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KT88 SE Basic or Master Kit

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Just so everyone knows as to the quality of this amp I'll post some pictures:

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Construction will begin later on today sometime after I stop having a heart attack from yesterdays bull, I'll have to wing it in regards to the upholstery because I want this thing finished by christmas, its my christmas present to myself.

No matter how tempted I am to try those UK handmade PIO capacitors in my DAC.

I should be able to fit the upholstery after its assembled, lifting of the transformers inorder to get it underneath, etc.
 
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Feel like I've been on a passenger train for the last 7 hours.

You might notice that I didn't use the included 9-pin socket, I instead stuck a Russian Ceramic 9-pin socket in there, the way I figured it I wanted a Russian Socket to go with a Russian tube, and I just love Ceramic, even though Plastic does survive better, I still have nightmares of cracked bakelite sockets from amplifiers and radios in my past.

Here are some pics while I take another break and eat dinner:
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You state that I need to connect a 100k 2 watt resistor to the B+ to discharge them after testing.....On page 39.

However there is none supplied with the kit.

So rather be safe than dead I shorted the capacitor with a big nasty ugly very well insulated screwdriver, it was sitting at about 450vDC at the time. (this was done while waiting FOREVER for them to slowly discharge with the kit disconnected from the mains...)

Needless to say my ears rung afterwoods....:eek:

I strongly suggest that some sort of bleeder resistor is put in place before the capacitors are shipped so this kind of stuff doesn't happen again. :)

Whats the word on these capacitors being damaged, and by that I mean the two big assed 50uF capacitors?

Nothing else looks or smells damaged, not even the two leads coming from the other capacitor.
 
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Btw the voltages have all checked out:
771vAC for the unregulated AC B+
376vAC for the half CT B+
376vAC again for the other half.
5.5vAC for the Rectifier filament.
6.43vAC for the main filament bus.

and 551vDC for the filtered DC B+

My mains voltage is probably a little low here so that would explain the slightly lower readings than spec.
 
Well just about ANY high-value resistor would have been better that direct shorting them with a screwdriver. The caps are probably OK, but I would not suggest doing it that way again.

When the circuit is fully wired, the caps will bleed down very quickly after power is removed.

Maybe I should include a bleeder resistor, however the capacitors are not charged when I ship them. No reason to put a bleeder resistor in place before shipping. I've never bought a cap that came with a bleeder resistor pre-attached.



You state that I need to connect a 100k 2 watt resistor to the B+ to discharge them after testing.....On page 39.

However there is none supplied with the kit.

So rather be safe than dead I shorted the capacitor with a big nasty ugly very well insulated screwdriver, it was sitting at about 450vDC at the time. (this was done while waiting FOREVER for them to slowly discharge with the kit disconnected from the mains...)

Needless to say my ears rung afterwoods....

I strongly suggest that some sort of bleeder resistor is put in place before the capacitors are shipped so this kind of stuff doesn't happen again. :)

Whats the word on these capacitors being damaged, and by that I mean the two big assed 50uF capacitors?

Nothing else looks or smells damaged, not even the two leads coming from the other capacitor.
 
Well just about ANY high-value resistor would have been better that direct shorting them with a screwdriver. The caps are probably OK, but I would not suggest doing it that way again.

When the circuit is fully wired, the caps will bleed down very quickly after power is removed.

Maybe I should include a bleeder resistor, however the capacitors are not charged when I ship them. No reason to put a bleeder resistor in place before shipping. I've never bought a cap that came with a bleeder resistor pre-attached.

The amp is working fine, I'm listening to it right now and have been for 15 minutes.

Indeed, but your instructions state to test the B+ without output tubes installed, then magically produce a resistor that will discharge it before continuing further, check carefully page 39, you will notice that this B+ test is done with just the rectifier tube in place.

All I had available was 1/8 watt ones and I wasnt confident in their voltage ratings, and I didn't feel like hooking up a 10 ohm or 5 ohm 5 watt ceramic resistor to a 450vDC bus and watching it blow up as thats all that I had in the large value ranges.

Anyway, a cautionary tale best left for some other time and some other place.
 
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Indeed, but your instructions state to test the B+ without output tubes installed, then magically produce a resistor that will discharge it before continuing further, check carefully page 39, you will notice that this B+ test is done with just the rectifier tube in place.

Well, the very first page of the manual states:

PLEASE READ THIS MANUAL IN IT'S ENTIRETY BEFORE BEGINNING ASSEMBLY

I'm glad you've got it working. That was a pretty quick build.
 
Well, the very first page of the manual states:

PLEASE READ THIS MANUAL IN IT'S ENTIRETY BEFORE BEGINNING ASSEMBLY

I'm glad you've got it working. That was a pretty quick build.

Yes, I missed the ATTENTION at the bottom of page 38, or rather that I did read it but quickly forgot its meaning.

Which states that the power supply capacitors will discharge rather rapidly with all tubes in place.

Anyway the bottom cover is on, the earth lead is safely attatched to the chassis and its sitting on my desk here playing away.

Thank you :)

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