Guitar combo rebuild

[chris p]

Thanks to Dale (aka Ha Ja Da) for supplying a 10" Celestion Vintage 60W driver and JLM for their 60W power amp kit, I have totally rebuilt a be!@#$%^& 10" 30W amp into a nice sounding, usable combo.

And by stripping off all the be!@#$%^& badging and stuff, it actually now looks good as well.

The amp build was as per diagram, except that I added a JLM 1:4 tranny wired in from the inputs (secondary) to an XLR (M) socket (primary) to provide a -12db DI out from the combo's input (which is, in practice, my pedalboard output at nominal +4dbu). Nothing particularly difficult about it, but a nice result all the same. It reminded me that DIY needn't be spectacular to be good or useful.

[astrovic]

Nice work, as per usual.

be!@#$%^& really are one of the leading suppliers of chassis and rack cases for DIY projects, aren't they? Shame you have to pull out the packing first - I don't know why they don't use foam or bubble wrap inside rather than circuit boards n stuff.

I imagine that the sound is very clean - how loud does it get? Would it go close to doing a small gig or is it more of a bedroom and rehearsal space beast? Have you tried it with pedals in front? How does it go?

[TimS]

Chris P, how about some pics of your new amp ;-)

[heathen]

Nice work, as per usual.

be!@#$%^& really are one of the leading suppliers of chassis and rack cases for DIY projects, aren't they? Shame you have to pull out the packing first - I don't know why they don't use foam or bubble wrap inside rather than circuit boards n stuff.

Yeah like the hp amp i bought, farout what was i thinking, noisiest piece of crap i ever bought.

[astrovic]

Nice work, as per usual.

be!@#$%^& really are one of the leading suppliers of chassis and rack cases for DIY projects, aren't they? Shame you have to pull out the packing first - I don't know why they don't use foam or bubble wrap inside rather than circuit boards n stuff.

Yeah like the hp amp i bought, farout what was i thinking, noisiest piece of crap i ever bought.

Sorry to digress Chrisp....

But the experience is fresh in my mind - I grabbed Angus' not working ADA8000 off him for $50, thinking that either I've got a A/D/A I can repair, or worse case scenario a $50 chassis for a future project. No downside either way.

Quickly saw that the filter caps on the +- 15V and 17V rails had detonated - replaced them, jumped the burnt out tracks, replaced a few faulty rectifier diodes, and bingo - power supply back to being good as gold. Preamps giving every impression of passing audio. By now I'm thinking "move over Rob and Joe, there's a new badass in town"

Plugged the ADAT ins and outs in....did it work? Hell no....who was I kidding? :)

Next step - bugging Joe Malone to release that A/D kit he's been threatening to make available, and building an actually decent converter into that $50 chassis what I bought ;)

[TimS]

Chris,
I nearly bought it as well, and spoke to a few about repairs..
It would have honestly been cheaper to buy a new one.. good ol' Be&*^$%@$& - they make good throw-away crap sometimes....
Good for you for giving it a go tho..

[astrovic]

Oh, I haven't given up hope just yet...I refuse to let reality get in the way.

[Kurt]

Isn't that just a Samson a/d board with some transformers in front? I can't see how the quality of a/d would be any different to the be!@#$%^& unit.

Next step - bugging Joe Malone to release that A/D kit he's been threatening to make available, and building an actually decent converter into that $50 chassis what I bought ;)

[rob]

well, the A / D in the bigB unit actually isn't that bad.

it is more about the implimentation of the audio paths.

there has been volumes written on DIY forums about modding these. Unfortunately, i haven't seen anyone suggest the mods that it actually needs to make it pretty respectable......they would be tricky to do and probably not worth the effort.

As to using a bigB case as a blank case for a DIY project.....why?? For $70 you can buy a blank case and a least do your worst to make it look unique....and isn't that what DIY is all about?

rob

[astrovic]

Indeed, Rob, you wouldn't buy it to use as an empty case. The primary objective remains to get the unit working...and of course, I've also learned a mountain about digital audio, fault finding and repairing already on this project, and I've only just scratched the surface. So I reckon I'm ahead so far.

But if all else fails, and the unit is a dud...the chassis is still good for something else. Call it recycling :)

[rob]

fair call

and it is encouraging to hear of people getting their hands dirty trying to bring stuff back to life, so big ticks all round

Rob

[chris p]

Chris P, how about some pics of your new amp ;-)

You want pics of be!@#$%^& cabinet????





Only tricky bit was that the vol pot sat right over the toroidal tranny and was picking up Lots'o'Humâ„¢. I used some shielded two core cable (shield going to the pot body and 0V at the PCB) to fix that - could have just moved the pot somewhere else, but layout wise it was nice to keep it there.

I imagine that the sound is very clean - how loud does it get? Would it go close to doing a small gig or is it more of a bedroom and rehearsal space beast? Have you tried it with pedals in front? How does it go?

Clean, yes. Even when loud, its clean. Loud enough for small gig, definately yes, but its also got that DI out for FoH if more watts is needed. I've tried it out just pluggining into it from my guitars, and it has enough grunt to make that workable. I really designed it though to go from my pedalboard (Zoom 9.2tt) which chucks out a +4dbu signal. The amp and Celestion combo provides detail and accuracy combined with a Celestion vintage tone. I was flicking through a few patches on the Zoom and came across a surf guitar setting. I switched my guitars front pickup from humbucking to single coil, and was so inspired by the tone I wrote a new 60's type surf anthem right then and there! I tried out a U2 song, some Clapton, some Santana, it all come out very sweet.

Next step - bugging Joe Malone to release that A/D kit he's been threatening to make available

So far as I know, he never promised it as a kit - it was available as a complete unit - he just doesn't advertise it on his website.

[astrovic]

Thanks for the pics Chris - I was quite interested to see how the heatsinking of the transistors was approached. It looks like you've simply bolted them to the chassis? From following the posts on Joe's forum including your monitors build (nice work BTW), I was curious about how much heatsinking is enough with these fellas.

Makes sense using a multi-FX unit like a zoom etc...essentially as a preamp, hey?

Great stuff and sorry for hijacking your thread...thanks for the comments about Joe's converter, I will probably shoot him an email if I can unlock the mystery of the ADA8000.

[chris p]

Yeah Chris, I just bolted the bridge rectifier and the amp IC with a bit of thermal paste to the chassis, which is nice thick aluminium and has two rows of slat vents either side of my bolt position that will act as fins. I rule-of-thumbed the surface area of the chassis bottom to be about the same as my monitor heatsinks, and on trial it doesn't even begin to melt - to be honest its only just detectably warmer than environment.

Cheers on my monitor build. An classical music friend lent me her CD of the Pieter Wispelwey Bach Cello suites the other week, and I put it on just casually while she was there. As soon as it started playing, she just sat straight up and looked around to see what speakers I was using - she'd never heard it with that clarity before. Joe's amp with the bass adjust tweak and the Jordan full range drivers are a match made in heaven.