Hi Ralph,Ralph said:
No, the BD136 does not need a heatsink. The LM317 stabiliser needs a little one (printed circuit type for instance) depending on the current the relays draw.
If your relays do not draw more than 100mA in total you can use a BC557 is stead of the BD136. But the BD136 is not expensive anyway.
Just want to let you know that the circuit works perfectly. I changed some minor things in the powersupply because of the spare components I had. And I didn't want the LM317 to dissapate too much so I used some resistors to drop 4v prior to the regulator.
Startup time is about 1m45s. I use two 2pole relays to switch on the 190V for the 5687 driver and the 460V for the 300B (both channels). Current draw is about 120mA. Voltage is stabilized at around 11.6v.
Ralph
Startup time is about 1m45s. I use two 2pole relays to switch on the 190V for the 5687 driver and the 460V for the 300B (both channels). Current draw is about 120mA. Voltage is stabilized at around 11.6v.
Ralph
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NiceThe resistor to lower the voltage on the LM317 is not necessary. The LM317 can easily dissipate the power in this case. 40-50 deg. C at the heatsink is no problem at all. Take care with such a resistor. With a small buffer capacitor the valleys of the ripple can become too low at the input of the regulator. You can check this at the output of the regulator with an oscilloscope. But anyway, it works.
By the way what are you switching? The HT directly or the filaments of the rectifying tubes? Best is to switch the filaments.
Hi Ralph,
100u – 30ohm – 100u leaves a too low voltage at the input of the regulator. This can result in a slightly humming sound from the relays. Either make it 220u – 30ohm – 100u or leave out the 30ohm (short it). A cap at the ref pin of the LM317 is indeed of no use for this application.
100u – 30ohm – 100u leaves a too low voltage at the input of the regulator. This can result in a slightly humming sound from the relays. Either make it 220u – 30ohm – 100u or leave out the 30ohm (short it). A cap at the ref pin of the LM317 is indeed of no use for this application.
Hi all,
I'm new to this forum and it looks good and more importantly friendly. I found this thread via a Google search because I was considering using the 555 as well to to remote delay trigger some new 2nd hand DIY tube monoblocks I bought recently. I'm new to tubes and was a SS man until I heard these vdVeen 4xEL34 design. I've got a vast background in loudspeaker design so maybe I can contribute in that area.
Anyway, newbie tube amp question. You need to delay the high voltage circuit and let the tubes glow first right? So the posted circuits will allow the high voltage to be relay switched after power up. What about shut down? Do you need reverse order delay in power down as well?
I'm assuming 12v from a PC will suffice as trigger source.
(Yes I'm probably a heretic combining high rez soundcard with tube amps)
I'm new to this forum and it looks good and more importantly friendly. I found this thread via a Google search because I was considering using the 555 as well to to remote delay trigger some new 2nd hand DIY tube monoblocks I bought recently. I'm new to tubes and was a SS man until I heard these vdVeen 4xEL34 design. I've got a vast background in loudspeaker design so maybe I can contribute in that area.
Anyway, newbie tube amp question. You need to delay the high voltage circuit and let the tubes glow first right? So the posted circuits will allow the high voltage to be relay switched after power up. What about shut down? Do you need reverse order delay in power down as well?
I'm assuming 12v from a PC will suffice as trigger source.
(Yes I'm probably a heretic combining high rez soundcard with tube amps)
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