The Fuji Feather track bike and Formula hub

2 years ago I was looking for a fixed gear when I saw a used Fuji Feather track bike.

It was advertised as a single speed and I just assumed it will be easy for me to convert it to fixed gear.

I was wrong 😅

Apparently the fixed gear side of the hub is splined. It's my first time to see this type of mount. I then researched and learned that this splined mount is currently used in bike's disc brake system and is called 'centerlock'.

I didn't want to replace the hub to keep the bike as stock as possible.

So upon learning how it's called I was again positive that I can find the sprocket/cog for this hub.

I was wrong - again! 😂

Took me some time to find 2 alternatives:

1. The disc hub from https://www.velosolo.co.uk/shopdisc.html that cost GBP35++ - sold from UK and ebay

2. The exact "formula" cog that is only sold in Indonesia - advertised as "Taiwan Formula Cog"

How crazy is that - a Japanesed bike with a hub from Taiwan that is only sold in Indonesia 😜

I alson sent an e-mail to Fuji (US) asking for the splined cog but they said it wasn't availble. Major disappointment :P

Based on the 2 available options - I decided to DIY my cog with a centerlock disc brake mount and a cog from a single speed conversion kit.

I painstakingly drilled 3 holes on a solid steel cog and hoped for the best that they will align on the 3 holes (of 6) on the centerlock adapter.

Long story short, I was able to build my cog.

Once, during a long ride - the bolts on the DIY cog loosened and I had to call for SOS so I can go back home 😆 Stress and vibration can actually loosen bolts so learning from this, I put a considerable amount of thread locker on the 3 bolts. This solved the issue.

But I still desire for the splined cog on the hub which apparently was made by Formula(?): https://theradavist.com/formula-hubs-centerlock-spline-fixed-hub/.

I know people from Indonesia (office/work related) and I just hoped then that I can ask them to order for me online and wait for some people to travel JKT-MLA 😁

After 2+ years the wait was finally over and now my Formula hub is reunited w a Formula cog 😎

The DIY centerlock rotor adapter and drilled cog with the Formula cog (15T)

close-up

The Formula centerlock/spline hub

fits nicely

used a spare new lockring

let the lockring push the cog inside

installation complete

The Sony XDR-S3HD Radio (3 yrs after)

I have a REL Quake lying around after building a speaker setup w 'dual or stereo subwoofer'. Almost sold it but decided to 'fix' it.

Was very surprised it paired well (size and sound) with the S3HD radio :)

I'd listen to these pair when I'm in the mood to listen to music while W'ingFH.

Since the radio came from US and has a 110V PSU, I actually bought a step down transformer that I use with it. REL plugs straight to the outlet since its 220V.

Didn't know it will cause me trouble one day when I wanted to listen to the setup and after I plugged the REL and step down transformer straight to the outlet - I also plugged the S3 PSU to the outlet forgetting about the transformer *facepalm*. 110V PSU RIP T_T

 I went to some local repair shops to inquire about salvaging the transformer w rewind but they all pointed me to Raon (Manila) which is quite far from me. And I doubted they can do it for me since it's already burned/shorted. PLUS I'm not sure what are the voltage output of the PSU since the online service manual says ~10v/~5V and 12V/7V. Yes, the PSU is dual voltage. Something that surprises some people :D

So I started looking for a dual voltage power transformer but they are mostly available only from the likes of Digikey and Mouser where one has to order php2K to get free shipping. While the transformer I need only cost around php600 - I presently didn't have other electronic related stuff to order. So I kept searching lazada and shopee... also went to ebay, amazon, etc etc... but to no avail T_T

Based on the google results, I then decided to make my own dual voltage supply from a single transformer based on circuits using power transistors that converts voltages to distinct output based on the transistor code e.g. LM or AN 7812 = 12V, LM or AN 7805 = 5V.

So I bought the parts from my fave local elex shop: OHM using the diagram from https://www.circuits-diy.com/12v-5v-dual-power-supply/. Quite surprised the parts are really very affordable.

Then proceeded to arrange them on a generic pcb - my 'first' time to actually build something without a premade pcb! So I was very careful and made sure I am following the circuit diagram. 220V is not a joke :D Long story short - I was able to make it work using 12V and 6V supply. Unfortunately, the 6V rail gets really really hot so I abandoned it.

I was then thinking I'm really forced to get the dual voltage from digikey and just get some stuff to reach php2K to get the free shipping. But before I proceed with the purchase - I really  wanted to make sure I'm getting the correct output. I actually sent an email to XDRguy (David Stambaugh) and he said 12.7V and 7.2V. Unfortunately for some reason, there is no power transformer that converts to 7V! So weird. And I didn't want to venture into LM317s anymore :D

And so I was ready to order from digikey but I accidentally got the correct search words on shopee and found a dual voltage power supply:

"Adjustable Dual Double Double Output Dual Module Switching Power" :D

It's not even available in lazada. Kinda pricey but it's better than building from scratch.

Long story short I got the S3HD working again... and I really had a great 'adventure' from that 'mishap' - soldering 2 versions of the dual supply :D 

Just ordered a case for the new dual voltage power supply :)

 The Sony XDR-S3HD Radio

A long time ago I bought the Sony SRF-S84 pocket radio which got rave reviews from audio sites. I even used it with the Sony Fontopia earphones.

Fast forward to 2020, my interest with tuners was 'reactivated' due to the pandemic. Mostly working from home and got more time with my hobbies.

Got interested with its sibling - the SRF-M35 which some say sounds more 'audiophile' than the SRF-S84. I ordered one from ebay. I then confirmed I preferred it sound over the S84. S84 sounded like EQ'd while M35 sounded more natural.

After the M35 I googled tuners and encountered the Sony XDR-F1HD which I believe was introduced on 2008 and was then discontinued by 2012. Price was ~USD99.

Nowadays, the unit is fetching ~USD185 in ebay because its very famous among DXers. Not to mention common tuner-persons also like it due to its very good sound quality. I wasn't 'willing' to spend ~$185 for this unit based on the issues like 'overheating' and 'rolled-off treble' so I googled some more until I encountered its cousin: the XDR-S3HD. Actually there's one more which is the XDR-S10HDiP. It is commonly know that all 3 radios have the same internals but the heat and treble issues were already addressed on the newer cousins. The F1 had line out, the S10 had only line in and the S3 have line in and headphone out. Both S10 and S3 have built-in speakers. I'm just surprised Sony remove the line out in the S10. All three models are discontinued btw.

@ebay, the S10's average price is ~$45 while the S3 is ~$70. The S3 (wood) is way heavier than the S10 (plastic) but it really looked better and should sound way better. S10 doesn't have a headphone or line out so I'm left with the S3 - I just have to bear with the shipping cost :D [edit: authorized this for sea freight but was sent to me via air \m/]

To cut the long story short, I am very pleased with the S3HD. The headphone out going through my passive attenuator (LDR) then to the power amp sounded good. I then had to try the power amp connected directly to the S3 thinking it should sound better. The Sony radios all come with remote controls (but rarely sold used with it). If I can use the S3's line in then the power amp connected to it - then I should be able to remotely adjust the volume control (VC). The S3's volume control is in the digital domain so I'm also assuming it should sound great. Unfortunately, there is quite a noise when the power amp is directly plugged in the headphone out. Not surprised here since the headphone out is already amplified.

Torn between "not giving up on the idea of remote controlled digital volume control" and "didn't want to open it up anymore" - I got curious what can I see from the bottom 'window' where the fan is sitting... it's fairly very easy to remove with just 4 screws and the 'window' is quite big.

Took a pic and downloaded the service manual.

And after some time going back and forth the picture and the manual... lo and behold - the pre amp chip is there staring at me :D The rest as they say is history :)

Reminds me very much of the Dared MP5 pre out mod.

Here are some pics on the mod.