The Amp Garage

I just made a Bassman 5F6-A Jr. with 2xEL90/6AQ5 tubes. With them you get some 10 W output power. I also made one mini Express with a 2xECL86 power amp giving some 10-12 W. If power amp is very small, you cannot get much useable clean headroom out of it. I made also one amp with 2x6AK6 tubes which g...

As I earlier mentioned, I made a 250-300 W tube bass head with 4xKT-120 tubes. They sound pretty closely to KT88/6550. I made amp with UL and OT primary appr. 1 kohm. KT-120 is a pretty new tube but takes less space in chassis than 6x6550 etc.

I have made different tube bass amps with 100 w, 200 W and 250-300 w output power categories. The newest one Bluetone Ace of Bass is now two weeks old. It`s power amp is based on 4xKT-120 tubes which give some 250-300 W power depending on distortion level etc. Power stage is ultra linear and pretty ...

:) I am happy to see a nice and clean amp inside. It must be same also soundwise. I am aware of AX84000 4-0-0 project. I made one Firefly with a 12AU7 power stage and was not so impressed of triode sound in power stage. That project went to recycling. I am now wondering if one 6SN7 is a better alter...

Thanks RJ. I already have one Lil Devil by Dana with subminiature tubes, but as a tube amp builder (www.bluetone.fi) I am always seeking something new to my customers. I have installed several VVR systems to smaller and bigger tube amps with success and tried all combinations with power scaling them...

Dana! I think that a pair of 6AK6 tubes will give some 4-5 W power, not 10 W like a pair of 6AQ5/EL90 tubes. I am interested in to hear if there is a better sounding alternative to 6AK6 tube giving maximum 5-6 W output power in push pull. Harry

I think that a PPIMV can prevent driving power tubes too hard when using a normal 12AX7 PI. My aim is to get as much as possible of the original Express sound where the biggest part of it comes from PI PA. I know that those tiny tubes are not a pair of EL34, but I think that I will try it anyhow. Ha...

I have tried those tubes, but I am now seeking a real pentode tube sound with reasonable sound pressure. I made also one amp with 12AT7 powerstage, but I did not like the sound. I have built almost sixty tube amps by now but never found a killer sounding small one. Harry

I have been thinking a low wattage Express style tubeamp for home playing purposes (1-4 W). It came to mind that maybe a 2x6AK6 power amp could be a solution for that. The idea is to use Express preamp in it. I already have one Lil Devil by Dana Hall, but I would like now to build an amp with tubes ...

:) I have mated different preamps with different poweramps with good results without knowing what the results will be. If you want a lightweight Twin, go a Super Reverb way and do it with a pair of 6L6GT tubes. It will give you 40-50 W depending on power suppply etc. You can always use any preamp to...

:D If you are after power tube distortion, you can build a little bigger tube amp and add a VVR (Variable Voltage Regulator/Reducer) to it. VVR is pretty simple to add to a cathode biased amp. If you do not want to build it yourself, you can buy a VVR kit from Dana Hall alias UR12 here in forum. I h...

Thanks! I was assuming that it would be something like that but I want to hear other people opinions. I will study that method and try it to my three channel project. Harry

:) Hi! I do not want to hijack this thread but I have similar problem with three channel tube preamp. I already have a logic controller to steer Vactrols or relays for three channels. I have normally used realys for channel switching but now I am intenting to go Vactrol way. My problem is how those ...

Be warned: 300V will be very tough on the screens if you intend to drive the tubes into saturation. I suggest you drop the PA voltage to 200V...250V with a string of 5W zeners (max 20V each) That'll give you 4W+ and is still earache loud when distorted. 125B/125C will offer more impedance options a...

:) I do not know how tight you have with money, but to my mind a better OT is one key to a good sounding tube amp. If the price difference is not too big, I would use 1609. I have used 125 in some of my projects and if I remember right, I got rid of that pretty soon. Despite guitar does not need any...