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siriuz

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Posts posted by siriuz

  2. Posted · Report reply

    @kube: i was thinking to leave at 4pm after the talk by electrical and electronic engineering, but i think i'll sit through media and info comm, then meet you? i think this friday we head down to koba instead, you want to get all the parts and the amp parts also right? i didnt see any tube sockets at slt today

     

    actually i bought ferric chloride and blank double sided pcbs today. wanted to surprise you guys tongue.gif

  4. Posted · Report reply

    yea i know can make with 4 diodes. i'll be going down to sls prolly this friday after SP career fair, so its ok =P i'm in no hurry, since the tubes aren't here yet. i was thinking 3VA like very weird leh, i do some mental calcs turn out like only around 0.1A. so i dunno why it write 0.3A. so i bought the 6VA one lor

  6. Posted · Report reply

    oops i forgot about da blok blush.gif

     

    but nvm la hahaha i got the parts liao.

     

    total about $15 for the psu.

     

    i intend to use IEC socket for connecting, then can use the same power cables as computer. the sockets can get at sls most shops. koba should have also. i couldnt seem to find 11k resistor in sls so i got 2 x 22k to parallel instead.

     

    heater is powered by the ps, but its part of the tube. two of the pins on the tube, its not a separate unit.

  7. Posted · Report reply

    oh ok!

    i thought it'd be getting the full 30v blush.gif

     

    i mean, i'll be putting it together with the amp side because it'll be on the amp board. it'll still be tapped from the heater supply. yes i want a mean blue glow lighting up my tube smoke.gif

  9. Posted · Report reply

    i going down to sls tmr to get the parts for the psu section, will finish psu section tmr, then wait until tubes arrive then i work on the other part.

     

    heres the parts list i've worked out for the psu section:

     

    4 x 100uf 100v electrolytic caps

    3 x 470uf 35v electrolytic caps

    3 x 47uf 16v electrolytic caps

    2 x rectifier bridges

    2 x 1N4002 diodes

    1 x 15-0-15 200mA transformer

    1 x 7812 12v regulator

    1 x 7912 -12v regulator

    1 x LM337 regulator

    1 x 2W TO-220 heatsink (for LM337)

    1 x 2k2 resistor

    1 x 1k3 resistor

    1 x 11k resistor

     

     

    the 470uf caps i was thinking 35v abit low since 30v x 1.41 is 42.3v

    so i'll probably get 50v ones instead, dont think they'll cost alot more and it wont hurt either

     

    if you're wondering where the RLED and the LED went, i decided to put it in the amp section

     

    if there are any mistakes in the parts list please let me know blush.gif

  11. Posted · Report reply

    yea from what i've seen of the pictures and what i've heard in the thread, both squalle and kippei using "stripboard". not really "stripboard" since the traces are not strips? i think they're using perfboard / veroboard / <insert variant here>.

     

    i dont think its really that complicated if you lay it out nicely on paper first =P

     

    since it intrigues you, why not try it? biggrin.gif

  13. Posted · Edited by siriuz · Report reply

    hey squalle, you asked why NOS tubes were preferred? i came across this tube FAQ on headfi during some googling wink.gif

     

    3.4 $3000 for a single tube??! Why are some NOS tubes so expensive?

     

    The short answer - supply and demand.

     

    The long answer - Some tube amps are quite old, and their owners may prefer to maintain a completely `vintage' setup. Others believe NOS tubes sound better. Others are simply sheep with too much money to throw around who jack up the prices.

     

    The NOS tube supply by its very nature finite - and dwindling each day. Some NOS tubes are very much sought after and are hence in particularly short supply. All these factors contribute to the much higher prices of NOS tubes when compared to plain new stock tubes.

     

    You may want to consider what types of tube an amplifier uses before purchasing it - this WILL more or less determines the scale of your future expenditure when re-tubing the amplifier.

     

    3.5 Do NOS tubes really sound better?

     

    NOS tubes are reputed to sound much better than new stock tubes. The author of this guide believes, to a certain extent, that this is true. There are many theories floating around as to why NOS tubes sound better. I have cherry-picked a few that I am certain have at least a grain of truth in them.

     

    1. The 1930s-1950s were the golden era of tubes. Equipment used to manufacture tubes and more importantly, skilled people to operate them were plentiful. All of these have been lost with the advent of the transistor and automation.

     

    2. Tube R&D has come to a virtual standstill since the 1960s.

     

    3. When compared to transistors, tubes are relatively expensive and time-consuming to manufacture (to achieve a good vacuum for a SINGLE tube, some vacuum pumps run for as long as 3 days!). In the highly competitive niche market for new stock tubes, quality may not be the top priority anymore. One amplifier manufacturer has been quoted as having to reject 1 in 4 6AS7 tubes for bundling with their amps due to unacceptable levels of microphonics/hum/channel imbalance!

     

    Even then, it is strongly recommended that you try at least a few tubes of recent make before putting down some serious money for NOS tubes. Typically for the price of a single NOS tube you would be able to obtain at least 3-5 new stock tubes. You never know what you might stumble across...

     

    read the whole FAQ here: http://www4.head-fi.org/forums/showthread.php?t=121357

  16. Posted · Report reply

    oh ok i think i'll start laying out the psu later. many people seem to have hum issue and most of it seems to stem from trafo placement. so i think i'll have the psu and the amp unit on separate boards and possibly in separate cases

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