Posted on Saturday, 4th October 2008 by Auw Jimmy

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Well, I have one week holiday and I’m almost dead because of doing nothing. Since I have a pair of Aikido 9-pin Preamp PCB, why don’t I build one?

The main concern of this project is simplicity and cheap price. I don’t want to spend too much money for this project (just to kill my boring days).

So here is the PCB. Nice, sweet, well build by John Broskie.

The first thing that I do (after finding the component from my shelves) is to clean up the connectors of each component. By using a scissors, I clean up the component leads.

As you can see, the green box is a clean connector, while the red box is not yet cleaned part. By the way, I use cheap NOS Vishay L6C Metal Film resistor. Although it’s looked awful physically, but the value is still good.

I also test one by one. With my Ohm Meter, 1 MOhm resistor measured at 1016 KOhm. Hmm, 1.6% drift value seemed ok.

Then I start to put the components on the PCB and start the soldering process. I start with the smallest and shortest components first.

My tools, WBT Silver Solder and Goot soldering iron.

I also need to replace R15 with a jumper (because I configure this Aikido as White Cathode Follower). I use the lead from some component that I’ve finished soldering. I also wrap the jumper lead with WBT silver solder to prevent any corrosion in the future.

I also use old stock Vishay S139 resistor as output shunt resistor (just because I only have this resistor with 10-11 KOhm value). This is a damn good resistor at 0.01% tolerance. As you can see, the 11 KOhm value is 11 KOhm measured with my Ohm Meter.

For some mistake in soldering, I will use my Goot Solderwick to remove the wrong component. This is a clean and perfect way of desoldering process.

Well, two PCB are done! You can see some affordable components like Elna Cerafine, WIMA, Russian K72 Teflon and K40Y PIO, and Obbligato capacitors.

Another shoot from the top side. Beautiful color combination, isn’t it?

Some combination of resistor, from the Vishay S139, Kiwame, Vishay L6C, and Dale. The two K40Y capacitors are used for grounding the tube screen pin.

I have added the power supply board and also the attenuator board.

The power supply is a simple one, choke loaded (15H), two Samhwa 220uF/500VDC capacitors, and a tube rectifier with Russian 5U4C.

Another side of the power supply board. I use 1.5mm power supply cable. Thick, eh?

Since this Preamp will also act as my headphone amplifier, then I need to have a big coupling capacitor to drive my 32 Ohm Grado. I use Mundorf M-Lytic 560uF/400VDC. This should be enough to give high pass filter at 8.88 Hz at 32 Ohm load. The attenuator is ALPS 100K motorized potentiometer.

I ask my friend to build custom power transformer.

  • The primary is 0-220V
  • The secondary is 300V-CT-300V (100mA), 3.25V-CT-3.25V (3A), and 0-5.25V (3A)

Well, the Preamp is singing now. I use 6N1P and 6N6P tubes and 5U4C as rectifier.

The “giant” 6N6P. The combination of 6N1P in gain stage and 6N6P in buffer stage produces a perfect combination here.

I hear a B+ hum when testing. Then, I decide to add a neon ballast acting like a choke. So the power supply configuration is “Transformer-ChokeLoaded-Capacitor-NeonBallast-Capacitor”. This is a “poor” solution if you don’t have any extra choke and quite effective! No more hum, baby! You also can see a high voltage switch and how big the transformer is!

Add: I replace the Neon Ballast later with a choke (and produce even lower hum on my testing).

One shoot of the Aikido with 5U4C rectifier. Good performance rectifier with its price range.

A final shoot of my Aikido Preamp. I replace the 5U4C tube with 5U3C/5U4GB Sylvania Black Plate rectifier. It sounds even better in resolution and clarity. Overall, I’m quite satisfied with this as my holiday project. Will try to find a good chassis and mount it inside.




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Posted in DIY Audio, Personal | Comments (38)

38 Responses to “My Aikido Preamp with Standard Components”

  1. Andrie Surya Says:
    October 6th, 2008 at 13:13

    Gue yakin pasti manteb suaranya cuman, se affordable apa nih pak Jimmy?



  2. Jimmy Auw Says:
    October 6th, 2008 at 16:55

    Untuk kelas preamp 4 tabung, plus tube rectifier, rasanya sangat-sangat affordable Boss :)
    Thanks.



  3. Anand Says:
    October 8th, 2008 at 21:19

    Jimmy,

    Great blog site! What are you bias points for the 6N6P? I have been told that running them at currents of 18-25mA is best, or around 22 mA. Low plate voltages of 100-110V and then it really sings.

    I’m planning on trying 5965 as the 1st tube and 6N6P as the second. Thanks again for any help.



  4. Jimmy Auw Says:
    October 8th, 2008 at 23:39

    Well, I use White CF output stage, with 330 Ohm Cathode resistor at bottom tube.
    Plate voltage is around 255 VDC, Choke Loaded and CLC filter (310 VAC).

    Thanks.



  5. Paul Yahya Says:
    October 9th, 2008 at 18:11

    Hallo pak Jimmy,
    Excellent and impressive pictures… I like it.
    I wuld like to sample your aikido sonic once you are OK.
    Then probably the next could be only a step away :
    How about trying out a Line Output Transformer (LOT) mode to replace the cap output mode ?

    Yrs sincerely
    PJ



  6. Jimmy Auw Says:
    October 9th, 2008 at 21:29

    Hello Pak Paul,
    Ok Pak, I will put her into the chassis first (well, I’m thinking at least temporary chassis since a good chassis needs some extra money). After that, we can arrange some time to benchmark her with your Aikido (or perhaps at Arif W’s place). I need suggestion what to improve also, since this is a really “cheap” Aikido…

    Thanks Pak.



  7. Kayak Says:
    October 23rd, 2008 at 20:08

    Wow man you’re playing with fire there… Build a tube amp need more knowledge about electronic and has to be careful to. And that never stop a tubelover like you, right? How about the sound of that “cheap” thing?



  8. Dani Says:
    December 15th, 2008 at 17:03

    Permisi Pak Jimmy kira2 kit AIKIDO di glodok ada yang jual nggak kalo ada dimana, mohon bantuannya



  9. Jimmy Auw Says:
    December 15th, 2008 at 21:28

    Gak ada yang jual Pak kit-nya. Mending bikin point-to-point aja.
    Thanks.



  10. gadut Says:
    December 31st, 2008 at 17:48

    Om Jim..kira2 abis brp budget nih ya ? boleh tau dong



  11. Jimmy Auw Says:
    December 31st, 2008 at 20:11

    Abis berapa? Lumayan banyak juga sih karena pelan2 di-upgrade dikit2… kira2 beginilah cost-nya dengan versi terakhir:

    PCB aja hampir US$ 50 sepasang, tambah shipping US$ 25.
    Component yang basic2 mungkin abis 600-750 ribuan.
    Output caps Obbligato around US$ 40/sepasang.
    Mundorf M-Lytic sekitar Rp 600-700 ribuan/3 pcs (2 di output, 1 di PSU)
    Tube 6N1P/6N6P total sekitar 300-400 ribuan
    Rectifier tube sekitar 200 ribuan
    Choke 3 pcs sekitar 200-250 ribuan
    Chassis+Trafokalo bikin mungkin 400-500 ribuan

    Harga di atas harga kisaran, karena saya sendiri sudah lupa harga pastinya. Silakan dicari/kontak ke toko2 yang biasa jual aja kalo mau tau pastinya. Toh semua komponen sudah terlihat jelas sekali, termasuk nilai dan mereknya.

    Thanks.



  12. Aries Says:
    January 24th, 2009 at 20:22

    Pak Jimmy,
    itu kabel signal yang putih/bening itu merek apa, kelebihannya apa, harganya berapa?
    Mohon pencerahan…



  13. Jimmy Auw Says:
    January 25th, 2009 at 21:41

    Itu kabel kawat putih biasa Pak. Di Glodok juga harusnya banyak, cuman 5000-10000 semeternya.

    Thanks.



  14. Anonymous Says:
    May 14th, 2009 at 20:53

    pak jimmy itu bersihinnya pakai air atau apa?



  15. Jimmy Auw Says:
    May 14th, 2009 at 21:14

    Bersihin apanya nih Pak?
    Thanks.



  16. Anonymous Says:
    May 15th, 2009 at 12:38

    bersihin komponennya yang pada korosi…



  17. Jimmy Auw Says:
    May 15th, 2009 at 21:31

    Dikerik aja pake gunting/cutter Pak. Abis itu gosok pake WD40 dikit, mayan koq.
    Thanks.



  18. Gary Divito Says:
    August 20th, 2009 at 12:35

    Hello Jimmy ,
    I am building an Aikido 9pin dual mono preamp as
    you very nice and using Duelund caps 1.0uf wow!

    I have a question you are using a custom power transformer what values for 6dj8 would you use?
    I see you used secondary is 300V-CT-300V (100mA), 3.25V-CT-3.25V (3A), and 0-5.25V (3A)
    that is for 0-220v primary what would be the values for 115v 50-60hz in USA.
    And what was the specs on chokes? Henry’s?

    Thanks as it would help much in my build.

    Great blog as i read all the time

    Best,
    Gary in Reno



  19. Jimmy Auw Says:
    August 20th, 2009 at 12:40

    Hi Gary,
    Nice to know you. Basically you need to “decide” first about your own requirement.
    - How much B+ voltage that you need? 6DJ8 should be fine with low voltage. Or you prefer to go with John Broskie table? Feel free.
    - The 0-5.25V/3A is for tube rectifier. Do you use tube rectifier also? You could download your tube rectifier datasheet to confirm the required voltage and amperage.
    - 6DJ8 should use quite low current. I think 3.25-CT-3.25 around 2A should be fine for 4 pcs of 6DJ8. You can go with 3A (but need to pay some more).

    Choke at least 10H, at least 50mA (go with 75 or 100mA). Higher is better also, but much more expensive.

    Thank you.



  20. boy Says:
    November 7th, 2009 at 14:58

    saya hoby banget ngrakit preamp tabung dengan cara ekstrem….



  21. Darius Says:
    February 23rd, 2010 at 04:04

    Jimmy,
    Nice site.
    I just finished putting SRPP+ together from John’s circuit board.
    I used 6n1P now I have one board AIKIDO and I also purchased Janus SOLO psu.
    I would like to use the same tubes as you are.
    This is going to be my line stage since SRPP+ will become my headphone amp.
    What would be the best combination of resistors for that?
    Thanks
    Darius.



  22. Jimmy Auw Says:
    February 24th, 2010 at 00:31

    Hi,
    Each resistor will produce different sound. I suggest you start with standard resistor first. Hear the sound, then start to change if you dont really like the sound.
    Thanks.



  23. hanjar Says:
    April 7th, 2010 at 16:49

    wah mantab nih pak jimmy bener2 do it yourself



  24. RIZal Says:
    June 4th, 2010 at 11:59

    OM JIMMY,
    sorry OOT, sy cr trasistor A1930-C5200 buat power ampli, tp di toko ditawari ada 2 mcm kluaran yg 17rb dan 50 rb perpasang, katanya suaranya beda jauh..
    kalo menurut om jim, apa betul ada 2 mcm kluaran dan hasilnya bisa beda jauh??
    mohon sarannya om..
    Thanks



  25. Jimmy Auw Says:
    June 4th, 2010 at 21:25

    Takutnya yg satu aspal Pak…



  26. ermac Says:
    June 21st, 2010 at 16:29

    pak jimm… solder goot cs 30 cari dimana ya pak??

    bisa beri referensi tokonya pak?
    susah carinya di sby
    thank u



  27. Jimmy Auw Says:
    June 22nd, 2010 at 18:22

    Di Glodok ada Pak. Di Sby saya kurang tahu.

    Thanks.



  28. Anonymous Says:
    July 6th, 2010 at 15:47

    pak jimmy sy masih bingung cara membersihkan mata solder sehabis pake…., kadang waktu menyolder timah mengumpal di mata solder tidk bisa merekat di PCB…
    1. itu kenapa ya pak kok ga bisa lekat di PCB?
    2. Cara memberishkan mata solder gmn n pake apa pak jimmy?

    thank u



  29. Jimmy Auw Says:
    July 7th, 2010 at 16:32

    Hi,
    PCB-nya dibersihin dulu pake Thinner, biar ga ada lemak menempel yang membuat solderan sukar lengket (atau solder kurang panas juga bisa).

    Bersihin mata solder pake kain agak basah aja, dilap gitu dalam keadaan panas. Atau pake tissue juga bisa.

    Thanks.



  30. Eko Pramono Says:
    August 7th, 2010 at 11:13

    Pak,..jimmy,..saya ada rencana membuat preamp mic tabung,…kira2x,..biayanya berapa,…preamp yg ingin saya buat yang mono aja,…mungkin ada advice buat saya,..

    Terima Kasih



  31. Auw Jimmy Says:
    August 7th, 2010 at 22:36

    Pak Eko,
    Biaya termahal mungkin di tabung dan trafo power supply-nya. Sisanya tinggal tergantung budget, pake resistor dan capacitor yang harga ratusan/ribuan Rupiah sampe puluhan/ratusan ribu Rupiah juga bisa.
    Mungkin minimal bisa habis 500rb sampai 1jt Rupiah untuk kelas menengah.
    Thanks.



  32. english al Says:
    August 21st, 2010 at 23:19

    hi, have just discovered valves and valve rectifiers….does does 5u3c tube upgrade have the same pin layout as the 5u4c tube???? ie can i just plug in the 5u3c straight into the 5u4c valve base???



  33. Auw Jimmy Says:
    August 22nd, 2010 at 10:07

    Hi,
    Yes, both are interchangeable. But I think, you have to check your filament heater power supply rating (must at least 3A).
    Thanks.



  34. english al Says:
    August 24th, 2010 at 01:30

    thanks for the reply:)..



  35. Jusup Says:
    August 12th, 2011 at 09:37

    Om jim..mo nanya gimana kualitas kapasitor russian pio k75 10 sy liat om jim pake yg teflon sy susah carinya boleh tau ga beli dimana..?…trima kasih om



  36. Auw Jimmy Says:
    August 12th, 2011 at 22:29

    Hi Pak Jusup,
    K75-10 lumayan bagus koq. Beda karakter ama Teflon.
    Saya belinya di eBay.
    Thanks.



  37. Stef Says:
    December 27th, 2012 at 04:02

    Jimmy!

    Hi, I’m Stef and I’m planning to build an Aikido linestage and I have a pair of 6H(N)6 tubes in mind for the last stage.
    But beinht very weak in mathematics I do not know how to calculate the operating point for this stage! The B+ tension has to be measured yet and that is important! Could I ask for your support when I know more?

    Regards, Stef



  38. Auw Jimmy Says:
    December 27th, 2012 at 22:19

    Hi Stef,
    You can check the manual from John Broskie. You can use parameter for ECC99. They are the same with 6H6N.
    Thanks.



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