new build 36lite with vvr

Double-Bubble! Place for discussing the 36W version...

Moderators: CurtissRobin, colossal, zaphod_phil, Daviedawg, Graydon

Post Reply
chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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?
1 x

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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.
0 x

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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?
0 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

Re: new build 36lite with vvr

Post by Bieworm »

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
1 x
"THIS should be played at high volume..preferably in a residential area"

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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?
0 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

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?
0 x
"THIS should be played at high volume..preferably in a residential area"

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

Re: new build 36lite with vvr

Post by chaliapin »

Is that the red one?
You do not have the required permissions to view the files attached to this post.
0 x

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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.
0 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

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,...
0 x
"THIS should be played at high volume..preferably in a residential area"

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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?
0 x

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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.
0 x

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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!
0 x

User avatar
JMPGuitars
Super Duper Admin
Super Duper Admin
Posts: 3955
Joined: Tue 09/18/12 8:00 pm
Location: South Central, MA
Contact:

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?
1 x
'I installed a skylight in my apartment yesterday... The people who live above me are furious.' - Steven Wright

Modern Ground Schemes
Soldering Technique
B+ Voltage Reduction
Amplifier Tools & Parts Info


Web Design: DolceVittoria.com
Guitars / Amps / Effects: JMPGuitars.com
(anti)Social: Facebook · Instagram
Items for Sale

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

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!
0 x
"THIS should be played at high volume..preferably in a residential area"

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

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...
0 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

Re: new build 36lite with vvr

Post by Bieworm »

chaliapin wrote:
Sat 01/14/23 5:10 am
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...
You did connect your OT red wire to node A on the HT I hope?

Also… the primary connections from wall power to PT is very confusing. Triple check if that’s ok.
ABA31896-C673-4BB4-9E07-69236D6F460C.jpeg
You do not have the required permissions to view the files attached to this post.
0 x
"THIS should be played at high volume..preferably in a residential area"

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

Re: new build 36lite with vvr

Post by chaliapin »

Thanks bieworm yes, red wire in the correct position. The first diagram you've drawn is the correct 240v hookup for the PT, but what's the second?
0 x

User avatar
Bieworm
Verbose Moderator
Verbose Moderator
Posts: 2287
Joined: Mon 02/10/20 8:24 am
Location: Belgium

Re: new build 36lite with vvr

Post by Bieworm »

Both for PT’s. One for a 0-240V prim and one for a 0-120 / 0-120 universal US/EU hammond
0 x
"THIS should be played at high volume..preferably in a residential area"

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

Re: new build 36lite with vvr

Post by chaliapin »

So blue live, white neutral, the other way round from the handwriting on the Danbury sheet I posted a few posts back. Assuming you're right then I connected it back to front, I'll take a look at it tomorrow. Thankyou do much ,
Mike
1 x

chaliapin
Occasional poster
Occasional poster
Posts: 301
Joined: Tue 03/05/13 5:28 pm

Re: new build 36lite with vvr

Post by chaliapin »

It doesn't seem to matter the polarity of the pt mains connections which is maybe why I have contradictory information. Either way it's giving 290 at the rectifier, 4.5 rectifier heater and 6 at the heater circuit. All following voltages are WITHOUT light bulb limiter, pre amp tubes installed, rectifier installed, NO power tubes installed, power and standby ON. No speaker connected.

V1
P1 166v
P3 1.3v
P6 166v
P8 1.3v

V2
P1 240v
P2 40v
P3 85v
P6 247v
P7 42v
P8 85v

V3-6 no valves installed

P3 0v
P7 400v
P9 390v

Voltage at points
A 398
B 388
C 330

To my uninformed way of thinking nothing seems way off here. But bad things happen when I install 2 power tubes and flick the standby. Gradually increasing hum (volume on zero) power tubes getting bright and hot after a few seconds, then I turn the standby off again before something goes bang...
You do not have the required permissions to view the files attached to this post.
0 x

Post Reply