Warren Jones

Those measurements are no load. These measurements were taken on my previous version directly from the motor feedback FG both no load and playing Pink Floyd Eclipse. The loaded difference is extremely small 0.008WRMS No load Playing Pink Floyd Eclipse.

Here are a couple of measurements. Level of detailed information is invaluable to improving the bearing on my highly modified inverted bearing SP10. Look how stable the speed vs time plot is. W&F WRMS = 0.000, but more importantly I see PEAK W&F has decreased indicating a much more stable platter. Standard Technics SP10 Modified Inverted Bearing SP10 the next 2

I also use a Shake n Spin which is has the facility to download the data to a spreadsheet and graph stability and speed variation. This functionality is particularly useful for anyone repairing/modifying turntables. The benefit to using a device on the platter is it not only measures W&F but total platter stability. I have used a couple of phone apps (Android) and they IMO are not up to the task I need, all Android version only measure WOW not W&F. These phone apps are fine for anyone looking at a quick verification totally useless for me building my own TT's and bearings.

I tried wall mounting and found it made no difference so I went a different route. My walls vibrated almost as much as the floor (I'm on stumps). My TT now sits on a Minus K but these are around $7-8k before this I built a sprung isolation platform which worked pretty good for under $100.

There is a plinth cutout plan in the service manual. I also have a DXF of the chassis if you have 2D CAD..

It's unlikely that arm is is high mass as it's a copy of the Technics arm. The problem with EM specification is it does not specify which cartridge is used so the spec is totally useless. I would install the EPC205 and use it. The spec on the EPA-100 is 22g with the EPC-205.

The stepdown Tx should have a 3 pin socket with a ROUND earth pin. You should purchase the correct power lead with round earth pin.

Because equipment must be compliant with Australian electrical safety standards. I will work perfectly until the device has a fault it may not trip the breaker and could cause electrocution.

If the Turntable is Class 1 by law it MUST be earthed. Failure to do so will only be a problem if your house burns down or someone get electrocuted. Class 1 is earthed and Class 2 is double insulated, in Aus Class 2 equipment has a Box in a Box symbol on the label. If that symbol is not there the equipment is deemed to be Class 1 and MUST be earthed to the distribution board. It's not illegal to use a stepdown Tx to convert 240 to 110/100V but the equipment MUST adhere to to the relevant safety standards.

I suspect Zin will be meg ohms. We used switchable decade resistor boxes for the tests you could do something similar with regular metal film resistors your uncertainty will be a few % but it'll get you close enough.

Andy, you can measure Zin of the 1st gain stage. Just use a 1kHz tone and a variable resistor measure the voltage across the variable resistor and when it drops by 1/2 then the variable resistor will equal Zin of the 1st gain stage. This method is used in the Cal Lab to verify Zin on scopes etc.

The SP10mk2 PSU is 20w and it's motor has nearly 3 times more torque

Correct, I built the phono pre and by choice didn't add load resistors. The plan was to use external load plugs in the MC stage. The MC of my phono stage has 60 and 70dB gain.

I should have mentioned this is a low output Opus 3 so I use the MC input of my phono pre (60dB) which has no loading and I use load plugs. I tested this because I suspected there was a peak around 10kHz. I did test 47kR but didn't recorded the results and I can't remember what the plot was. The loading has transformed this already very good cart into something astounding. The detail this thing extracts from the groove is amazing.

I'm a retired tech and have been fixing electronics for nearly 50 years. I too have used Weller, Hakko and Metcal rework stations. My favorite was the Hakko. I didn't like the Metcal. I also didn't use the de-soldering station I always use a Goot solder sucker and solder wick along with flux paste/liquid. Now retired I use 2 relatively cheap eBay temperature controlled stations for both SMD and through hole. They use Hakko tips and the only downside from the Hakko is the short wand lead. The secret is to run the iron as hot as possible with the biggest tip that'll fit and get in/out as quickly as possible. I run my irons at 300C for lead and 450C for lead free and larger jobs. Although now I'm not working I only use lead solder which we were not allowed while on the bench. In older PCB's de-soldering ground planes is the hardest because the large amount of copper soaks heat and leaves the hole still full of solder, I drill the hole by hand with a PCB drill in a pin chuck.