Jansen Bass 75 Head

in terms of features it has few but what it does have a re spot on. there are to channels, each with two inputs. Each channel has a volume, a bass and a treble dial, on the back panel of the amp is a master volume control.
It is of course an all valve amp, it's designed for 7027a valves, but i have sovtek 5881s in it and it sounds superb. It's not exactly versitile, but you get one of these amps when you know what you want.

I'm using a Burns Brian MAy Signature model guitar with this. IT sounds absolutely fantastic, proper vintage overdrive, i run it with an ibanez fat cat distortion pedal with the input turned on full and the distortion level low, so that the hot signal from the pedal distorts the valves as opposed to the pedal doing the distorion. For clean sounds you need to roll back the volume on the guitar if you've got it turned up loud enough to vave the valves ditorting without a pedal in front of it.

I had a slight problem with it just after i bought it, but nothing a trained technitian copuldn't fix, these things are built like the provebial brick outhouse. And yes i would ig without a backup.

If it were stolen i'd get another NZ valve amp, be it another JAnsen bass, or a holden or gunn, depending on availability, it reallly is a fantastic amp. I have a couple of fender amps as well, a super 60 and a performer 1000, and then overdrive blows the other two away. IT can be used for anything, bass, guitar, vocals for practicing, even had an electric violin going through it. Fantastic amp

The JANSEN Bass 75 is a more powerful version of the Bass 50. The circuitry is identical but the 75 should have 7027A valves in it not the 6L6. The amp is a classic used by many lead guitarists in several countries. The two preamp must be ECC83 (12AX7) and the phase splitter/driver tubes must be ECC82. Any variation will cause problems. Especially if the preamp tubes are mixed. A common cathode resistor is used for the second triodes of each tube so one channel will end up not working. Wrong tubes in the driver stages will cause distortion and loss of power. Many other models including the 6/12Reverb, 6/40Twin, 6/35, 6/40, 7/40, 8/35, 8/50, 12/60, and 12/100 were made and some included Tremolo and reverb.
Jansen is still getting a steady stream of these amplifiers for service and repair which reflects their popularity and reliability. Owners often express the pleasure they have from playing through one.

The Bass 75 and Bass 50 have a preset Master Gain on the rear panel.
It should be set so that the amplifier has enough sensitivity to put out full volume with the channel volumes at half to three quarters rotation. This would be for most pickup settings and with the guitar volume at maximum. Mostly, the preset control would be at about 20%.
The amplifier should then have little or no hum and very little hiss. Of course this should be checked for with the guitar volume at minimum or pickup hum will likely be present.

Can't comment here, I'm the guy who has been servicing the amps at JANSEN for years. john@jansen.co.nz I started with Jansen in 1969 until 1972. Rejoined in 1978 and still here. I will pledge to do my best for all JANSEN owners in servicing and repairing all models made between 1959 to 1999.

Firstly I got an 80's US made Kramer Nightswan that sounds and plays top notch. I added a post phase inverter master volume control. It probably would have been better before the phase inverter since it can make the sound a bit flabby when turned down too low. I also built my own cheapo power attenuator, just resistors arranged for 5 levels of attenuation - no inductance, although sounds pretty good, esp on not too much attenuation. This adds huge versatility to my sound allowing me to get cranked sounds at reasonable levels of volume. With a couple of new preamp valves I am almost approaching metal distortion although a bit noisy. Ill have to put my homemade Voodoo Labs Overdrive copy onto a proper PCB to reduce noise and get some better patch cable. Im considering rectifying and regulating the heater voltage to reduce hum. To increase gain I'll eventually copy a Mesa Boogie MK1, Marshall JCM800 or even a 5150 preamp. Firstly though Ill replace the 25 year old power amp valves and two more of the preamp valves. All these mods should be done by January which should push it into solid 9 category.

Classic all valve 75watt amp design made in May 77 in New Zealand. Primarily designed for bass but I use it for guitar after changing a resistor value to increase gain. 2 independent channels with two inputs each (i.e. 4 inputs total). Each channel has bass, treble and volume control. Adjustable 4/8/16 ohm main and extension speaker out. Has an ECC83 for each channel which both feed into two ECC82s followed by dual 7027a's in push pull config. The amp is also designed to take high rated 6L6GCs. Has standby. Unfortunately no master volume control yet (Ill see if I can add one) so I can't get much distortion unless I crank it which with my dual 12" speaker cabinet means you can hear it down the street. Would gig well. Classic amp what youd expect- no FX loop or master vol, but 4 inputs (could do both bass and guitar simultaneously) and dual tone controls (a mid would be nice though) - 7.

My guitar - a cheapo secondhand Strat copy (think it is Jap)- surprisingly very good. Fairly high output single coil pickups, which are prone to noise, and pretty good tone. I like to play classic rock, bluesish rock and metal. Amp goes to 2X12" cab. The amp gives brilliant classic rock and blues/rock distortion sounds when cranked (3/4vol up) - sounds like Voodoo Child or Smoke on the Water. Plays Sabbath metal and some GNR allright but not enough gain for Ozzy, Metallica, Satriani (ECC82s probably get in the way) even with an overdrive pedal (ie not on pedal distortion but full output vol). Fantastic clean sound. Overall very nice except for high distortion and a very little bit of noise.

Bought second hand - I haven't had it long so I wouldn't know. Power tubes are original Sylvanias so I don't think its been serviced a lot but it still goes nicely so Id expect it to be pretty reliable.

Excellent even though Jansen stopped making amps during the 90's and my model is old. A technician faxed me the amp schematic and suggested I change a resistor for guitar usage to increase gain. They also will still service them.

This kills my piddly little Ross RG10 practice amp. Perhaps I could change all preamp tubes to top notch high gain ECC83/12AX7s and whack in a master volume control. However for the incredibly low price about $200US with dual 12" sp. cab. it was a steal. The transformers and sp. cab. would be worth more alone. If someone nicked it I would pick up another bargain NZ made amp.