The end of the (upgrade) road?

[Macca]

Not necessarily. My 1200 works fine (I don't know exactly how old it is since it is from a 'zero' year so could be 1990 or 2000) but the previous one I had was either 1980 or 1990 and that was also fine.

Although it is widely claimed that capacitors always degrade it's by no means universal. If the deck spins at the correct speed then there's no problem to solve.

[Tim]

If you Techie is from the 80s, the capacitors are 40 years old, so due a change.

My 1210 is from 1988 and I was thinking that myself, but I got some advice from a couple of turntable trade guys and Jez Arkless, who all said to leave it alone if it was running fine, which it is. I'm not competent enough to know which is the best advice, so that's kind of why I bought the other main board from Japan. Not just to have the IC chips AN6680 & AN6675, which are getting expensive now (often more than I paid for the board for just one), but to have a full backup.

So I won't do anything now until something fails, then I'll swap the board out and fix the one that's faulty, so the deck should always be functional - that's the theory anyway

[CageyH]

I would listen to the professionals, and not some SL1200 tinkerer.

Much to my dismay, I was still getting occasional and what seems like random hum from my BB3, so last night I swapped the UF4007 out for some Vishay SF4007, as these are supposed to be an upgrade. I was also not sure what UF4007 I had fitted. They may have been generic parts I purchased from Amazon to try and fix the issue.

Listening to my system in my lunch break for the first time, and I am surprised at the difference changing these diodes out has made.
I tidied up the input/output/loading connections whilst I was in there , but I am almost at a point where it sounds too bright.
I am going to have to wait for it to warm up and reassess later.

My new output capacitors should arrive tomorrow, so if I don't like the SF4007, I have some proper UF4007s to drop back in whilst I am changing the output capacitors.
The advantage of the SF4007 from what I have read is that they are supposed to help create a "blacker background" which is probably useful in a phonostage.

Time will tell.

[CageyH]

It has warmed up now.
It sounds much better now that it has. I had never really noticed a big difference before.

[CageyH]

And part of the difference is down to the Mazda Silver plate 12AX7S that was fitted.
Not the best match with an AT20SS.

[Macca]

Funny how Mazda were knocking out valves and cars.

Imagine if you could get British Leyland valves.

[CageyH]

As you probably alreadyknow, they only share the name.

When looking into where Mazda vacuum tubes (valves) were made, it helps to clear up a common bit of confusion: the "Mazda" brand name was historically shared by completely separate corporate entities across different countries, none of which had anything to do with the Japanese car manufacturer.
Because of complex licensing and trademark agreements tracing back to General Electric (USA) using the name "Mazda" for high-efficiency incandescent lamps named after the Zoroastrian god of light (*Ahura Mazda*), you will find Mazda valves from three primary regions:

1. United Kingdom (British Mazda / Ediswan)
The most common Mazda-branded valves found in classic British hi-fi gear, guitar amplifiers, and radio sets were **made in England**.
The Manufacturer: They were manufactured by Ediswan (The Edison Swan Electric Co.), which later became part of British Thomson-Houston (BTH) and Associated Electrical Industries (AEI).

The Factories: The vast majority of authentic British Mazda valves were produced at the historic Ponders End factory in North London. Later production also came from facilities in Sunderland and Bristol.

Characteristics: True British Mazda valves (like their highly regarded ECC83, 6P15, or UU series rectifiers) are famous for their rugged construction and high-quality internal engineering, often featuring highly distinct anode stitching or unique structural geometry compared to their Mullard counterparts.

2. France (La Compagnie des Lampes / Mazda-Belvu)
If you run across vintage Mazda valves in continental Europe, they are highly likely to be made in France.
The Manufacturer: La Compagnie des Lampes (CdL) owned the Mazda trademark in France. They manufactured lighting and thermionic valves under the MAZDA and Lampe Mazda banners. They also operated under the Mazda-Belvu and CIFTE umbrellas.

The Factories: The primary manufacturing hub was at the historic Ivry-sur-Seine plant just south of Paris, with secondary production coming from workshops like Saint-Pierre-Montlimart near Cholet.

Characteristics: French Mazda silver-box or military-spec tubes (such as French-made 12AX7s, 6V6GTs, and unique pentodes) are highly prized by audiophiles today for their exceptionally clean, detailed sonic performance and incredibly low noise floors.

3. The "Foreign" Stamped Relabeled Valves
As the golden age of vacuum tube production began to wind down in the late 1960s and 1970s, the British and French Mazda entities increasingly sourced valves from other global manufacturers to meet replacement market demands, stamping them with the Mazda logo.
Depending on the production era and specific valve, a "Mazda" stamped tube might actually have been manufactured by:
Mullard (Blackburn, UK) or Philips (Eindhoven, Netherlands)
Tesla (Czechoslovakia) — For example, many Mazda-branded 6X4/EZ90 rectifiers are actually premium-quality Czech Tesla 6Z31 production.
EI (Yugoslavia) or Tungsram (Hungary)
RFT (East Germany)

How to check: If you are trying to verify a specific pair of Mazda valves for a phono stage or preamp, look closely at the glass near the base. Authentic British production often features etched factory codes or structural traits like heavily stitched/folded gray plates, while French-made versions frequently carry specific batch codes or distinct silver internal shield plates.

[Macca]

As you proba ly alreadyknow, they only share the name.

I didn't know that, I always assumed it was the same company or at least part of the same group. Interesting.

[Alex_UK]

Every day’s a school day! Thanks for that Kevin, interesting indeed!

[CageyH]

One thing I am happy to report with the change to SF4007 diodes in the HV stage of my BB3 is that there is less valve hiss when music is not playing.

I have my system powered on without music playing, to see if my mod has helped cure the hum and there is noticeably less hiss "on idle".