Right, so I've had this old Peavey Century 200 (4ohm) head sitting around for AGES, finally the other day I decided to give it some company by purchasing a TC Electronic 2x10 (8ohm) cab.
Because the Peavy is 6,000 years old and the cab is pretty modern, they both have different connection plugs (Peavey is standard 6.5mm jack output while the cab is Speakon input).
So I buy the right cable to connect them, turn on the power and everything seems ok. A short while later however I start getting this almighty thudding sound, like a heartbeat on steroids. It doesn't matter which dials I turn on the amp, even with everything dialled off, I still get the thudding sound. I look at the speakers and they're about to jump out of the cab.
Here's the weird part though, when I tilt the head 45 degrees, the thudding stops completely and everything functions as it should. I should also mention there is quite a lot of heat, I'm sensing this is a bad thing as I've never had an amp kick out so much heat.
I'm hoping someone can help me understand what's going on before I ultimately burn down my house.
70s Dynacord Eminent II amplifier. This is a valve powered amplifier originally intended for PA use, using a pair of EL34 run at high voltages for a rated output of 80 watts. In stock form the amp had a four channel transistor preamp, and was built to be very clean and linear sounding. The perspex front panel has green lights behind it, so it's quite stylish in a kitschy way!
I have modified the amp by removing two of the transistor preamp channels and building a preamp based on a late 60s Ampeg B15n using a 6sl7 valve. This is the four black controls on the right of the front panel. I used a high voltage FET stage to match the output and impedance requirements of the 6sl7 preamp to the power amp section of the Dynacord, but the signal path for this bypasses all of the original transistor preamp circuitry. I have also rebuilt the power amp with new filter capacitors and a new pair of JJ E34L valves, and set the bias to suit them. The two original input channels and their master volume and EQ are still functional too.
With the Ampeg style preamp, it provides a very pleasing classic bass sound, and would be a good addition to a retro-minded studio or for moderate volume live use. It doesn't provide heavily overdriven sounds, but with the preamp gain turned up it does a great subtle breakup that thickens up the sound nicely, and it also has a nice range of clean bass tones. It's quiet in terms of background noise too.
It's relatively compact for a valve head, and comes with a well used but useful ABS flight case to carry it in. It has impedance selectors on the back panel to run 4, 8 or 16 ohm cabs.
Cambridge A1 amp. Bought many years ago. Perfect working order and great condition for age. Plenty of connectivity and this one has a built in phono stage.
Happy to ship. Likely to cost and extra 5 to 10 quid If u need me to post. Can confirm exact costs if interested. Collection fine too.
Gathering dust under the bed and needs to used.
Cambridge Azur 350a hifi amp. Great amp and sound. Plenty of connection options. Mint condition. Needs pre amp to play vinyl. Shame for it to be sat under the bed. Can ship as I have packaging but not got a quote. Between 5 and 10 quid I expect.