DYNAKIT

Discussion in 'Thiết bị khuếch đại' started by hung6310i, 30/1/06.

  1. hung6310i

    hung6310i Advanced Member

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    Xin loi cac bac may em ko dung hdh Window nen chua tim ra cach danh tieng Viet
    Nho may bac cho biet thong tin Dynakit ST70 Va cac doi cua chu amply den nay nhe
    gia bao nhieu thi hop ly
    cm onn cac bac nhieu
     
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  2. busuavoi

    busuavoi Advanced Member

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    Thong tin nay co huu ich gi cho bac ko?



    Dynaco ST70 Stereo Tube Amplifier:
    Here is a tube amp that is easy to own, easy to enjoy.


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    HE Dynaco or more aptly the Dynakit ST70 is a wonder. Aimed at a budget price point and premised on delivering the most value for the buck, its parts quality was average. The quality of assembly was erratic and varied with the dexterity of the do-it-yourself kit assembler's hands. Yet, even after 30 years of service, many ST70s continue to provide musical satisfaction to their second, third, or even fourth owners. One would think that these ST70's would have died long ago. Their reliability is a testament to conservative design and execution. It also makes one wonder why some of the high end components of recent times don't have the same longevity, despite the use of higher quality parts, improved manufacturing techniques, and advanced circuitry.
    Ubiquity

    Many tube audio enthusiasts have had at least a brief acquaintance with the ST70. It was like a rite of passage before moving on to greater (meaning expensive) and more sophisticated equipment. I frankly believe it is a great starting point to learn tube audio maintenance such as biasing, tube replacement, troubleshooting and modification, if one were so inclined. I've listened to least half a dozen of these amps. Some I have owned for a time, others were owned by friends. It's the amp that gave me the confidence to dabble into tube audio. I found out that tube components are more "friendly" and easier to troubleshoot than the silicon-based units.

    Packaging

    The ST70 will not win any aesthetic design award--it was not designed to be decorative. It has a nickel-finish chassis with vinyl charcoal brown cover. With its HWD dimensions of 6.5 x 9.5 x 13 inches, the amp looks like a small box. Not to worry, this boxy look afflicts many tube amps. I frankly prefer not to have the cover on and marvel looking at the tubes as they glow in the dark. But then, I have no pets to worry about. The shipping weight of the unit is 32 lbs. The ST70 has an output impedance of 4, 8, and 16 ohms. There are socket provisions to power an external preamp. I have never had any use for these however. The bias points are conveniently located in each of the sockets. You do not have to open the unit to bias the output tubes like some tube amps. There is also a stereo-mono switch.

    The amp has a tube complement composed of: 4--EL34's, 2--7199's, and 1--GZ34 selenium rectifier. The 7199's are no longer in production but one can still find these from tube dealers and individuals. For reliability, the output tubes are said to be operated at 65% of capacity, the filter capacitors at 85% of rated voltage. The ST70 is said to deliver 35wpc. I have seen many reports contradict this power rating, stating instead that this is in the 20-25wpc.

    Associated Equipment

    The following components were used to evaluate the ST70: Audible Illusions Modulus 3 tube preamplifier, JVC XL-Z1050 compact disk, Sound Dynamics 300Ti, Linn Kan II and mostly with the Rogers LS3/5a speakers. Prior to reviewing the unit, I had the system playing for about two hours.

    Listening pleasure

    I had just recently been listening to transistor amps. Right away I could distinguish the difference. The ST70 provided the bloom, fuller sound, and body reminiscent of tube equipment. One does not have to search for these. They are there to be enjoyed.

    The amp like most of its glowing siblings excel in the midrange and vocals. Joni Mitchell's singing in her Blue CD (Reprise 2038-2) was a joy to listen to. There was not a residue of dryness. Kung Wha Chung's rendition of the Beethoven Violin Concerto (Decca 400 048-2) became much more involving. The violin was so eloquently captured as was its interplay with the rest of the orchestra.

    It is not that the amp shed more light or provided more illumination. No, there were not many more players that could be heard. From the darkness of the soundstage, there was the illusion of space among the players. This spacing among the players provided dimensionality but also less detail and shading as a consequence.

    Weaknesses

    Against better tube and transistor components, the ST70 shows its age and compromises. It lacks dynamism, high frequency detail, quickness and low-end wallop. True, one can hear the highs but not the extended highs. And the highs do possess some granularity.

    It does not also have a deep soundstage. I've heard units with beefed up power supply and expensive passive parts with virtually no improvement in soundstaging. It's bass is also deficient. It cannot reach deep down and provide viscerally moving bass.


    A must own tube amp

    I'm afraid I've been too hard on this amp. I am comparing the ST70 with those costing over ten times as much. In the context of today's sky high prices, its almost a miracle that one can find solace with a humble amplifier that costs between $150-$200 at current street prices. Aren't we lucky that we still have the Dynaco ST70 to kick around and enjoy. I almost always keep one in the house because these amps are too cheap and too useful to be without. They are getting rarer by the year so keep what you can get. Recommended. Two clefs.


    by Judy Cipriani




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  3. busuavoi

    busuavoi Advanced Member

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    Gia hang secondhand tren eBay la $145
     
  4. busuavoi

    busuavoi Advanced Member

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  5. quyda

    quyda Advanced Member

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    Các bác gõ tiếng Việt có dấu cho bọn em nhờ chút nhé!

    Em cũng từng tìm hiểu còn này, các bác sẽ phải thay bóng, vì loại bóng ngày xưa không còn nữa, 1 bác khác nói là thiết kế amp ngày xưa không còn thích hợp với các thiết kế hi-fi ngày nay nữa, em cũng chưa hiểu là khác thế nào?

    Kính các bác
    Quyda
     
  6. Libra

    Libra Moderator

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    Cái này âm thanh hay trong tầm giá. Công suất cũng tương đối. Dùng đèn khá phổ thông nên dễ thay thế. Đèn công suất là EL34 thị trường có sẵn giá khá hợp lý. Giá tại VN thì chắc là cao hơn giá nói trên.
     
  7. BachDuong

    BachDuong Moderator

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    ST70 hay là do cặp xuất âm và cục nguồn làm từ một loại lõi thép nặng đặc biệt do Dynaco đặt hàng một công ty chuyên quấn biến áp ở Chicago làm. Hiện nay loại lõi thép đó không còn sản xuất nữa nên người ta hay săn mấy amply cổ của Dynaco, Heathkit... chủ yếu để lấy xuất âm. Giá bán một cặp xuất âm của ST70 tháo máy trên Ebay cũng trên trăm đô rồi. Bộ Dynakit trên mà có giá $145 là quá hợp lý đấy các bác à!

    Nhưng các bác lưu ý là xuất âm của ST70 có 2 loại, một quấn tay ở Mỹ và một quấn máy ở Nhật. Loại quấn máy ở Nhật thì không được đánh giá cao lắm.
     
  8. Hamcq

    Hamcq Advanced Member

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    Hi
    Có khá nhiều bài viết về cách mod ST70. Đáng chú ý là cách mod bộ nguồn, chọn và thay bóng driver, lắp thêm nguồn dòng hằng để giảm méo tầng driver...Nếu biết chút đỉnh về điện tử thì việc nâng cấp ST70 là không khó.
    Cheers
     
  9. hung6310i

    hung6310i Advanced Member

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    Cam on cac bac rat nhieu nhung thong tin tren la cuc ki bo ich doi Voi em
    Theo cac bac thi trong khoang 4 den 5 tr thi em nen choi amply den cua hang hay la do lap tay
    Xin loi cac bac em ko go dc tieng Viet
     
  10. DũngAudio

    DũngAudio Advanced Members

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    :p kiếm được 1 cái còn đẹp ở nước ngoài theo em thấy khoảng 300 usd . ở vn nếu có cũng khảng 450 - 500 . ở gía này thì dynaco hay dynakit đều rất khá. tất nhiên phãi thay thế 1 chút vài con tụ dưới chân đèn để cho cái bóng el34 đở mệt mỏi ...nên nghe sẻ hay hơn
    mấy cái chân đèn st 70 chất lượng rất tốt , bóng 7199 nghe khá hay nhưng hơi khó tìm. nếu đèn nguồn còn được cái bóng gz34 là nhất rrồi

    dynakit( dynaco) hay luxkit( luxman) đâu đó cùng 1 đời với nhau. luxkit nhìn đẹp hơn . nhưng trên cái nghe thì dynakit có phần nhỉnh hơn về sự mềm dẻo giữa 2 nhạc từ hoặc 2 nốt nhạc :wink:

    st70 cải tạo lại 1 chút nhìn cũng đở lắm chứ :p
     

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  11. hung6310i

    hung6310i Advanced Member

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    Chào các anh ,ông anh em có thể nhập xuất âm của dynakit nhưng em ko biết anh em mình ở đây cho gía như thế nào thì hợp lý để em làm việc vớy ông ấy
     
  12. Rumbeng

    Rumbeng Advanced Member

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    Có khi bác qua chủ đề " OPT của hãng " , post vào trong đó hơi cụ thể tí như bao nhiêu ký, PP hay SE , thì chắc sẽ có thông tin hơn .
     
  13. hung6310i

    hung6310i Advanced Member

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    cảm ơn bác hứơng dẫn em sẽ làm theo lời bác
     
  14. lamdoi

    lamdoi Advanced Member

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    Hehehehe em mới lụm được cục Dynakit 70, mạch còn gin :D, đang xài đèn EL34

    [​IMG]

    Hehehe các bác cho em hỏi là em có thể thay đèn 6550 vào được không ạ :D. Cám ơn các bác nhiều :mrgreen:
     
  15. tai_trau

    tai_trau Moderator

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    6550 em tưởng thay cho kt88 bác ới.
    mà sao bác đi chợ hay thế kô bít.
    bác sướng thật đấy. ngon quá.
     
  16. lamdoi

    lamdoi Advanced Member

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    Heheheh vâng, ngẫm đi ngẫm lại thì hình như đồ nó tìm em bác ợ :mrgreen: . Túm lại là hem thay được hả bác tai_trau :?: .

    Hehehehe cái MMC-4 em thấy toàn trên trăm không bác ơi :( .
     
  17. tai_trau

    tai_trau Moderator

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    Vưng, em e là hổng thay đc.
    Em cũng theo mấy cái MMC4, mà ko nổi vì cao quá. 1 tiền gà 3 tiền thóc.
    Vẫn phải mai phục đợi vậy. Bác ở bển thấy có thì chộp giúp em, em đội ơn bác.
     

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