New amp, Bedrock 651 50w 1/12 combo

[212Mavguy]

I saw a screaming deal on eBay and could not resist the GAS reflex...two channels, reverb, 4 el84's, 3 12ax7's, 50 watts class AB. Bedrock amps were made for a few years by musicians in the Boston area. For a short period of time they were used by Aerosmith. They are typified by using oversized transformers, using printed circuit board design in this model, very high quality pots, they have a reputation for excellent tones. The one I am getting was used less than 50 hours for the 13 years the owner had it in a studio. The only flies in the ointment are shared tone controls between the two channels and the lack of a footswitch.

 

...ordered a new footswitch from the Switch Doctor on eBay. The amp itself arrived yesterday and all was not well...at first fireup it immediately began making some hugely loud static-y noises like it was going to blow up, so I put it on standby and turned the volume down. The amp had been rarely used in the 13 years the previous owner had it...maybe 50 hours total, now with the volume down I tried it again after checking all tubes for proper seating in their sockets, the noise cleared up after a bit and I started to play through it, everything seemed normal except there was no reverb...so I decided a teardown was in order. What I found was pretty interesting...

 

There were three dead pill bugs covered in spider webbing rolling around freely on top of the printed circuit board! It needed debugging in the truest sense of the word! So I turned the amp upside down and shook the little buggers out, and blew some of my personal hot air from my lungs in order to hopefully remove any other stowaways and what I hoped would be any dust out from under the PCB, set the chassis down and decided to remove the reverb tank next...

 

In it I found two multi stranded wires that had broken off at the solder joints on the send side! So I used some solder removal braid to get the excess solder off the tabs and expose a hole in each, stripped a small bit off each wire and resoldered them. Put the whole thing back together and it ROARED!

 

Bedrock used transformers routinely that were double the required spec for power and output, so the amp was quite capable of getting very, very loud, "Mesa Boogie" loud! It had what appeared to be an Eminence ceramic speaker with the Bedrock name on the magnet sticker rated for 100 watts. The tones were awesome, tight, and the switchable for bypass effects loop had a volume knob for both send and recieve sides, they added a huge amount of easily adjustable gain to both channels as an added benefit, the sound that came out with that gain boost added from the loop was all about 80's and 90's rock, enough gain for metal tones, sustain for days, I was astounded how such great tones could come out of an amp that had sovtek 12ax7's and sovtek el84's. The clean tone was warm and full with no flab and would work just fine for a jazzbox as well as making a strat sound warm and fat. You definitely hear the guitar, new or old strings you can easily tell, not the amp imposing itself and masking what was put into it.

 

I think that despite the way oversized iron that the whole thing weighed maybe 30-35 pounds, so I now have a relatively lightweight grab and go amp that can keep up with any band's stage volume and then some as well as work perfectly in a quiet room thanks to a well designed master volume circuit, gain settings are well preserved at low volumes for the dirty channel. Again, the tones were simply awesome, and the shared eq turned out to not be a problem at all. There is a bias pot and hum balance pot on the PCB. Next step is to use a bias tool and determine what setting the stock sovtek power tubes use and roll some vintage Mullards, RFT, JAN Sylvanias, and 6p14p-ev Russian mil stock to see what will sound the best and also to test the phase inverter for matched triodes and look for some stuff out of my huge vintage old stock stash for the preamp. This is going to be a really fun, rewarding project! And yes, I'm going to get a cover for that amp! Any other Bedrock users out there?

[fxdx99]

Nice new amp report, Mav. I've not heard of Bedrock before, sounds like a cool local boutique amp. I had a Mesa Rocket44 that sounds similar in layout and it was a really useable amp. Loud, tho, like you refer to the Bedrock. And heavy - mid 30s in weight for yours is really light so a great gigging combo. Congrats on a good score!

[TheRecordFable]

Might dig this...http://pub19.bravenet.com/forum/static/show.php?usernum=1582348049&frmid=93&msgid=0

 

This to...http://bedrock27.tripod.com/bedrockamp/id9.html

 

Nice amp CONGRATS!

[iim7v7im7]

The guy that designed that amp is Brad Jetter Brad's Bio. The now has a pedal company called Jettergear. If you have questions about it you could try e-mailing him at his new company.

[212Mavguy]

I went to his site. it's inspiring to read his words. I love it when someone is not willing to follow the herd and stays the course in order to find his grail!

[212Mavguy]

An update...

 

The Switch Doctor footswitch arrived, looks to be about as durable as a Mesa footswitch and worked perfectly.

 

I just finished the retube/revoicing last night, used a two socket bias tool to measure plate current draw, had ten VOS Mullard el84's, a bunch of RFT's, and also a bunch of Sylvania's to choose from. Settled on a quad of Mullards, they worked at the same bias setting the Sovteks were using. With them in I was shocked at both the detailed clarity and harmonic content at the same time. That amp is VERY tight and punchy on the clean channel, also very tight dirty, I had all 3 positions in the preamp filled with Euro 12ax7's, v1 Siemens shortplate, v2 Mullard shortplate, PI was Amperex BB shortplate. Decided that three vintage Philips family shortplates in a row was causing too much of the punchy big bottom/mids, so I yanked the Mullard out of v2, stuck the Siemens in there, and put a Telefunken ribbed plate 12ax7 in v1, more compression/sustain, very articulate upper mids and top end , great control over harmonics in the dirty, does the violin sustain thang at higher gain like very few can. Now it's just right. I named that amp "Bamm-Bamm!" Quite appropriate for the sound and the Bedrock brand as well!

 

Same type of thing as my friend's 1/12 Mesa Maverick, big sound in a small box, 4 el84's, but the Bedrock weighs a lot less, smaller in size, possibly louder, trannys are bigger, particularly the OT. Mav is more liquid and smooth, gots blues tones to die for out the ass, the Bedrock has little blues tone in it's soul, but it rocks with the very best of the 80's-90's. Has enough gain for metal, can do the mid scoop thang VERY well too.

 

Might run a cable from the slave out of my 2/12 Mav into the BR's fx return for giggles sometime, the Mav preamp has separate tone controls for each channel, Bamm-Bamm's are shared. Mav preamp is very smooth and liquid-y compared to the BR, and a better reverb. BR has separate pots for FX loop in and out, they offer a huge boost to both preamp channels even with no FX plugged in, and there is a bypass switch for that loop as well. It's a small sized grab and go sleeper amp that has no problems keeping up with very loud stage volumes and definitely lives up to the company motto: "The tone that kills."

 

Bamm! Bamm! Bamm!

[kbp810]

Great update, and may I compliment you on what sounds like a great combination of tubes! Sounds sweet!