Blues Custom Mods

[jefrs]

Well well look at this thread it has grown a bit .Nice work all of you. Keep on with it and post some sound bits if you can I would love to hear some .I will pass along to the designer Pytor he will get a kick out of this one.

 

Yes, your thread has grown rather well. Thankyou.

 

I've got my amp just about as I like it now, it is very versatile and sounds excellent (even compared to another nicely modified for EL34 (non-MV) BC30 that I know ;-)

I have made some unnecessary mods to it, like it doesn't really need my bright/gain switch gizmo, but the MV, the tone-stack and the "open" mod do work, as do that wretched rectifier and a general tidy of the wiring for noise. The choice of speakers is important too. I might try some other valves like EL34 in it, but it doesn't need to be any louder. I don't plan any more modifications to it, but one day I might tidy up the front panel where I've put the MV in.

 

Please give compliments to Pytor.

[farinaex]

Oh.. one more thing.. if you want to hear what my amp sounds like (before the MV mod at least) go here http://www.myspace.com/operationkinomusic

 

That is my band.. I'm the only guitarist, the BC 30 volume was cranked to about 2-3 o'clock with the EQ settings I mentioned in last post and on class A/B with Clean channel, I'm playing a Strat apart from on 'Hold My Breath' which I used an Explorer.. no pedals (the Big Muff was too noisy to record) so all you are hearing is the tube saturation. The tubes are..

 

Output: 2 x Svetlana Winged C

V1 and 2: JJ ECC83S

V3,4,5: EHX 12AX7 (stock)

Rectifier: Sovtek 5AR4

The amp and guitar sound hot....right on the money good job on the whole thing....

 

gene / farinaex

[Sava]

Regarding the schematic, the Ver001 is out of date, many of the mods indicated here were already made to my BC30 bought in spring 2009.

R3 is 1.5k not 2.2k; C3 is 101 not 471; C5 is 471 not 101; R8 is 1.5k not 2.2k; R15 is 10k not 2.2k;R21 is 1.5k not 2.2k; R23 is 5.6k not 10k; VR7 is 250k not A1M; VR5 is B250k not A1M. There may be others.

C3 is 101, It is okay. But 471 is C5 or C6?

[jefrs]

C3 is 101, It is okay. But 471 is C5 or C6?

 

I was suggesting the schematic does not always show the correct component values fitted to the PCB. Can you read my diagram?

PM me if you need a more legible one.

[bucknasty]

man this amp was driving me nuts. i had mesa boogie tubes put in right before hernia surgery (last week) so i could play w/ a nice tone while i healed, and didn't have to work - you know, instead of the ice pick tone. it didn't work as well as i had hoped - not nearly. i was about ready to trade it in when i could pick it up again. i read all this today and clipped c5 and c6 successfully and put it back together. sounded better, much better, but not what i was looking for yet. i went back in and clipped c3. now we're talking. its like a whole new amp now. i know it not. it sounds really great and the eq knobs actually do stuff. whoa! its like starting all over w/ a brand new toy.

i can't thank you guys enough. i had absolutely 0 prior exerience w/ any of this, but thanks to y'all on this forum its done.

 

special thanks to the original thread maker. john

[PapaMidnite]

ching Another satisfied customer . Who is John ??????????

[altair]

Thanks to the advice you all have given me in my "amplifier advice" thread, I've located a BC30 and put out a bid on it. It's even got the footswitch with it as well, lucky me :)

Anyway, I was wondering, has anyone been able to mod in an effects loop? I did read in this thread that some have looked into it and deemed it a complex mod.

[wiggy]

Thanks to the advice you all have given me in my "amplifier advice" thread, I've located a BC30 and put out a bid on it. It's even got the footswitch with it as well, lucky me :)

Anyway, I was wondering, has anyone been able to mod in an effects loop? I did read in this thread that some have looked into it and deemed it a complex mod.

 

Weber list a valve driven FX loop mod complete with schematic forfitting at a very good price. Was thinking about adding it to mine and asked the very same question but never got a response so I'm guessing no one has tried.

 

FX Loop

 

Schematic

[altair]

Weber list a valve driven FX loop mod complete with schematic forfitting at a very good price. Was thinking about adding it to mine and asked the very same question but never got a response so I'm guessing no one has tried.

 

 

 

Thanks for the link and schematic! I wouldn't be doing it myself, I'd probably get myself killed, but I know a good amp tech in my area. I'll send the stuff to him and ask if it can be done and for how much. Just that no one seems to have tried this mod already, makes me wonder if it's possible at all.

[j_will]

Thanks for the link and schematic! I wouldn't be doing it myself, I'd probably get myself killed, but I know a good amp tech in my area. I'll send the stuff to him and ask if it can be done and for how much. Just that no one seems to have tried this mod already, makes me wonder if it's possible at all.

 

Don't hate me for asking, but am having trouble getting the amp apart. Any tips/advice?

[j_will]

ching Another satisfied customer . Who is John ??????????

Papamidnite, thanks for all the great stuff. Excited to dig into some of the mod suggestions...one problem though: I am having trouble getting the amp apart. I've taken other amps apart but for some reason can't get this sucker open. Any advice?

[mjlewis22]

I assume youve taken all the screws out of the back panel and pulled it down at a 45 degree angle so that the back is open. To remove the chassis do the following

 

1) remove the mains power cable

2) remove the guitar cable from the input

3) remove the speaker cable from the output

4) remove the reverb RCA cables from the underside of the chassis

5) pry off the 4 plastic covers on top of the amp with a small flat blade screwdriver

6) remove the machine screws with a #2 phillips screwdriver

7) grab the HT and OT and gently pull out while lifting up

 

then,

 

8) connect one lead of an alligator clip to the chassis, and the other end to the common of a multimeter. probe the power tube solder joints making sure to leave one hand in your pocket and confirm the meter reads 0V

 

*if you arent sure about this step read back through this thread*

 

9) mod like hell...

[Rock85]

Hey guys!!

 

I have really enjoyed reading this thread the last year or so and wanted to thank everybody for their pioneering spirit. After accidentally finding a BC 30 on eBay about 18 months ago I found it very appealing to the eye so I did some research and found this thread wich made me buy the amp. To my surprise this amp had all the tags still on it and came in the original box!! It truly looked beand new. Guy said he just used it in his living room. After using everything from a Paula to a tele on it, and treble permanently dialed 0 I made the decision to do Papa's mods. Well that decision was made 8 months ago but then our little baby girl popped out and didn't let me get to much of anything anymore. Yesterday I finally did the mods C3 C5 and C6. Having a 2006 model I also changed the two Resistors R 15 and R 21. ......I am ... Well , going nuts on this amp since....!!! 😁I'll be working on trying different tube setups in the weeks to come but as for now... Rock and Roll!!! I do a lot of rhythm in blues country southern rock styles so finding my own style and sound has always been important to me. You guys made me come very close to what I'm looking for. Only other thing ill be doing is looking into some of jefrs mods and see if they appeal or not....Rock on!

[sakis]

hi to everyone and thanks for the info about the amp. it helped me alot.

do we have anything new about an Fx loop? is it possible to use the RCA of the reverb tank?

[wiggy]

Weber produce a valve driven fx loop kit.

 

I asked several months ago if anyone had

 

a:) Tried it

 

b:) Any opinions as to whether it would work with the BC30

 

Got nada response which, taking into account the technical expertise here, pointed me towards the fact that we are looking at uncharted territory.

 

I also posed the question to Weber (supplied the schematic a the same time) and got zero response.

[mjlewis22]

I gutted the bc30 in an emergency to use it as a cab for a different head. When I took out the reverb I noticed that one of the magnet wires had broken and the spring isnt attached, so its fubar. Now I want to put the amp back together.

 

Anyone have a suggestion on a replacement tank that would be an improvement?

[wiggy]

I gutted the bc30 in an emergency to use it as a cab for a different head. When I took out the reverb I noticed that one of the magnet wires had broken and the spring isnt attached, so its fubar. Now I want to put the amp back together.

 

Anyone have a suggestion on a replacement tank that would be an improvement?

 

There was a thread on this some time back - if you do a search you should be able to find it.

[mjlewis22]

Wiggy,

 

Thanks for the reply, I found the indicated thread.

 

The spec reverb is Accutronics 4AB1C1B, which is a short decay model. It seems though that the long decay model 4AB3C1B is more common, so I may replace with that.

[mjlewis22]

I messed up the speaker cable with the two crimp on connectors and the 1/4" plug. The stock model is lamp cord with a molded right angle plug.

 

Does anyone know where to find one of these? I can only seem to find shielded instrument cable, which is difficult to put crimp connectors on.

 

Thanks

[wiggy]

Maplins or similiar or any hifi dealer

 

Any reasonable gauge speaker cable will do the job just fine.

 

 

 

Crimp connectors on one end and solder (preferably) or non solder type 90deg jack (check out George L) on the other

[mjlewis22]

I ended up going with the MOD 4AB3C1D. It was a little cheaper than the accutronics unit, and it had gotten good reviews. I had to replace its plastic mounting grommets with the rubber ones on the stock unit because the plastic ones are taller and the mounting screws wouldn't bite. It took me a few minutes to figure it out but after that it went back together pretty easily.

 

As far as sound goes the reverb is pleasant, but subtle even with the reverb knob cranked. But it does make reverb so that's an improvement. Just wish I could turn it up to about 13.

 

To fix the speaker cable I just cut the molded end off and replaced it with a 90 degree switchcraft plug. Looks good and works well. That plug was easier to install than any other replacement plug I've done. I'm a believer.

 

I was pretty happy with all my testing on channel 1, but when I switched it over to ch2 it sounded terrible. The more I turned up the drive knob and hit a chord the more it sounded like sitting on a whoopee cushion.

 

Is it time for a tube change? They have a lot of hours on them...maybe 200 or so. Does it matter that the clean sound pretty good but overdrive is weak and flabby?

 

I did mod this amp a little bit back in 2011, and when I was all done it sounded pretty good, I thought. I suspect it just needs new bottles, so Ill try that first. It isn't my main rig anymore, and I thought of selling it but I just really like it so I wanna fix it.

[mjlewis22]

Word of warning: (not that anyone is paying attn)

 

If your re-verb sounds re-pressed, make sure you didnt wire it backwards. Works much better now.

[Andyroid]

For an effects loop you could try something like this. I haven't tried it yet but I'd expect it to reduce the level sent to the reverb tank a little, also the FX return is quite low impedance so line level FX modules will probably work better than typical stomp box type FX. I'd use shielded cable to link to the pot and sockets on the back of the amp.

 

To increase return level and impedance you could probably use a 2k2 resistor instead of the 1k.

 

 

 

--------------------------------------------------------------

Schematic above is updated to fix a bug in the FX return.

[jefrs]

This is a pretty old thread now but I have just been notified of a reply. Any questions re BC30 mods?

 

1) I changed my ISP and hence email addresses, thus notifications got lost in the aether.

2) What was the Epiphone forum is now a Gibson forum. I lost the linky.

 

Re - Greenbacks. They do not break in but just keep sounding better and better as they age.

 

Re - speaker cable. I tend to use mains twin-flex. Mains twin-flex is often better than fancy hi-fi speaker cable, both electrically and more robust. Do solder the connections on because they need to be low resistance, crimp connections do have a significant contact resistance. They work fine in the car where they belong, and there the contact resistance is insignificant or does not matter - or you have a Mercedes and they solder them to the wire anyway (lederhosen have belts and braces ;)

 

Re - the reverb tank. It is a Belton unit. They bought out Accutronics, They don't come much better than the one that's in it. The Belton site is a mare's nest to figure out the correct part number. There should be a part number stamped into the OEM tank. Get the specification from that. I think it is an 8ohm feed. You need to know orientation, insulation, impedance and output. You can ring changes on length, number of springs and decay time etc. The reverb is also dependent on the send level i.e. you get more reverb as you crank it up (becomes more obvious with an MV added). Also note that if you play live and loud - turn the reverb off and let the room do it or it all turns to mush.

[longdog]

Hi guys, thanks for posting all the info on modding the BC30, i've had mine from new, around 6 years now, it still has it's original Sovteks inside it and i mainly play a 2000 Les Paul Standard through it. i've just done the C6 cap cut, fired it up and it sounds beautiful! it now has a very rich and warm sound to it, i love it! it does 'fizz' a bit but rolling the guitar volume back a bit cleans it up nicely and it's not really a bad fizz either. The reverb is now not as overwhelming and is more controlable and i can get the volume up a bit more now indoors too. Only down side is the Drive channell has lost it's bottom and mid, it;s all thin and trebbly now. Before it was thick mid, any thoughts on this anyone? Well. thanks again to everyone thats posted in this thread!