new build 36lite with vvr

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chaliapin
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Re: new build 36lite with vvr

Post by chaliapin »

Great thanks. Just to clarify, one in each side of the power section, it's the shared grid connection on pin two that makes them a pair?

Might get sone NOS Russians from Ukrainian sellers, you used them bieworm?
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chaliapin
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Re: new build 36lite with vvr

Post by chaliapin »

I decided it did, as each pair gets fed from either side of the phase inverter.

Unfortunately something is wrong as with two power tubes and speaker connected the limiter bulb is bright and the indicator light not lit with power on but standby off. There was 6v on the power heater pins (without the bulb limiter) without tubes in and all fine with only the pre amp tubes.
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chaliapin
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Re: new build 36lite with vvr

Post by chaliapin »

So im seeing around 160v pins 1 and 6 of v2 the PI with the limiter so that seems right. But I'm seeing nothing after the next caps c7 and c8 so then nothing at the power tube sockets pin 2, I should be seeing a negative DC there right? Have i got the caps reversed?
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Re: new build 36lite with vvr

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chaliapin wrote:
Thu 01/12/23 2:51 am
Great thanks. Just to clarify, one in each side of the power section, it's the shared grid connection on pin two that makes them a pair?

Might get sone NOS Russians from Ukrainian sellers, you used them bieworm?
Correct. From the 10 I bought 2 were bad… still a real bargain
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chaliapin
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Re: new build 36lite with vvr

Post by chaliapin »

Well everything seems perfect until I put the two power tubes in, then lamp bright with the standby still off, is that definitely the heater circuit? The heater voltage is present and correct on the power tube sockets without the tubes in - 3-4v with limiter. Ive tried switching around my three remaining power tubes. All same result. Any ideas?
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Re: new build 36lite with vvr

Post by Bieworm »

If there was a short in the heater circuit you would notice it even without tubes. You wrote that with only the preamp tubes in there all was fine? So the heaters are not the problem IMHO. There is a problem with the power tube wiring. You didn’t wire the OT primary center wire to ground instead of the filter cap?
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Re: new build 36lite with vvr

Post by chaliapin »

Is that the red one?
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Re: new build 36lite with vvr

Post by chaliapin »

So I am using a20w halogen limiter bulb, I began to suspect it was glowing brighter with the power tubes simply because they were drawing more current. Anyway, I tried without the bulb, there was my 6v heater current all present and correct! So got over excited, turned the standby on with speaker plugged in and and a cap exploded. One of the ones in parallel with the big resistors going to ground in the power section.

Got extra sad after that. Not sure exactly what to do next.
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Re: new build 36lite with vvr

Post by Bieworm »

hang on man! ;)
post some detailed pics from different angles, especially the power amp section, ground connections,...
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chaliapin
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Re: new build 36lite with vvr

Post by chaliapin »

chaliapin wrote:
Sun 10/30/22 5:40 pm
Not planning a can cap either...

Attached what I have for the PT.Image

Sent from my SM-J600FN using Tapatalk
I'm trying to check everything im at all unsure about. I have the screen going to ground same place as the heater ct resistors. Correct?

White should be connecting with the live/ brown from the mains, blue with the blue/ neutral. Correct?
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Re: new build 36lite with vvr

Post by chaliapin »

I'll get onto the power section but I'm back to working with the standby off. With only the rectifier tube, in my voltage at the power switch drops from 230vac to around 160 when I switch on, this is with the lightbulb limiter. That's not right is it?

Edit.
Although, with standby ON, I AM getting 260v dc at point A of the schematic which is my b+ right? Same at pin 7 power tubes which is probably going to approach the 320v DC I'm looking for once I remove the lamp right?

Double edit.
Changed for a 45w bulb, mains and b plus now all as they should be, also much clearer when it's bright and when it's dull...20w was too low.
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Re: new build 36lite with vvr

Post by chaliapin »

Went very slowly and carefully back through the rob startup procedure. Got to tell you people IT'S ALIVE! IT'S ALIVE! MAKING NOISE! OH YEAH!

Now, I've only plugged in with the two power tubes in and still with the light bulb limiter. It didn't sound good but it sounded fine. Pin voltages all good except I don't have ANY voltage pin 3 power tubes where my sheet says I'm looking for 11 volts. Im going to try to stop myself removing the light bulb limiter until one of you kind people reply to me... please don't leave me too long!
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Re: new build 36lite with vvr

Post by JMPGuitars »

The light bulb limiter is to test for shorts. If your amp works and you're not seeing any shorts, why would you keep the light bulb limiter in use?
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Re: new build 36lite with vvr

Post by Bieworm »

chaliapin wrote:
Fri 01/13/23 2:11 pm
Went very slowly and carefully back through the rob startup procedure. Got to tell you people IT'S ALIVE! IT'S ALIVE! MAKING NOISE! OH YEAH!

Now, I've only plugged in with the two power tubes in and still with the light bulb limiter. It didn't sound good but it sounded fine. Pin voltages all good except I don't have ANY voltage pin 3 power tubes where my sheet says I'm looking for 11 volts. Im going to try to stop myself removing the light bulb limiter until one of you kind people reply to me... please don't leave me too long!
Pin 3 is the cathode… no voltage there would be a very bad thing!
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chaliapin
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Re: new build 36lite with vvr

Post by chaliapin »

It was a bad thing...

Where does the voltage at the cathode pin come from? There wouldn't be anything there with no tube in the socket right? I seem to have am intermittent short/ problem in the power section, back to the bulb limiter, with a power tube in place the light dims after the standby is switched on but then slowly brightens again...
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