I did also look at this one that is calibrated but wasn’t sure if it would work with a windows laptop
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Bloody typical, moment I posted that link a recommendation popped up in Amazon
Just forwarded that onto him.
That’s not USB, so you’ll need a mic preamp with phantom power
I have used Kalibrate in the UK for my mini-DSP stuff
they have always been reliable. I suspect that as Chris says that you are not going to find a UM1k secondhand.
https://www.chromapure.co.uk/details.asp?id=375&type=products
The other option for a measurement mic is a behringer ECM8000 usually around £50 second hand - it’s non usb so you will need preamp and phantom power.
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Was that the TV speaker? 
DIY disaster here today. Whilst in process of putting my RAAL tweeters in new cabs I inadvertently placed the deflector pads sideways slanted near the front of the tweeter, the magnetic pins inside the pads decided that they would rather visit the strong magnet behind the tweeter and shot through the protective gauze and past the ribbon - Shredding it. I think new ribbons are available so it is repairable at a cost. I have emailed RAAL. Bollox.
Ouch!
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Oops !
Golly?
Oh fuuuuuck 
Omg!
Bugger.
Anyone have any beyma cp 22 tweeters for sale?
I assume that’s just one channel? 
I find it hard to accept its only one stack and not stereo.
Got the J2 refurb finished yesterday.
Testing underway with sacrificial speakers, albeit it worked faultlessly from first switch-on, which is always a huge relief…
And mostly done -
How it looked on arrival, full of dog hair -
Component values are unchanged aside from bypassing the 15,000uF smoothing caps with 1,500uf, and ditching the NTC thermistor tying system ground to Mains Earth in favour of a 20W/10R thick film bypassed with 0.68uF Y1 class film cap.
What has been changed are ratings - smoothing caps are up from 25VDC to 35VDC and from 85°C to 105°C lifetime ratings.
0.25W Dale metal film resistors have been swapped for 0.5W ANUK Niobium.
3W Panasonic wirewound ceramic swapped for 5W or 12W Mills non-inductive silicone wirewound. All of the power resistors have been stood off the boards as well, since the PCBs are pretty browned by their heat output.
Generic 100V silver mica caps swapped for 500V Charcrofts.
10uF 25V electrolytics swapped for 160V Jantzen MKT films - which despite their compactness had to go under the boards due to lack of space.
All of the connections to Mains Earth are now star-wired back to one Cliff TP6 binding post on the back panel close to the IEC inlet, and I’ve made proper wired connections from each chassis panel, because the anodising was good enough to raise the impedance sky-high in one or two spots.
System ground is also tied back to just one spot on the PSU.
Steel securing bolts for the transformer and bridges have been replaced with brass, and the bridges are now sat on thermal pads. The bridges themselves have been replaced with 400V ON Semi versions - cheap as chips, and ON silicon always seems quieter and more reliable, so might as well… Prolly change them at a later date for discrete soft-recovery diodes.
Internal power wiring is now screened, and soldered connections replaced with screwed terminals for ease of disassembly should it ever need repairs, or more faff…
Generic IEC inlet replaced with a Rhodium-plated screw-down MS-HD one - because I’ve got to use these things somewhere…
The generic Chinese speaker binding posts have been replaced by Cliff Electronics TP6s - godnose why anyone ever uses anything else, these are better than the pricey foo stuff and dirt cheap despite being UK made…
Replaced the 36mm cartridge fuse holder with a 20mm holder - since that’s the size of fuse I have drawerfulls of…
Metal PSU standoffs replaced with rubber antivibration mounts. Because of Reasons.
Painstakingly pried the transformer off its bed of silicone sealant and cleaned all that crap off - it was a great way of securing and quieting the tx, but it’s only 300VA and doesn’t jump on startup or vibrate in use, and I’ll probably get a better one wound at some point. Sat on a a sorbothane pad now in any case. I also added a mu-metal and copper screen around it.
Obviously I left the various JFETs WAY the hell alone.
Most important change of all: nasty, bright blue LEDs replaced with calmer, dimmer green ones.
A lot of this is anal-retentiveness in action - I enjoy it, and it gives me A Happy knowing things are done optimally and will be easier to service and maintain, but chances are I won’t hear a difference with a lot of it.
But there’s no question some of it needed doing: the smoothing caps were down to ~66% of rated values for instance, while the foo resistors are likely major contributors to how much more realistic this thing sounds now: even the most strident of notes are no longer a painful, unmusical stab to the ear, but instead clearly an instrument or voice doing its deliberately-threnodic thing. Bass depth and control has also taken a welcome step-up, and tonal naturalness is clearly improved. It was already a damn good amp with better component quality than appears in some more expensive kit, but a bit of foo in the right places has worked wonders.
TL;DR - I’ve spent £300 to make my amp worth less on the open market, but at least it sounds better and I had fun doing it 
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Love reading upgrade posts when people (pretend to) know what they are doing.
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If I actually knew what I was doing I’d be designing and scratch-building stuff.
As it is, tweaking the already-excellent is the perfect intersection of limited skills and worthwhile results, and is my Happy Place.
Pre-amp next, wherein every single internal plugged-connection has been glued in-place by a designer and builder who does not answer any form of communication…
Wish me luck… 
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