Amplifier on tubes "Bachelor"

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Zampotech, Oct 9, 2019.

  1. Zampotech

    Zampotech Friend

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    Dear friends

    I want to announce a new project. Conditional name "the Bachelor"
    The aim of the project is to create a SET budget amplifier. It is no secret that there are many young people at the forum, University students who do not have a steady income.

    I want to create a new amplifier on two inexpensive tubes, with a simplified case, but full electronics.
    The Moscow company offered me to purchase the reserve balances from the production of another amplifier, and this allows you to create a new amplifier weighing about 2 kilograms and costing about $200 (this is an estimated cost, the exact cost is not yet known)
    Weight up to 2 kilograms is important because the post office defines it as "small package", it reduces the shipping cost (For example for USA the shipping cost will be $34)

    Of course, it will not be an extra-class amplifier. But this amplifier allows you to introduce the student to the amplifiers on the tubes.

    To date, I have completed a mock-up sample and convinced myself of the reality of this project.

    If I started this thread in the wrong section, please moderators correct me.
     
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  2. Lyander

    Lyander Too sensitive for SBAF

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    Upvote for the name alone, hah!

    Would be interested in hearing from you (or an unbiased third party who has the other amp on hand ;)) how this new baby compares to the SW51 in sound, since it seems they're quite similar in theme from your description.

    Then again I know nothing of electronics. High probability I'm missing something simple.
     
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  3. Zampotech

    Zampotech Friend

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    I want to know, too. I will provide a pre-production sample "Golden ears SBAF" and after the final evaluation will draw conclusions.
     
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  4. Zampotech

    Zampotech Friend

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    First information with pictures

    The first case for the amplifier in the style of "Boots". Unfortunately, the calculated weight exceeds the required 1800 grams by 300 grams. 6z1p tube (5654 and EF95 analogs)

    [​IMG]

    For scale SW51 and " Bachelor"

    [​IMG]

    Wood and plywood will probably need to be used to reduce weight.

    The amplifier housing for students should be more vandal-resistant. Anything can happen in the atmosphere of General fun of the student hostel [​IMG]

    I think the "Bachelor" could be one of the tiniest SET amps.
     
    Last edited: Oct 12, 2019
  5. famish99

    famish99 Friend

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    @Zampotech How much weight would you save by getting rid of one of the outputs so that you only have one plug and one secondary? The single tube design doesn't really have the power output for most low-Z headphones other than the Focal, which aren't exactly cheap and even then I preferred them out of the high-Z output anyway.
     
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  6. Zampotech

    Zampotech Friend

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    If i remove the second out, I will reduce the weight by only 20 grams. And lose the useful option " second load"

    This amplifier is not OTL, has transformers that allow you to align the headphones with the amplifier.

    I have not yet figured out how to reduce weight, but this option will also live. Russian students also do not have a surplus of money

    Although preliminary measurements showed that the amplifier has very decent characteristics.
    Lower frequency - 23 Hz (-1 dB / load 40 ohms)
    Upper frequency - 24 kHz (-1 dB / load 40 ohms)
    THD has not yet measured, but no visible distortion has been detected

    Of course, no one has ever listened to him on headphones
     
    Last edited: Oct 13, 2019
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  7. Walderstorn

    Walderstorn Friend

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    Just shooting blind a little here but how much does that front plate weight?
     
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  8. Zampotech

    Zampotech Friend

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    Estimated weight 62.4 grams. Counting from the volume of the part and the density of the material.
    Of course, the panel is heavy.

    Good idea, thank you. Probably need to be replaced with a lightweight aluminum panel 3 mm thick.
     
    Last edited: Oct 13, 2019
  9. Walderstorn

    Walderstorn Friend

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    I was counting on it having 100 ish...would replace it with something much lighter but i guess that's a futile thought now. I think that plywood front, side and bottom would help a ton, if the bottom panel is not providing much support to anything.
     
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  10. Zampotech

    Zampotech Friend

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    I recently finished designing this amp and made a mock-up sample. I have certainly not Golden ears, but the sound of this kid I really liked.
    THD measurements showed a short distortion spectrum, small in magnitude. But the measurement was done by simple instruments. Hopefully more accurate measurements won't be much different from my measurements.

    This is what the first "Bachelor" looks like:

    [​IMG]

    This kid has the most real output transformers. Transformers Moscow firm, used in the amplifier NBM (probably in ZDT-Jr similar transformers, I modestly did not specify the manufacturer)

    [​IMG]

    Manufacturer NBM proposed to call this amplifier "Night Blues Micro". I'm still in a quandary [​IMG]
     
    Last edited: Oct 29, 2019
  11. Walderstorn

    Walderstorn Friend

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    I would not call it "night blues micro" but something meaningful to you. At first glance when i started to read i thought u would call it "the kid" hehe
     
  12. Zampotech

    Zampotech Friend

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    I agree with you. The name in NBu is not bad, but does not really correspond to the appearance. So far I call it almost as you suggested, but in German, "Kind (er)"
     
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  13. Zampotech

    Zampotech Friend

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    Update.

    In China PCB are made for this amplifier and go to me. 12 amplifiers takes two Moscow stores. 15 pieces will be available. The cost will be $270 free shipping (fast courier delivery to any country) It is possible to order several pieces
    Or $310 when selling through eBay (ebay Commission more than 12% :()

    I don't want to make the amplifier more expensive, so the potentiometer is only ALPHA (as in NBM/ZDT-Jr). My opinion is a good potentiometer.
    In the first batch, each amplifier will have two spare tubes.

    The amplifier is available to forum members and future forum members (guests)

    Undoubtedly, the amplifier will be given to the forum for testing.

    If you are interested in this amplifier, download the pre-order and send me an e-mail (mail is indicated in the form)

    Sending an order does not oblige you in a mandatory purchase.

    I hope these amps get into your house this year, by Christmas
     
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  14. MisterRogers

    MisterRogers Ethernet Nervosa

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    Earlier you were thinking on materials to use for a lighter case. What did you decide on?
     
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  15. Zampotech

    Zampotech Friend

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    Now I'm going to make completely out of steel. Is obtained weight about 2,500 grams.
    I wanted to use aluminum, but the calculation showed that the aluminum housing is very expensive and therefore not suitable for a budget amplifier.

    A little later I will experiment with plywood elements. I consult with an experienced restorer of antique furniture, perhaps he will tell me convenient options

    I like this amplifier more and more. He has some unrealistic characteristics. For example, the output impedance is 2.5 ohms (L out) / 7 ohms (H out)
    Noise and background are not detected by my instruments. Of course, the @atomicbob lab can determine this parameter, but I can't, it's below the sensitivity threshold of my instruments. My instruments cannot reliably measure below-75dB

    I had a wonderful professional psophometer, but I foolishly swapped it for a wonderful oscilloscope. Now I have about 6 oscilloscopes and no psophometer.
     
    Last edited: Nov 4, 2019
  16. Walderstorn

    Walderstorn Friend

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    I think, and looking at some amps, as the Crack, for example, a plywood (compound) housing with a metal plate on top, where to screw most components will make it more accessible, or am i wrong?
     
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  17. Zampotech

    Zampotech Friend

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    No, you're not wrong. It's really easier and cheaper. But the first batch of amplifiers shops ordered it in a metal case.
     
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  18. Dzerh

    Dzerh Friend

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    @Zampotech, sorry, can the delivery to US happen before New Year?
     
  19. Zampotech

    Zampotech Friend

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    Chance of course there is. I plan to finish manufacturing and start shipping on December 7-10. Sending only fast EMS.
    For USA, the shipping time is 10-20 days, average 14 days.
     
  20. Zampotech

    Zampotech Friend

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    The first photos of the serial amplifier. The amplifier does not yet have a front panel.

    [​IMG]

    Internal organs of the amplifier

    [​IMG]

    This little scoundrel has a flat frequency response from 21 Hz to 113 KHz and a very low output impedance.
    Below 21 Hz I can't measure my measuring technique doesn't allow it.
     
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