18 Watts amp start up issues

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Re: 18 Watts amp start up issues

Post by JMPGuitars »

davemojo wrote:
Thu 04/15/21 6:56 am
So I made a mistake there? shall I cut them off and isolate them with heatshrink instead as you mentioned once?
Keep it simple. Above you have a photo with the orange and blue wires connected to terminals. That's fine, as long as those terminals are not contacting anything else.

Follow your diagram:
tonefactory_18_watt_power_transformer.jpg

The green/yellow, and the yellow wires should be connected to your power amp star ground. If you're not sure what that is, read the modern ground schemes thread in my signature.

White and black wires are your mains connections.

Pink and gray are your heater connections for an EZ81 rectifier.

Green and Green are your heater wires for the rest of the tubes.

Red and Red are your high voltage AC wires going to the rectifier tube to be converted to DC voltage.

If all that is correct, then move on to the next thing and see what is shorting out that shouldn't be.

Use a highlighter to verify that you wired everything correctly, following both the schematic and layout.

Thanks,
Josh
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Re: 18 Watts amp start up issues

Post by davemojo »

Yes thanks just for the sake of being 100% sure I cut the blue and orange from the terminal and isolated them with heatshrink the short remain. Now I am following Josh steps and thanks Bieworm too :-) for his reply
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Re: 18 Watts amp start up issues

Post by davemojo »

Here the checks Josh

1) The green/yellow, and the yellow wires should be connected to your power amp star ground.

This is done correctly I checked, the terminal strip is a 3 lugs one with a jumper connecting together all 3 lugs as per kit instructions

2) White and Black seems correct black goes to main switch and White goes to fuse box.

3) Pink and gray both goes to V6 EZ81 Socket pin 4 pink and pin 5 gray so seems correct too

4) Red and Red are going to rectifier V6 EZ81 pin 1 and pin 7 seems correct too

I attached 2 photos one closely shows the 2 green going to V5 4 and 5

At this point from there there is the daisy chain that I made with black and white wire that connect all the other sockets so the short could be somewhere from this point ahead the white leaves the pin 4 twisted with the black that leaves pin 5 of that V5 socket and they respectively reach the same on V4 pin 4 (white) and pin 5 (black) this is the same down to all the other remaining socket but need to double check if there is solder touching the closets pin
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Re: 18 Watts amp start up issues

Post by Bieworm »

Yes
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Re: 18 Watts amp start up issues

Post by davemojo »

Bieworm wrote:
Thu 04/15/21 8:10 am
Yes
:lol: Ok and now how to proceed? I am rechecking but is getting not so easy but I must get, somehow, to the bottom of this
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Re: 18 Watts amp start up issues

Post by davemojo »

Bieworm wrote:
Thu 04/15/21 8:10 am
Yes
When the limiter bulb light bright up I counted around 15 secs maybe almost 20 secs should dim out maybe after a while or 20 secs is already a lot and should have dim out only after few secs? See I am afraid with the short on that I damage something, maybe is the 20 secs too short time , I am trying to pretend there is no short hehehehe
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Re: 18 Watts amp start up issues

Post by JMPGuitars »

Please read the solder technique thread in my signature, and watch the videos.

Thanks,
Josh
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Re: 18 Watts amp start up issues

Post by davemojo »

JMPGuitars wrote:
Thu 04/15/21 8:34 am
Please read the solder technique thread in my signature, and watch the videos.

Thanks,
Josh
Yes I red all the links on the signature about a week ago I understand more now, but when I read those the amp was already finished so...

Now there might be unclean solder everywhere in the amp on the sockets lugs but I don't really see solder leak's touching other close lugs, what I am trying to say is that at this point don't think the short is caused by a soldering issue but by a possible wrong wiring I am rechecking everything again one by one all connections
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Re: 18 Watts amp start up issues

Post by Bieworm »

davemojo wrote:
Thu 04/15/21 8:17 am
Bieworm wrote:
Thu 04/15/21 8:10 am
Yes
When the limiter bulb light bright up I counted around 15 secs maybe almost 20 secs should dim out maybe after a while or 20 secs is already a lot and should have dim out only after few secs? See I am afraid with the short on that I damage something, maybe is the 20 secs too short time , I am trying to pretend there is no short hehehehe
Is it me or am I missing something? I have no clue why a bulb current limiter should light up when all is well.
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Re: 18 Watts amp start up issues

Post by davemojo »

Bieworm wrote:
Thu 04/15/21 9:20 am
davemojo wrote:
Thu 04/15/21 8:17 am
Bieworm wrote:
Thu 04/15/21 8:10 am
Yes
When the limiter bulb light bright up I counted around 15 secs maybe almost 20 secs should dim out maybe after a while or 20 secs is already a lot and should have dim out only after few secs? See I am afraid with the short on that I damage something, maybe is the 20 secs too short time , I am trying to pretend there is no short hehehehe
Is it me or am I missing something? I have no clue why a bulb current limiter should light up when all is well.
I am not sure if I understand I didn't say all is well, in fact there is a problem, I was just wondering since on YouTube they are sayin it should bright up once you turn on the amp and dim out, but here stays steady bright so yes there is an issue.

I think I found the problem or at least one of them see my next reply
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Re: 18 Watts amp start up issues

Post by Bieworm »

I think Josh is advizing all that non specifically. In general your build is not really in line with how we try to perform our builds. Don't be offended please...I'm only trying to help and hand over my observations.
I think you should study the photos of builds from Josh or Craig... look at the way they run their wiring, twisted and alligned, heatshrink at the connections,... I struggle with that too, but I try to do my best following those examples. It's beneficial for tidy looks, easier troubleshooting and less chance for errors.
I built another amp after my first crappy build with all that in mind. When I kinda succeeded in that I rebuilt the first amp entirely 😀
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Re: 18 Watts amp start up issues

Post by davemojo »

The issue seems on the heater wire when they go down starting from V5

I am not sure if that is an issue but, the layout picture show the white heater together with the green from PT connected to pin 5 and the green with black to pin 4 socket V5 it continuous the same on V4 but when reaches V3 white goes to pin 4-5 and black to pin 9 this is the same all the way down to V1

In reality I inverted the color done the opposite but I don't think this can cause the short since I just inverted the colors but they are connected to the correct lugs all the way to V1 that's all
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Re: 18 Watts amp start up issues

Post by davemojo »

Bieworm wrote:
Thu 04/15/21 9:44 am
I think Josh is advizing all that non specifically. In general your build is not really in line with how we try to perform our builds. Don't be offended please...I'm only trying to help and hand over my observations.
I think you should study the photos of builds from Josh or Craig... look at the way they run their wiring, twisted and alligned, heatshrink at the connections,... I struggle with that too, but I try to do my best following those examples. It's beneficial for tidy looks, easier troubleshooting and less chance for errors.
I built another amp after my first crappy build with all that in mind. When I kinda succeeded in that I rebuilt the first amp entirely 😀
Nope not offended at all, I got it, so what would you suggest here leave it as it is? I have all parts for the same build, follow Josh layout?. The are some differences what chassis should I use on that one since it seems without Tremolo, in other words I cannot give up until I succeeded
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Re: 18 Watts amp start up issues

Post by TriodeLuvr »

This isn't good. None of these connections appear to be properly soldered.

Jack

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Re: 18 Watts amp start up issues

Post by davemojo »

@Josh from JMPGuitars and @Bieworm

I agree to leave this Stewmac build aside I will troubleshoot another time
I think the trouble is at V3 socket there is some **** there with soldering and messy lugs too much solder and the socket may be even ruined. However atm let's leave this behind

I can start the new build, but your Modern schematic, actually seems a lot more clean, easy to follow, easy to understand, actually even simpler over all.

Could you suggest where can I get the right chassis that best suite that build since my one seem not matching it, looks like I could still use it but I would leave some holes since your schematic is using 5 tube sockets, and the knobs are just Volume and Tone all the other knobs for volume treble bass are not needed.

Long story short I need to find the right chassis, can you help? Do I have to build it myself that would be too much :D
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Re: 18 Watts amp start up issues

Post by Bieworm »

While not adviseable it shouldn't be a problem switching heater wires. The filaments aren't polarized. Look at fenders ..they use the same green wires for both sides and they are often switched from tube to tube.

And yes.. if it were me I'd try to make a fresh and clean build..slowly and detailed. And with the acquired experience go back to the first build...
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Re: 18 Watts amp start up issues

Post by Bieworm »

I always buy blank chassis. It's fun to start from scratch.
But if you are not equipped or into metal work it's not adviseable.
Check the chassis offerings at tubetown germany. They have lots of different types at very fair prices.
My last blank was only 17€

Which amp are you going to build? I'll help you look
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Re: 18 Watts amp start up issues

Post by davemojo »

Bieworm wrote:
Thu 04/15/21 10:59 am
I always buy blank chassis. It's fun to start from scratch.
But if you are not equipped or into metal work it's not adviseable.
Check the chassis offerings at tubetown germany. They have lots of different types at very fair prices.
My last blank was only 17€

Which amp are you going to build? I'll help you look
Yes must be this one you got

https://www.tube-town.net/ttstore/tt-ch ... -x-65.html

What about the faceplate this is going to be all custom, drilling and cutting the metal can be done no problem on that, but the faceplate how can I put the gold Marshall style front and rear plate, can that be customized too?
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Re: 18 Watts amp start up issues

Post by davemojo »

Bieworm wrote:
Thu 04/15/21 10:59 am
I always buy blank chassis. It's fun to start from scratch.
But if you are not equipped or into metal work it's not adviseable.
Check the chassis offerings at tubetown germany. They have lots of different types at very fair prices.
My last blank was only 17€

Which amp are you going to build? I'll help you look
I want to build the amp based on Josh schematic
JMPGuitars_18_Watt_Lite_2b_Layout.pdf
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Re: 18 Watts amp start up issues

Post by Bieworm »

davemojo wrote:
Thu 04/15/21 11:07 am
Bieworm wrote:
Thu 04/15/21 10:59 am
I always buy blank chassis. It's fun to start from scratch.
But if you are not equipped or into metal work it's not adviseable.
Check the chassis offerings at tubetown germany. They have lots of different types at very fair prices.
My last blank was only 17€

Which amp are you going to build? I'll help you look
Yes must be this one you got

https://www.tube-town.net/ttstore/tt-ch ... -x-65.html

What about the faceplate this is going to be all custom, drilling and cutting the metal can be done no problem on that, but the faceplate how can I put the gold Marshall style front and rear plate, can that be customized too?
Yes that was the one I used to buy. But they were like 14€ a year ago.
This is the one from my last build. I'm only buying these from now on. But I'm building bigger amps with larger circuits nowadays
https://www.tube-town.net/ttstore/tt-ch ... -x-65.html
This is the finished chassis
20210325_202152.jpg
You can buy custom faceplates there for like 20 -30€.. I make mine myself, but they're prototypes. I'm looking for a 3D printer with lasercut functions... but the prices..aaahhh
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