Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

New 5e3 kit build

Discussion in 'Shock Brother's DIY Amps' started by Romartin, Oct 16, 2017.

  1. Romartin

    Romartin TDPRI Member

    Age:
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    Aug 7, 2017
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    Yeah I think I may have to experiment a little with the cathode resistor. I’ve wandered about changing the dropping resistor because my b+1 is a little high. Love this pic of the band!
     

  2. Southpaw Tele

    Southpaw Tele Tele-Afflicted

    Age:
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    Jun 30, 2008
    The Golden State
    I love the left handed guitarist! Well, not him, per se...I love the fact he's left handed...er...continue.
     

  3. Romartin

    Romartin TDPRI Member

    Age:
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    There is nothing Funny going on when I play through it. I measured pin 5 on v3/4 and it is reading 0.01 volts. What’s interesting is that when I changed to the 300ohm resistor, my B+ voltages increased. What would cause this increase?

    With the 300ohm(measures 293)resistor:

    V3/4
    Pin 3: 380
    Pin 4: 338
    Pin 8: 23.1

    B+1: 387
    B+2: 339
    B+3: 247

    With the 250ohm resistor:

    V3/4
    Pin 3: 368
    Pin 4:327
    Pin8: 21.2

    B+1: 375
    B+2: 326
    B+3: 239
     

  4. tombob

    tombob Tele-Meister

    Age:
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    Jun 25, 2010
    Sonora, TX
    380v plate voltage is well within range for 6V6s but seems high for a tweed amp. A little bigger dropping resistor might be a good idea, from what I always understood a 5e3 normally runs around 360v/320v on pins 3/4 of the output tubes.
     

  5. D'tar

    D'tar Tele-Afflicted

    Jan 11, 2013
    WNY
    With those numbers I would stick with the 250r.
    The 300r is running a little cool for cathode bias. Really cool if using jj's 6v6s

    As bias current decreases plate voltage will increase and vise versa, this is normal.
     

  6. tombob

    tombob Tele-Meister

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    I looked at the bias calculator on Webers website and it shows 14w dissipation with those numbers too. I'm fairly sure the new Tung-Sols are 12w tubes, JJs and EHs are 14 watts but that's the only two 6v6s I know of for sure that are.
    You can always set the amp where you can see the tubes and turn off all the lights you can then play through for 30 minutes to an hour and if you don't see any glowing spots (RED) on the plates you can be sure it won't really hurt anything (other than maybe your tubes not being quite as long lived as ones run on the cold side)
     

  7. Romartin

    Romartin TDPRI Member

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    USA
    What’s interesting is that when i used the output transformer resistance method to measure plate current, I’m getting only 33mA on each tube, which puts it at 98% dissipation.
     

  8. D'tar

    D'tar Tele-Afflicted

    Jan 11, 2013
    WNY
    You're right, I missed something on the calculation, disregard my previous comment.

    Imo.. A NOS 5y3 and 300R should get you where you want to be. If your using the jj5y3 youll be able to shed a few vdc with nos rectifier
     
    Last edited: Dec 3, 2017
    King Fan likes this.

  9. tombob

    tombob Tele-Meister

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    Sonora, TX
    I've heard the OT shunt method of biasing is more accurate since you're getting the actual plate current and not just voltage so I would bet 98% is a lot closer. I would have thought if you're at 116% you would start to see redplating in 5-10 minutes.
    This reinforces the decision I have made to order a bias probe along with the 5e3 kit I'm about to order :) they measure the plate current too.
     

  10. clintj

    clintj Friend of Leo's

    Apr 4, 2015
    Idaho
    The cathode voltage calc relies on a known percentage of screen current to give a number. The transformer voltage drop or the shunt methods *shudder* are more accurate.
     

  11. tombob

    tombob Tele-Meister

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    Sonora, TX
    I've been thinking I might pick up a pair of Russian 6p3p tubes to try in my 5e3 build. I've used the 6p3p-E coin base version in several amps and they sound great. I've read the "non E" version is only reliable up to about 400 volts but that's good for this use. It seems like the 6p3p is a lower output 6L6 type tube, maybe even a little more so than the 5881. There only about $20 for a matched pair so that's a reasonable enough price for a experiment.
     

  12. Romartin

    Romartin TDPRI Member

    Age:
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    Aug 7, 2017
    USA
    I’m not too familiar with that tube. Are you saying that it can handle a higher wattage than the 6v6?
     

  13. tombob

    tombob Tele-Meister

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    Romartin they're like a 6L6, they sell them as a equivelent to 6L6s. The
    6p3p-E is just like a 5881 and they're really good tubes. I think the "-E" is a Russian abbreviation meaning they're heavy duty. From what I've read the ones without the E are closer to a 6L6GA which is a 19w tube. I've never had any of the 6p3p tubes but I thought for the price they might be fun to experiment with, some people seem to really like their sound. I know they will change your output impedence like any 6l6 though, if you have only a 8-ohm (with 6v6) tap on the OT it will make it run at 4-ohms.
    I also see these listed as 6p3s, I think they are both kind of guesses at what the Russian letter after the 3 on the original boxes translates to.
     
    Last edited: Dec 4, 2017

  14. tombob

    tombob Tele-Meister

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    Jun 25, 2010
    Sonora, TX
    I'm ready to order a 5e3 kit now. I got to take out my 5f6a 2x12 and crank it up a little. I'm very satisfied with how it performed. It had great compression and sustain, I couldn't be happier. I wanted be sure I didn't want to tweak anything else before I started another build. I can't see any way to make my Bassman suit me any better. I think I've read about everything around on 5e3 builds anyway so I'm ready to put it to use.
     

  15. Wyatt

    Wyatt Tele-Holic

    806
    Nov 3, 2004
    The 6n3c-E tube (these characters should be Cyrillic, but the forum software blocks Russian characters) is a Russian tube that roughly translates to the 6s3p-e (latin), this is the same tube as Sovtek 5881WXT. It's a full-blown 6L6 tube requiring more filament current and a different (optimal) plate-to-plate load than a 6V6GT. There are lower-power, less-robust 6n3c and a higher-power, more-robust 6n3n-E versions, the -E version is better suited for guitar amp voltages and abuse.

    The 6P3P is a Chinese tube which is listed as the equivalent of a 6L6GB/6n3c.
     
    Last edited: Dec 5, 2017
    King Fan likes this.

  16. Wyatt

    Wyatt Tele-Holic

    806
    Nov 3, 2004
    Tubes often don't visually redplate until they are past 150%. And in cathode-bias amps, the dissipation will decrease once the signal is applied to the grid, as opposed to fixed bias where the dissipation will increase.
     

  17. tombob

    tombob Tele-Meister

    Age:
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    Jun 25, 2010
    Sonora, TX
    I've used the -E version of the those tubes in several amps and they are excellent tubes. The "non -E" versions are dirt cheap but I've never really trusted them to run in a amp made for 6L6s that run 470 to 500 volts on the plates. I'm thinking about trying them in a 5e3 where they won't run more than 380 to 400 volts on the plates and bias them to about 16 watts at idle. I've found some of the non -E tubes as cheap as $14 a pair so if they don't last long at those voltages or I just don't like them for any reason it's not a big lose.
     

  18. tombob

    tombob Tele-Meister

    Age:
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    Sonora, TX
    Well I did it now... I pulled the trigger on a 5e3 kit so in a couple of weeks I'll be starting my very own Deluxe build! While I am waiting to get it I'm going sit down and decide what mods I do want (I'm not planning on doing anything to far out, a NFB switch, maybe a internal jumper switch between channels and another small tweak or two) and I'm going to draw a new layout with the mods I want drawn in so I don't have to back up and move anything I've soldered to do any of them.
     

  19. D'tar

    D'tar Tele-Afflicted

    Jan 11, 2013
    WNY
    What kit @tombob, Ive been noticing that Dave @ boothill has his kits pretty dialed in as far as hitting desired voltages with components and transformers. Ive not used any but they seem well thought out.
     

  20. tombob

    tombob Tele-Meister

    Age:
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    Jun 25, 2010
    Sonora, TX
    I've heard a lot of good things about the Boot Hill kits too but I ordered one from Mable Audio. They are the people that make the kits Weber sells and the ones they sell are identical to the Weber kits but about 1/3 the price. The 5e3 kit with transformers, tubes and all (except cab and speakers, although they sell a tweed deluxe cab without a speaker for $110) was $220. The 5f6a kit is $308, JTM-45 kit is $358, 5f1 kit is $150 and 18w TMB or 18w tremolo is $250. They're very good kits with carbon comp resistors, "mustard" style caps, large transformers and the tweed amps have steel chassis with good chrome. They come with a mix of Russian and Chinese tubes but I paid a few bucks to upgrade the Shuguang 12ax7 PI and 6v6s to Russian EH 6v6 and JJ 12ax7, they already come with a EH 12ay7 and most come with JJ rectifiers.
     
    D'tar likes this.

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