schematic.pdf)
N13117 PCB (http://www.silentarts.de/DIY/K13117/N13117_rev02-PCB.pdf)

One unit is on the road for listening tests to finalize some component values  8)
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on February 03, 2013, 08:07:37 AM
some Pics of the first K13117 (copyright by Darius Kubarth)

(http://audio.kubarth.com/k13117/k13117_front_2.jpg)

(http://audio.kubarth.com/k13117/k13117_innen.png)

(http://audio.kubarth.com/k13117/vorverstaerkervergleich_2.jpg)

(http://audio.kubarth.com/k13117/vorverstaerkervergleich_6.jpg)
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: strangeandbouncy on February 03, 2013, 02:27:51 PM




 . . . I am not sure your gain knobs are big enough. . . .
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: braeden on February 03, 2013, 04:52:39 PM




 . . . I am not sure your gain knobs are big enough. . . .

Big knobs = big gain.

I actually have a set of these lying around somewhere, I think they're a little bit smaller but I want to get rid of them (hint hint, anyone interested?)
Title: Re: [Teaser / Feeler] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on February 04, 2013, 05:24:24 AM
I now take pre-orders for a one-off run K13117 PCBs (and transformers) (http://www.groupdiy.com/index.php?topic=39570.msg488632#msg488632)
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on March 12, 2013, 01:11:57 PM
Changed the title to [BUILD] and added documents in the first post 8)
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: 100WChris on March 21, 2013, 08:04:26 AM
Hi!
I did it!  :)
First test with the K13117. Everything is working, no smoke, only good sound and really deep low end!
Thanks to Volker and Kubi for this great project.
(http://www.chrisreiss.de/K13117-Testaufbau.jpg)
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on March 21, 2013, 01:36:25 PM
First test with the K13117. Everything is working, no smoke, only good sound and really deep low end!

 8) 8) 8)

now a nice enclosure, gain switch and you are done.
keep us updated!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on April 06, 2013, 06:37:16 AM
Hi Volker,

package arrived well, as i already mailed you.
Short question, is there a plan/way to add 48V phantom power?

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on April 06, 2013, 08:53:17 AM
Sure. Your PSU already has the 48V.

Connect it to a switch, and to 6K8 resistore to the XLR Input and you are done.
A Cap to ground might be another good idea to have some "slow start".

Or use MIO PCBs (http://www.silentarts.de/Techtalk-Laden/MIO_rev01-Doku.pdf),
the added PAD and polarity reverse won't hurt in a Mic Pre.
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on April 08, 2013, 05:19:10 PM
Hi volker!

Cool, i missed that (just don't have the psu pcb handy to me).

An other short one, is there a recommendation / source for the gain switch / pot?
At NRG I read something about an 2x24 ELMA switch!?

Currently gathering things together.

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: 100WChris on April 12, 2013, 01:01:06 PM
Hi!
The K13117-Switch is a 2 deck, 2 pole, 24 step switch. The only one i have found is the Elma Switch 04-2133 (https://www.distrelec.de/ishopWebFront/search/luceneSearch.do?dispatch=find&keywordPhrase=211283)
if you don´t need 24 [email protected] i guess you can use a 12 step switch, but again it has to be 2 decks and 2 poles.
if you find a cheaper solution let me know :-)
Chris
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on April 12, 2013, 05:47:11 PM
Thanks a lot Chris for the link!
But hell... this one is expensive!!  :o  :o  :o Shocking!!!
There must be another way....!?

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on April 13, 2013, 04:30:20 AM
yes, Elma Series 4 is a very good switch (but expensive).

others will work too, if you want 35 steps  8)
http://www.ebay.de/itm/PP36-21-Russian-military-Rotary-switch-35-steps-2-plates-2pcs-/251195107080?pt=LH_DefaultDomain_0&hash=item3a7c652708#ht_904wt_964
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on April 13, 2013, 04:33:16 AM
haven't used one, but looks fine:
http://www.ebay.de/itm/1-2pole-23step-ROTARY-SWITCH-Attenuator-Pot-Potentiometer-Volume-Control-DIY-/320953851027?pt=Vintage_Electronics_R2&hash=item4aba571c93#ht_2116wt_964
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on April 17, 2013, 04:52:45 PM
Hi Volker,

thanks for the links! I guess i have to improve my ebay search skills  :D

The Russian switch looks great and would fit perfect the subline of the project "Big knobs, big gain!"  ;D
But I will go for a one unit case...

I've ordered 2 of the switches of your second link, we will see...

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on April 21, 2013, 09:20:29 AM
Hi Volker,

I'm missing the power transformer on the BOM, any recommendations on that?

And I'm just looking at the Gain-Resistor-sheet.
If i'm taking 1db steps up to 23 positions, it leads to  gain range of +20 to +44db.
In this case Rb is constant 47k, so a simple 1 row 23 step could do the job, couldn't it?


ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on April 22, 2013, 12:02:26 PM
I use this one - might be a little bit oversized:
https://www.distrelec.de/ringkern-transformator-80-va-25-vac/noratel/ti-044218-me-ec/353317

Don't have the gain resistor sheet upfront right now,
but yes, sounds legit (if you install the 47k resistor fixed)
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: 100WChris on April 22, 2013, 12:37:45 PM
Hi Dr_J!
I used a 2x30V/80VA trafo to power my test-build. Also oversized i guess, but i had i laying around...
Kubarth pointed out in the german forum, that he used this switch for his build:
http://uraltone.com/kauppa/product_info.php?info=p1077_Rotary-switch--2x24.html&XTCsid=jb7dm7trbdnbhjgj3umi7dihq6
it´s cheap, so no need to lose 30dB of gain just because of the switch... i´ll order two of these
best regards
Chris

Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on April 22, 2013, 05:57:43 PM
Hi Volker,

thanks for the link and the included  technical data of the power transformer (backwards calculations are a bit sketchy).

@110WChris:
I have read it and if i compare the pictures following the link that Volker posted above... to me they both look similar...
Whatever, i ordered 2 of the Chinese ones according to the Link of Volker, we will see...
Maybe we could make a comparison here...

The Gain resistor value of [Rb] could be fixed @47k in case of +1db steps up to +44db gain, it was just a question
of understanding and maybe interesting for some other builders...

Next is to figure out the front panel design, that I would like to have... knobs, switches, lights... some fun here  ;D

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on April 24, 2013, 01:48:41 PM
Hi,

i'm currently thinking about adding a JLM GoBetween, any thoughts on that?
Especially for the PAD switch? Is a PAD switch worse thinking about here?

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on May 13, 2013, 05:33:02 PM
Hi every one,

I have ordered the Chinese 24pos switch, they've arrived some days ago and look real fine!!!
This was a great hint!!
To me, i'm happy not ordered the Elma ones.... (mybe in a 100 years i'll regret it :) )

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: 100WChris on May 14, 2013, 05:32:15 AM
Hi Dr_J!
i ordered mine in Suomi :) they look like this:
(http://www.chrisreiss.de/Switch1.jpg)
(http://www.chrisreiss.de/Switch2.jpg)
How is it going with your build?
Chris
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on December 18, 2013, 04:38:19 PM
Hi every one,

still working from time to time on this build.

I just mailed with Volker about wiring the Gain switch.
On the PCB are 2 connections labeled RG1 and RG2, these are
Ra and Rb in the Gain PDF "Widerstandstabelle für die Wahl der Verstärkung".

In a nutshell:
RG1 = Ra
RG2 = Rb


Wiring the 2 pol Gain switch, e.g.:

20db Gain -> Ra = 31623Ohm, Rb = 47000Ohm (Calculated Values, page 1)
Ra = 31623Ohm ~  33kOhm parallel with 820kOhm
=> 1/(1/33kOhm + 1/820kOhm) = 31723Ohm (Resistor Error ~0.3%) (Page 2)

So, Ra has to be made out of 2 Resistors in parallel at the first row of the switch!?
([email protected] Row #1: 33k || 820k, Row#2: 47k)

A'm I right Volker?


ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on December 19, 2013, 03:44:12 AM
Yes, if you want to limit yourself to E12.
I would just take one 31K6 resistor out of E48  ;)
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on December 19, 2013, 05:24:54 AM
Aaaaaaaaaaaaaaaaa...............    >:( >:(

It was too late at night...
Thanks for the hint!

Now I have a pile of unused resistors laying around...  :D
...and have to order some resistors...


ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on December 29, 2013, 04:02:32 PM
... fired it up right now the first time... no smoke  :D
.. voltages are fine... and we've a nice "Tonfrequenz Verstaerkung" on both channels...  ;D  GREAT!!
... and dead quiet!

Where's my beer.... and my DIY booze...  ;D

ROCK-ON!


P.S.: Pix coming soon...
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: 100WChris on December 30, 2013, 05:50:02 AM
Cool, another one joined the small club!
The K13117 became instantly my favorite pre for bassguitars! Thinking about building some Harrison Ford Filters: i need some low-cut-filters now  :D

Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on December 31, 2013, 02:18:03 PM
Hi Chris,

funny, when i play a bit around with the unit i although plugged a bass in my new BoHansen DI and into it... :)

Well how small is the club?!  ;) 

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on December 31, 2013, 02:20:51 PM
Hi,

when switch through (up and down) the gain steps from time to time the unit is dead for a minute or so. Sometimes switching phase helps...
Any ideas?

I'll have to do some more testing...

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on January 16, 2014, 04:07:54 PM
Here we go...  ;D

Front panel, as nearly always, from Frank (NRG).

ROCK-ON!
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: Dr_J on January 16, 2014, 04:11:34 PM
... and the guts...

I've used only white leds, they're very bright shining... maybe I'll play around with some higher resistors to lower current.
We'll see...  ;)

I had to lay down all capacitors to fit it all in 1HE case.
And of course i found out nearly after finishing soldering... grrrr...  :)

I although had to cut the heat-sinks to fit, temperature seems to be still ok. 

ROCK-ON!

Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: [silent:arts] on January 16, 2014, 05:08:19 PM
Creative and nice  :) :) :)
Title: Re: [BUILD] K13117 (ClassA MicPre by Darius Kubarth / Kubi)
Post by: funkymonksf on January 22, 2015, 04:35:43 PM
I'm very interested in building a stereo pair of these pre-amps. Has anyone utilized a potentiometer instead of a 2x24 switch? I'm curious what value and type (log or linear) I should use. I really am insecure about doing my own switches, so any advice on what values i should use helps to. I've spent two hours looking for advice on stepped switch wiring with little luck, the only source I found was for stereo attenuators for volume control.. Is it the same idea for gain control in a mic pre?