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Blues Custom Mods

#1 User is offline   PapaMidnite 

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Posted 12 December 2008 - 01:55 PM

If you think this amp is too bright sounding try this mod .Open er up find C6 cap and cut .Pull it back slightly. Now fire it up and listen to the difference.If that is not enough Cut C5 [.This was enough for me ].Again not enough C10 [.have not gone here yet .] The brightness is gone the EQ way more tweak-able .I am Jumping between Tung-sol 5881's and a THD yellow jacket with el84's that's right 84's with these this amp cooks .Also Weber speaker diffusers and for God sake put it on an amp stand .This is a jaw dropping experience .This is how this amp is supposed to sound

#2 User is offline   MikeRom 

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Posted 13 December 2008 - 03:03 AM

I definitly agree with you about the amp stand. Got mine sitting on top of a couple milk crates. Makes quite a difference.

I haven't found it to be too bright though but I'm sure it could use some tweeks and better components.

#3 User is offline   PapaMidnite 

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Posted 13 December 2008 - 03:32 AM

Definitly do the cap cut mod .It's amazing how much better it sounds .I got the idea after seeing and hearing it done to a Valve jr .I don't know why they make amps so bright these days

#4 User is offline   PapaMidnite 

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Posted 14 December 2008 - 05:32 AM

Going to do more mods today. This is for an EL34 tube swap.Should be correct.First Ground tube pins #1 Then replace Resistors R45 &R46 With 1K /5Watt .Then R42 & R43 With 5.6 - 1/2 watt I should now be able to switch between EL34's and 6L6's .I have been wanting to try this for awhile any comments??

#5 User is offline   ebb 

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Posted 14 December 2008 - 06:38 AM

You're a pioneer in this area Papa, in my time here, this is the first BC30 mod thread that I've seen.

Keep us posted=d>

#6 User is offline   arnenym 

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Posted 15 December 2008 - 12:46 PM

Anybody knows where i can find a schematic on these amp?I want to see if i could do a good harp amp out of it.
You say it's too bright to you guitarists and then its probably awful to harp.:-({|= But thats a real challenge](*,)

#7 User is offline   PapaMidnite 

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Posted 15 December 2008 - 05:27 PM

http://www.ppwatt.co..._VER01_DPPT.pdf This is where I found mine .I play some harp through this amp it's so/so. You would be betteroff playing through a Mic'ed 5 watt amp.I'll try it with the EL84's and let you know

#8 User is offline   spaaarky21 

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Posted 16 December 2008 - 05:01 PM

Quote

http://www.ppwatt.co..._VER01_DPPT.pdf This is where I found mine .I play some harp through this amp it's so/so. You would be betteroff playing through a Mic'ed 5 watt amp.I'll try it with the EL84's and let you know


I was wondering about mods a while back and was looking for schematics. Couldn't find any at the time. Gibson/Epiphone actually has schematics on their site but not for all of their amps. Go figure. Are these accurate?

And does anyone know if there are different versions of this amp? Some reviews I've seen online seem to say BC30's bought more recently have a slightly different sound and come with different stock tubes. Anyone?

#9 User is offline   PapaMidnite 

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Posted 17 December 2008 - 10:26 AM

Yes the schematic is accurate.So are the mods.Although tubes will make some difference it's the other mods that do the trick .I'm just waiting for the 1K resistors to come in then onto the El34 mod

#10 User is offline   fenrirlupus 

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Posted 22 December 2008 - 04:25 PM

Posted Image

?? mod: make it more rectangular

#11 User is offline   spaaarky21 

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Posted 22 December 2008 - 05:21 PM

Quote

Posted Image

?? mod: make it more rectangular


Interesting. What is that picture from?

#12 User is offline   PapaMidnite 

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Posted 23 December 2008 - 03:06 AM

Quote


Interesting. What is that picture from?
I noticed the front of the amp is different

#13 User is offline   wiggy 

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Posted 23 December 2008 - 09:00 AM

Quote


I was wondering about mods a while back and was looking for schematics. Couldn't find any at the time. Gibson/Epiphone actually has schematics on their site but not for all of their amps. Go figure. Are these accurate?

And does anyone know if there are different versions of this amp? Some reviews I've seen online seem to say BC30's bought more recently have a slightly different sound and come with different stock tubes. Anyone?


The later ones come with Sovtek 6L6's rather than 5881's. I haven't heard one of the earlier ones but there certainly wasn't the 'ice pickiness' in the tone that people remarked on when I got mine so poss the vale change made a difference.

Dumping the Sovteks and the Chinese Rectifier for some vintage valves certainly sorted the tone out with mine. I'm on the hunt for some vintage ECC83's at a sensible price now to complete the package.
My current Setup:
Genevieve - My Epi Les Paul Standard in Natural fitted with BB Pros
Dot Studio in faded cherry with GFS Mean 90 in neck and Gibson 57 Classic in bridge.
Home built 52 style tele with matched custom wound Bare Knuckle 'Yardbirds'
Epi BC30 fitted with NOS '61 RCA Blackplates and a '59 Mullard GZ34
Strat style bitsa affectionately known as the plank
Korean Tanglewood TW400N acoustic
EJ200CE Super Jumbo
AXL Player Bass

Very little talent & big dreams!

http://www.soundclick.com/ianwigg

#14 User is offline   PapaMidnite 

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Posted 23 December 2008 - 05:31 PM

The real difference between 6l6 and 5881's is that the 5881's will break up a little earlier[ imop.] from the testing I have done .But these amps are made on the bright side according to Gibson r&d depart. That's why i clipped some caps To lesson the brightness these amps are made to do .With the next mod I'm working on I will be able to add EL34's for some British flavor .I also tested with EL84's Very articulate Breaks up much sooner for that deep tube drive. But more defined drive. Bass all the way up ,Trem at 12:00 and Mids from 1 to 3:00 depending on the song I would say more of a Vox AC30. Roll back the volume and you definitely get a Marshall tone .I fired up a Fender Bass man for a side by side using a Tele and if you closed your eyes you would be hard pressed to tell the difference

#15 User is offline   fenrirlupus 

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Posted 25 December 2008 - 06:47 AM

Quote


Interesting. What is that picture from?

gibson.com
... something about opening in ginza...

http://www.gibson.co...m%2Din%2DTokyo/

#16 User is offline   MikeRom 

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Posted 02 January 2009 - 07:07 AM

Well you guys got me curious so I brought my bc30 home from where my band reherses and did the c6 mod. I removed one leg from the circuit board instead of clipping it. Thought it would be easier that way in case I ever want to put it back in. Did a smoke test after that but I won't really be able to take it for a test drive until Tuesday.

#17 User is offline   PapaMidnite 

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Posted 02 January 2009 - 07:47 AM

Ok here's a post from another site about EL34 tube swap idea I've been toying with .What do you think ??? An chanOK Tremo, here's the amp specs, straight from Pyotr Belov:

Straight out of the Box BC30 with stock Sovtek 5881 - Line Voltage 120

Sovtek 5881 Plate 23W dissipation + Screen 3W dissipation.

B+ Voltage - 406VDC - Measured from Pin 3 to ground

Plate Voltage - 375VDC Measured from Plate to Cathode

Screen Voltage - 374 VDC Measured Pin 4 to Cathode

Cathode Voltage - 31VDC - Measured from Cathode to ground

Cathode Bias Resistor - 250 Ohm Rated 25W

Cathode Current - 62mA per tube

These specs were at idle.

I spoke with Pyotr on the phone tonight. He seemed to favor the 6L6GC for a replacement output tube, but he said that any 5881/6L6GC should be alright in this amp. While we were on the phone, Pyotr popped in a pair of EL34's and got these numbers: B+ 396v, Plate 367V,
28.5v Cathode voltage, 57mA per tube, Line Voltage 116v.

I'm going to run these numbers by Lord Valve to get his opinion....minus the 6550 recomendation that is...ce of op trans failure?or do you think it will handle it?

#18 User is offline   PapaMidnite 

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Posted 02 January 2009 - 07:54 AM

I think this is what your looking for.http://www.ppwatt.com/files/ppwatt/E...VER01_DPPT.pdf

That'll get it.

Let's do this conservatively. Remove ONE cap, then play and see if it's better (to your ears) or still needs less brightness. If it needs less, remove one more and then re-play. Etc.

First - remove C6.

Second - C5

Third - C10.

#19 User is offline   PapaMidnite 

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Posted 02 January 2009 - 07:55 AM

to answer my own question, it does not appear to be wired to take EL 34. If anyone wants to try that, first off you need to make the following mods:

1. - Hard wire pins 1 and 8 together on the output tube sockets, or better yet, hard wire pins 1 straight to ground.

2. - Change R45, & 46 to 1k/5W.

3. - Change R42, & 43 to 5.6k/1/2 W


With these mods, you can go back and forth between EL34 and 6L6 by just swapping the tubes.

#20 User is offline   PapaMidnite 

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Posted 02 January 2009 - 07:57 AM

Ok this is where i'm at I did the cap mods .Im thinking about the EL34 mod .My Question is can the Output trany handle it?

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