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Posts posted by charlo89

  1. I hade the banned screen 4 or 5 times on my phone on 4G (without be logged in) and once on my PC. It started around the end of December. I tried to clear my cookie or changed the browser nothing works. I just waited a couple of minutes and it works again. 

  2. I forgot to thank you.
    I don't have 150k resistance in stock, anyway I need to order some components from mouser, I will do the mod on my return from vacation. 

    Do you have any idea why the amp has a second version ? 

  3. On 12/2/2016 at 0:14 PM, valve5425 said:

    Looks like you worked it out yourself! I guess you could populate the board normally and fasten it upside down to the top panel of your chassis. Then use short wires from the bottom of the board to tube sockets bolted to the underside of the top panel. However that raises the problem of adequate heat sinking as they don't tend to work too well upside down! Maybe you could use something like a http://uk.farnell.com/amec-thermasol/mhp-1220a-100a/heat-pipe-ultra-flat-1tx100l-mm/dp/2290468 to replace the big sinks, (you'd need to size that appropriately) fastened between regs/mosfets and the top panel.

    But then it's getting complicated and you'd probably be better just getting modified boards made, or use connectors like I did!

    Thank you for your answer, I think I will use this PCB 


    This socket www.ebay.com/itm/1PC-High-Quality-Ceramic-9Pin-B9A-Vacuum-Tube-Socket-For-12BH7-12AU7-ECC83-EL84-/191688017575?hash=item2ca17f06a7:g:ZkAAAOSw5dNWmODJ

    Fix everything to the chassis with this http://www.ebay.com/itm/2PCS-34mm-12AU7-Vintage-Tube-Audio-Matting-Machined-Aluminum-Decorative-Ring-DIY-/201496427354?hash=item2eea1f7b5a:g:eX0AAOSwKtlWij~P

    And wire the tube pcb to the KGST pcb with a molex connector as you did :)

  4. 20 minutes ago, johnwmclean said:

    Or just put the tubes on the underside... much easier than all the other components. :P 

    My board was not design to put the tubes on the underside, and the 6S4A is a 9 pins socket, I can't flip it with the same layout

  5. thank you :)

    I think last question, Can I flip all component on the other side of the boards to get the tube almost alone on one side ? All component exept no flipable component like the lsk389 or the STN9360

  6. Thank you,

    The MPSA will work fine ? it's the 625mw version of the MPSW, the  NTE128P has a fd of 850mw it's more closer to the 1W of the MPSW06.

    I don't find many information and DIY use for the NTE128P. MPSA06 will be better ?

  7. Are you sure that the channel is dead and it is not a switch issue?  Measure the top of the large resistors for DC voltage.  You should have roughly 0VDC between them and each one relative to ground is +290VDC. 


    Replacement parts for the output devices are all but impossible to source.  You need low Cob which is the truly hard part. 


    Did you fix the problem?


    Sorry for the delay, and thank you for your help.

    I was in paris for two months, and when I come back the amp worked, I adjusted the offset and checked the DC voltage between the resistors, I found +6v on the left channel, +3V on the right channel, and arround 285-295V between the resistor and the ground.

    I bought a SRM-727A last week and I found +12V between R+ and Ground, it was very difficult to adjust this tension to something under 1v, it was the same for R+/R- L+/L- and L+/Ground.

    I do not know if this is normal, but I found +290V between the Bias and the ground for the 727A and +360V between the bias and the ground for my SRA-12S. (on the jack for both)

  8. I have a problem with my 12S.

    It's a restored unit with a Pro bias made by spritzer.

    But one channel is dead, the problem comes from one of the board with 2SC1167 transistor.

    The amp took time to die. First, there was like an interference noise on the left side, and sometimes it disappeared. After a week of use, the channel stop working and trade the intereference noise for a buzzing noise with a very low sound.


    I want to know which component is likely to die on that board?

    I don't have the knowledge to detect a defective component. What step I should follow?.


    Thank you  

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