Newbie BootHill 5E3 build

Supertzar

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Finally got time to replace the bad 220k grid leak resistor and double-check everything. Things looked good so started on Rob's Startup procedure using the light bulb limiter got all the way to connecting the speaker and installing power tubes found light stayed bright after Standby switch on. Removed my V3 power tube and light dimmed, swapped V4 into V3 socket and light dimmed also, believe my original V3 tube is bad. Being a newbie I have no spares off to order new set of tubes from TubeDepot. Week has gone by and tubes are going the wrong way across Tennessee according to USPS, I have free time now so I head to GC and find a Groove Tubes 6v6 set there to use while I wait for my order.

Get them in using light bulb limiter and looks good there, I have sound no redplating so removed the limiter. I have sound but not very loud now I'm scratching my head.

PT Classic Tone 40-18021
OT Hammond 1750E
RCA 5Y3GT
GT 6V6-R
Syl 12AX7
Unk 12AX7

No limiter

Wall - 123.6v
B+ 389.9
B+1 389.9
B+2 340.5
B+3 263.0

V1 unk 12AX&
P1 180.5
P3 1.353
fil 6.66
P6 181.0
P8 1.344

V2 Syl 12AX7
P1 169.3
P3 1.390
fil 6.66
P6 213.1
P7 19.04
P8 50.2

V3 GT 6V6
fil 6.67
P3 382.7
P4 339.1
P8 21.29

V4 GT 6V6
fil 6.69
P3 383.7
P4 340.4
P8 21.32

V5 RCA 5Y3GT
fil 5.22
P3 370.9
P5 370.9

Anything look suspicious I don't see?
I posted pics back in post #19
 

Lowerleftcoast

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I would expect those voltages. The Classic Tone 40-18021 710V CT has a little higher voltages than the Classic Tone 40-18016 660V CT that I have used.

I would put a 12AY7 in V1. YMMV.

Assuming a 250R bias resistor the MPD is ~104% which is fine. How does it sound?
 

Supertzar

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I would expect those voltages. The Classic Tone 40-18021 710V CT has a little higher voltages than the Classic Tone 40-18016 660V CT that I have used.

I would put a 12AY7 in V1. YMMV.

Assuming a 250R bias resistor the MPD is ~104% which is fine. How does it sound?
Not much volume other than that I think it's
pretty good. I have a 12AY7 I can put in V1.
I've tried all 4 inputs still not very loud.
 

Supertzar

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Pop test was good. Changed V1 to 12AY7 voltages a lot closer to typical.
P1 128.1
P3 1.99
P6 129.1
P8 1.988

V2
P1 168.9
P3 1.318
P6 208.1
P7 17.64
P8 44.5

20211023_090125.jpg
 

andrewRneumann

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Where are we at with this amp with a lack of volume?

I’ve been looking at stuff on cathodyne PI’s and that 17Vdc grid voltage depicted on that Weber layout still makes no sense to me. Could anyone explain it?

Could you lift one end of that old (I assume) carbon comp 1.5K on V2B and check its resistance?
 

D'tar

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Whoa, I guess I have to go and study up on cathodynes. I thought the 1.5K bias resistor would put the grid a volt or two below the cathode. Am I missing something obvious?

The 1M grid leak will mess with most meters...
Test at the top of the 56k tail, may look more reasonable
 

Lowerleftcoast

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I’ve been looking at stuff on cathodyne PI’s and that 17Vdc grid voltage depicted on that Weber layout still makes no sense to me. Could anyone explain it?
This might 'splain it...

https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-57-Deluxe-Schematic.pdf

The schematic shows 17.4VAC. That is if there is 100mVAC signal at the input. I am not so sure a DC reading on pin7 means anything worth noting. Of course maybe there is something to it if it is a symptom of the issue we are looking for.
 

andrewRneumann

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This might 'splain it...

https://www.thetubestore.com/lib/thetubestore/schematics/Fender/Fender-57-Deluxe-Schematic.pdf

The schematic shows 17.4VAC. That is if there is 100mVAC signal at the input. I am not so sure a DC reading on pin7 means anything worth noting. Of course maybe there is something to it if it is a symptom of the issue we are looking for.

Wow, I think you may be right about where that number comes from! That is quite a discrepancy. So I’m going to just say that if there is 17Vdc to chassis on P7, then something is wrong. It should be a volt or two less then P8. Would you agree?
 

Lowerleftcoast

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So I’m going to just say that if there is 17Vdc to chassis on P7, then something is wrong. It should be a volt or two less then P8. Would you agree?
I really don't know. Depending on which meter I use, I get weird wild readings when there is AC riding with DC. As D'tar mentioned that reading may be out of place. I would think there would be scratchy pots if there was that much DC there. ?????
 

Supertzar

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I'll have to recheck that voltage reading as my meter was auto range when I was checking so very well could be AC. No scratchy pots. I'll check after work and update.
 

SacDAve

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Do you have a pic of the output jacks? Seems a lot of people have a problem with them.
 




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