mwl168

Have not worked with TPS7A. Hand-soldering a tinny part on a small PCB is a challenge by itself. Add high voltage application which is not forgivable if the soldering job is less than tidy.

Table updated! Also, some progress updates: I tested the timer, relay and LV sections on the Main Board and they all work as designed. I am very close to sending final boards to fab house for quotes. With some luck with remaining tests, it may happen this week. With that in mind, a few things we need to all think about and decide. Please share your thoughts on this thread: 1. A reminder - the GRHVxxx and GRLV boards will not work by themselves as stand alone regulators. The rectifiers, filter caps, current limit circuit for HV are on the Main Board. 2. You can use 78xx/79xx regulators to replace GRLV boards if so desired. In fact, that's how I tested the Main Board. 3. The default timer setup on the main board is about 45 seconds. You can change a couple parts to adjust. The timer and relay circuits are both optional and can also be replaced with external modules. 4. R7, 8, 9, 10 on the GRHVxxx board set the regulated output voltage. A couple of items to think about and decide: 1. We should consider, as I have mentioned before, if to have the GRHVxxx board either fully or partially assembled. I hand-soldered all the SMD parts on the main board. It's manageable. The GRHVxxx is another matter - it's small and operates on very high voltage. Soldering the HN4A51J part alone is no bargain. 2. This GB has dragged on for some time. If you have changed your mind about the item quantities, etc., please post them here and I will update the table. We need final counts to get quotes. More update to follow!

Happy Birthday Craig!

How does the pickled tap taste?

if you are referring to the large filtering caps, those extra holes were provisioned for builders to use various brand of caps in the position including the boutique Mundorf caps IIRC. The extra holes to the side were there to help with mechanical security of the caps (if so equipped) as some builders choose to mount the boards vertically on the heatsinks.

Empire turntable and Sausui pre-amp?

I was inquired by PM about the board size so I'll post the information here for all. Do keep in mind the dimensions are of the current boards and, though not very likely, there is no guarantee that the dimensions will not change when final testings are all completed. The mini T2 boards are 160mm x 100mm. The PSU main board is 140mm x 89mm. Keep in mind the way the PSU main board is laid out means the footprint needed will depend on how you decide to mount the GRHV and GRLV boards.

There is an alternative way of looking at this - think of purchase like this as an insurance/investment if the price is within reason. Given the scarce of these tubes, it's not unreasonable to think that down the road one should be able to sell them for the same if not more dollar amount if one decides the tubes do not justify their cost. At least that's what I try to tell myself from time to time 😉 The challenge though, is establishing what is a "reasonable cost".

Sure hope so! I am sure that shelf is hoping the same!

I really wonder why the power amps are on the shelf and the turntable is on the floor? Not the way I would do it.

Trying a set of loaner xf1 EL34 on the BH. Hoping to get a handle on how they compare to the xf2's and xf3's.

I agree with Pars - that's the real emerging market. I don't see audiophile-oriented headphone products being embraced by average people. Most people I know and work with look at me strange when I told them I use a headphone amp when I listen to my headphone. Most of the time, the next sentence is "what the hell is a headphone amp?".

I hope the floor is sturdy enough...

Table updated.

Another updated BOM from JoaMat in the first post. There is a URL link in the BOM spreadsheet.Copy and paste this URL onto a web browser will take you into Mouser website with the BOM loaded and ready to be ordered (click on it in the spreadsheet won't work). Very slick! But, as always, do check for correctness and stocking status of each part.

In case this is of interest to anyone. Took me a while to find it: Kester 44 Sn62Pb36Ag2 (2% silver eutectic) solder in .025"/.6mm diameter. Very good price too - $55.18USD in 1lb spool. Typically found them at over $100 USD with 25 minimum order. Vendor is Concorde Electronics, part # 24-7150-0018. https://www.concorde-electronics.com/products/kester-24-7150-0018.html Bad news - shipping is $12.26 USD, good news - fast shipping. Got it in 4 days. I set out looking for the one in .02"/.5mm diameter (24-7150-0010) and finally found it at R.S. Hughes with no minimum order and less than $100 USD. Only to be told a few weeks after placing my order that they do not have it in stock. EDIT: I found this .025"/0.6mm diameter solder to be a good compromise between soldering of through-hole components and SMD. It works well for most SMD except those really tiny ones which I still prefer the .02"/0.5mm diameter. But the .02"/0.5mm diameter solder is a bit too small for through hole component soldering.

Thanks to JoaMat - I just posted updated schematic and BOM in the first post of this thread.

I am not picky. I like them both!

Maybe it's the size of the room they are in ...

Also curious about the build quality - how does it compare to the Stax products?

The cat does look, uhh, plump...

Is the packaging the only difference between the standard and premium versions? The website shows that the premium version is sold out and does not give a price.

These days I take a somewhat pessimistic attitude toward major software updates - I wait a bit for it to mature before jumping on board given a choice. Software vendors no longer test the new release as thoroughly as in the past before releasing it to the public and I speak from firsthand experience. The early adapters are more like beta testers these days. I did not have a choice and had to upgrade my office-owned iPad to the latest iPadOS version recently. While I am sure the new OS is more secured (main reason for the upgrade), many things just do not work right and will likely take a few patches to rectify.

Using the proper washer with the tube long enough to extend through the tab of the sand into the ceramic insulator is mandatory when you use the steel screw as Jose stated. Craig had a great post where he explained and illustrate the reason why somewhere in the forum.

Table updated!