401 birch or slate?

@dover Spoke to Matthew at AG who recommended the AS version so I ordered one for the AG/slate 401. If it makes an improvement, I’ll consider the AF one and move the AS version to my birch-ply 401. Thanks and good luck with the 301.

@noromance 
Drop in replacement. Undo 2 screws holding the top of the idler, lift out the idler wheel and drop in the replacement - literally 2 minute job. Drop a little oil on the spindle ( top and bottom ) to avoid any scouring. The bushes in the 401 were in good shape.

As an aside I have a 301 rebuild on the go and the new sintered bushes from Audio Silente look very good. I have purchased both motor bushes and idler bushes but have not installed these yet. Their idler is a good price but not in the same league as the AF.

Thank you. Was it difficult to fit? Do you use the original bushes? As you know, my new 401 is also an AG version. Early flat window, twin spark.

@noromance 
I would describe the improvement of the AF idler wheel as similar to a cartridge upgrade - the higher frequencies were more detailed, more nuanced. There were also improvements in coherency and musical timing.
When we upgraded to the Artisan Fidelity idler wheel, the 401 had already been refurbished by Audio Grail, in other words the AF idler replaced a refurbished standard idler wheel in good condition. The 401 in question also had had an upgraded platter and bearing from Peak Audio which had yielded a massive ( not hyperbole ) improvement in musical timing.
 

@dover  You said "Idler wheel from Artisan Fidelity - this added a significant level of refinement, particularly in the high end"

Could you kindly elaborate in a bit more detail what you mean? I'm tempted to get this wheel. I notice there is another offering from Audiosilente in Italy for 1/4 of the price. Thanks.

I went with slate. See my Virtual Systems entry for update.

Thanks @dover . This is very good stuff. I’ll look into the AF idler wheel for my birthday! Looks like I will go with slate. I have found a source in the US.
Not sure if I should open a new post but...If using slate, should I use an arm-board or mount on the plinth?

@noromance
From personal experience the SMD Quartz plinths built in the UK are very good. However, since you appear to have a reasonable plinth already, I would suggest you consider doing the following -

• Large platter & bearing from Classic Turntables - this improved the timing and coherence from the 401 substantially.
  
• Idler wheel from Artisan Fidelity - this added a significant level of refinement, particularly in the high end
  
• Power Supply from Classic Turntables - significant increase in resolution and high frequency purity
  

These mods I heard in a system I know well and can highly recommend. They took a fully refurbished and blueprinted 401 to another level by a considerable margin.

Looks like I'll have to import a slate plinth from the UK. Not much interest on this side of the pond and PA-based Oswald Mills start at a ludicrous $5000. 

Panzerholz? Looks like a lot of hassle.

Depends if your going to buy it or fabricate it yourself.

Its usually found in a specific layer as opposed to a multiple stacked
construction.

Panzerholz? Looks like a lot of hassle.