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Post subject: Re: Bassman LTD conversion to PTP
Posted: Fri Aug 30, 2013 1:47 pm
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From your description, I firmly believe you have a wiring problem in the heater wiring and/or the high voltage power supply wiring. Because green wire was used for everything from one side of the board (white from the other), it is impossible to tell what is connected where in your photos. You need to trace every connection to make sure the circuit is complete with no shorts. At this point, that's all I can suggest.

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Post subject: Re: Bassman LTD conversion to PTP
Posted: Wed Sep 04, 2013 12:36 am
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" OP1 2 and rect is because I thought that using the porcelain sockets. "

Are these Made in China porcelain sockets? Sorry, but they are notorious for poor contact issues from the get-go. Try tightening the female receptors, esp if the sockets are the "cinch-type." Clean the tube pins and apply De-oxit GN5 or some such good contact cleaner. If your voltages are still funky --- try moving the tube, ever-so-slightly. And see if the voltage jumps around.

Hope this isn't the issue, or you are going to have to replace them.

Good luck!


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Post subject: Re: Bassman LTD conversion to PTP
Posted: Fri Sep 13, 2013 11:33 pm
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I will definitely replace the sockets with the brown ones that came in the kit. I went through the complete amp build and found that I missed a wire on the backside of the board.. Now she is up and runnin and is super quiet on the hum. Now the question I have for you guys is that of "ground". What is the best way to run my grounds? The issue I have with this amp not is that it's just now as loud as it used to be and it is a bit muffled.. I took it to a local guitar amp tech here in town and he wan some pretty cool tests but found that its only running at about 25w.. This amp as rated at about 40w.. The tone controls all work but seem to only be noticeable at around 7 and up.. The volume controls are very mellow but only gets up there in volume when it's around 8. Is there a break in period that I should be waiting on for this amp to kick in and sound amazing like I have heard others builds sound like?? Or am I missing something completely...

Mike


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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sat Sep 14, 2013 12:45 am
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Have you checked your B+ supply?

You should be seeing something in the neighborhood of 450VDC at pin 3 of each power-tube socket.

Abnormally low plate voltage would definitely account for the low overall volume and the relative ineffectiveness of the tone controls.

Arjay

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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sat Sep 14, 2013 1:40 pm
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The voltage at pin 3 on power tubes read 470vdc
Still I have a issue with the heater pins as they only read 3.9vac
And now for whatever reason it is popping the fuse... Think it's back to the drawing board for my build...


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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sat Sep 14, 2013 2:53 pm
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michaelbpuccio,

Low heater line voltage and popping fuses usually means a short or improper solder point in the twisted-pair heater line daisy chain. With amp off, check the continuity of the line from the PT through the lamp, to all the tubes in the chain.

Watch that area where the lamp and the two 100-ohm lifting resistors reside. There are a couple of grounding points rather close to the twisted heater line pair. Also, be sure that the lamp and its housing's angle plates are well insulated from the chassis.

Good luck!


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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sat Sep 14, 2013 3:00 pm
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BMW2002Ti wrote:
Low heater line voltage and popping fuses usually means a short or improper solder point in the twisted-pair heater line daisy chain. With amp off, check the continuity of the line from the PT through the lamp, to all the tubes in the chain.

Watch that area where the lamp and the two 100-ohm lifting resistors reside. There are a couple of grounding points rather close to the twisted heater line pair. Also, be sure that the lamp and its housing's angle plates are well insulated from the chassis.


+1000

Arjay

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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 2:08 pm
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WOW!!!!!! Thinkin about this as I am sitting here having lunch with my wife knowing exactly what you mean about grounding points being very close in the area of te lamp that is exactly the problem!! I have the circuit running the resistors straight to ground but the daisy chain wires connected to the tubes.. Wow!!! Thanks for pointing this out to me! Haha!! Now my wife just asked " now that your friends have help you solve the issue with MY Bassman does this mean that we are going home now?" Hahaha!! All equipment is "hers" just so you guys know... and she does help me on working on things so i had to tell her no baby we are still on for the show today.. ;-) I will let you guys know how it goes once I get home though..
Pooch


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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 3:49 pm
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EPIC FAIL! Ok there has to be something else wrong.. I checked the resistors and try are connected from the lamp to the chassis ground.. The wires areconnected from the transformer to the pilot lamp tabs then to the tube pins.. Is this correct? I have seen many other builds online and I do not see these resistors in their builds at all.. I am thinking that my power coming in from the wall to the switches is wired incorrectly.. I am not using a grounding switch due to not having the wan to put another hole in the top of the chassis and the cabel supplies has three wires (black, white, and green). So I know it has ground.. The issue I have with the other two wires coming in.. Where exactly do they go when wiring with a standby switch?

Pooch
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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 5:31 pm
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Wiring like the bottom diagram. Black (hot) to fuse. White (neutral) to power transformer.

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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 5:42 pm
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Wow! Ok that's exactly how I do have it wired up.. Black to the fuse and white to the white from the transformer..

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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 5:53 pm
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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 5:59 pm
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I take it back I am using the original Reissue LTD choke and transformers... The power transformer has only one black wire.. I have it going to the right lug of the ON/OFF switch.. The white wire is going to the white wire from the power cable.. Green is mounted to chassis ground.. I'm the ON/OFF switch along with a standby switch.. Perhaps the standby isn't wired correctly?


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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 6:13 pm
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If you followed the re-issue 5F6-A schematic verbatim, those dropping resistors should only be 47Ω each......

Arjay

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Post subject: Re: Bassman LTD conversion to PTP
Posted: Sun Sep 15, 2013 6:23 pm
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Correct! They read 50 ohms a piece..


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