I've had Niks' 45/100 for almost a month now and I really like the tone.I use my over 30yr. old strat style Ibanez guitar on the neck pup and a fuzz that I keep on all the time,I also jump the channels which gives me a deep rich sound. with a turn of my guitars' volume knob i can go from clean to distortion.It's not a heavy metal amp,it lets your picking technic and dynamics come through.
It's a classic rock amp so that if I want long singing sustain and feedback with my setup I have to turn it it up to about 5 or 6 which I haven't done too often because this amp is loud,I mean very,very loud. I LOVE IT.Nik installed a PPIMV which I use at home but at band rehersals I run it out of circuit because I don't need it and it seems to have a slightly better tone.He also installed an external bias so I can check and set the bias myself with no problems.I have heard it said that when you turn a 45 up the bass gets flabby,I haven't had this problem.I have noticed that when I do turn the volume to about 6 I begin to hear faint ghost notes.I haven't asked Nik about this yet because I wanted to do as much research on it before I bothered him with questions about what if anything can be done about it.
This amp has the volume and tone I've been looking for,this is classic Hendrix.
   As far as cabs go I use a Marshall HW1960b which is a great match for me.
I don't know if the 45 has the same tone as the 45/100 just at a lower volume,but again let me warn you if you thinking about getting this amp.
   It is very,very loud.

 Yeah, I didn't like the scooped mids of the regular 1960b cabs and when I use my fender super reverb to push my HW1960b I don't hear the ghost notes.But like I said earlier it's very faint and at 6 i'm extremely loud. Also if I just run through a single channel at that high volume the ghost notes are even harder to hear.I love the sound the HW1960b gives me with this amp so if it turns out to be the cab then I am going to have to live with it because to y ears they were made for each other..

seeker -
Nice review.
If the ghosting continues, you may want to try/get Nik's opinion on increasing the B+ filtering.
Good Luck

NP, I too wish to learn like you.

Its great that you've contributed to this thread.

I have no idea where B+ is located in any amps, but from what I've gathered, its the voltage supplied to the circuit.

I've a couple of Nik's amps and would like to get the JTM45/100, just that I'm not sure what to pair it with.
And Nik doesn't make 4x12s, so getting a suitable cab and speaker combo here is kinda tough.

Btw Seeker, are you or any amp tech in your area able to measure the RMS and peak output of this beast?

Thanks hywelg,

Btw, I gather that a JTM45/100 B+ should be high, 500V? Or thereabouts, but I see the PT in nik's layout  supplying 360V, noob question, but how did 360V get to 500+? I think this is the plate voltages.

I know after rectifying, you get whatever is put into the rectifier circuit. Albeit peaky and what not which requires filtering.

Yup, they're rated at RMS, but there's a way to calculate the actual output. George from metro did run thru it before. Something about using some meter on the output and sending a sine wave thru the input.

Then doing some calculation.

If you every do get to find out what's wrong, please do let Nik know, he continues to develop and refine his products based on customer feedback. I'm sure he'll want to know what's the problem and help you solve it.

hired hand the highest ma is 40 the lowest 34 on the power tubes.
 I'll try another set of tubes as soon as I can make up a believeable lie,I mean reason to my wife for spending another hundred plus dollars on tubes. I'll also see who sells tubes that are matched..
  I want to add that like I said earlier the ghosting is faint and and unless it gets very annoying it's not a big deal so I'm going to approach this as a teachable moment on amp building and troubleshooting...