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[#1851] LEAK TL12.1 restoration This easy-to-access "tag-board" (same as LEAK TL12.1's tag-board, just when a replacement is needed. I have some stocks) 最後修改時間: 2025-11-22 12:55:56		rcwy 正式會員 118.xxx.xxx.29	2025-11-22 12:49

[#1850] LEAK TL12.1 restoration

Thanks for sharing. South Africa is a very different world and happy to know you and your world.

Are there electronic components shops around your town/city, or you must buy from online shops?

If you can source your own supplies, try the restoration by yourself, given one of the purposes of LEAK TL12.1 having easy-to-access "tag-boards" is for EASY repair/restoration!

I know some idiots in electronics could do restoration themselves. Just read the users manual of a good multi-tester 萬用錶 for measuring AC/DC voltage, ohmage of resistors/coils, capacitance of caps - Just junior secondary school physics is sufficient (if can remember the lessons).

You probably need courage and carefulness in handling high voltage e.g. over 100/200V AC, over 400-500V DC more than electronics knowledge. Skills can be grown with more and more practices in using a soldering gun!

Back to your concerns about EF36 vis-a-vis EF37A in your TL12.1s, it should be absolutely clear in mind that two normal working EF36/EF37A tubes should give very similar performance (except that EF36 is more sensitive to RF interferences) to the extent that none should be "softer" (except when one of the tubes is in fact weak and out of its spec).

Get two new-old-stock (NOS) EF37A tubes to replace them.

最後修改時間: 2025-11-22 06:14:14

rcwy

正式會員
118.xxx.xxx.29

2025-11-22 06:00

[#1849] LEAK TL12.1 restoration
I have 2 pairs. I am referring to the bottom picture which shows one of a pair. The top picture is a different pair and not part of this question. Referring to the bottom one it looks different now because it was recently recapped and some resistors were replaced. The recap was not done by me because I do not have the skills. But I have since found a solution to the imbalance problem. A very strange thing. I found if I use EF36 in the pair the balance is restored. But with EF37A there is an imbalance. The technician can’t explain it either.

I am in South Africa.

最後修改時間: 2025-11-21 19:43:48

hennietaljaard

新會員
160.xxx.xxx.66

2025-11-21 19:37

[#1848] LEAK TL12.1 restoration
Re. #1845 (and #1816 & 1819)

Are your pair of TL12.1 (of which one unit has "softer") the same as you shown before (pictured below)?

Obviously they are very different internally and need to be restored to be the same. Where are you based? USA/UK/? ?

最後修改時間: 2025-11-20 20:37:06

rcwy

正式會員
118.xxx.xxx.29

2025-11-20 20:31

[#1847] LEAK TL12.1 restoration
四/五十年前的老機器，零件愈原裝，毛病愈多，誤差愈大，聲音愈差。
既已拆下舊電容，為何不順道測量一下電阻呢？

羅密歐

正式會員
219.xxx.xxx.65

2025-11-20 18:22

[#1846] LEAK TL12.1 restoration
I could also mention the amps had a full recap but some of the resistors are still orginal. The tubes is fine. But weirdly one amp plays softer than the other. Anyone ever encountered this problem?

hennietaljaard

新會員
41.xxx.xxx.181

2025-11-20 14:37

[#1845] LEAK TL12.1 restoration
Hi
Has anyone ever encountered an imbalance in volume between their Leak 12.1 amps? I have a problem with one amp playing softer than the other one. I have swopped the valves between the amps but the problem remains.

hennietaljaard

新會員
105.xxx.xxx.26

2025-11-20 04:26

[#1844] LEAK TL12.1 restoration
Thank you kindly for the reply.

This morning I replaced the KT66 with 7581A and my first impressions are favorable.

After listening for 2 hours I find the sound is clean, chimey, delicate, focused and well balanced. Bass is slightly less (compared to GEC KT66).

I will say the GEC has a slightly warmer & natural tone.

The differences are small.

They are new production Tung-Sol 7581A.

I can live happily with them.

Other tubes are:
Mullard EF37A
Mullard ECC33 (yellow print)
Mullard GZ32

最後修改時間: 2025-09-01 17:51:45

hennietaljaard

新會員
105.xxx.xxx.140

2025-09-01 17:49

[#1843] LEAK TL12.1 restoration

Re. 1841

As checked the Duncan tube data sheet, 7581A has exactly the same pin-outs as KT66 (including G3 internally connected to cathode), and 7581A anode Va and Vg2 tolerance a are slightly better than KT66's. It should be a good substitute for KT66.

On added benefit is 7581A's heater current is 0.9A vis-a-vis KT66's 1.27A, i.e. it consumes lesser current.

Soundwise, you should compare by your ears and let us know your findings.

最後修改時間: 2025-09-01 14:03:27

rcwy

正式會員
118.xxx.xxx.29

2025-09-01 14:00

[#1842] LEAK TL12.1 restoration
According to the tube data sheet for 7581A it is "unilaterally interchangeable" with the 6L6GC. Should be good in Leak 12.1?

hennietaljaard

新會員
105.xxx.xxx.140

2025-09-01 12:35

[#1841] LEAK TL12.1 restoration
Hi
Can I use the 7581A tube in my Leak 12.1 instead of KT66?

I've been using 7581A in my Quad II amps without any problems.

7581A is said to be (from internet);

"an upgraded 6L6GC tube but willprovide more headroom than typical 6L6GC tubes. The 7581A power tube has a plate dissipation rating of 35W, as opposed to the 6L6GC and 7581 rating of 30W."

hennietaljaard

新會員
105.xxx.xxx.140

2025-08-31 22:20

[#1840] LEAK TL12.1 restoration
我又八卦建議一下

很不錯的

這種東西工廠用了廿幾年，我2019年開始就冇回到中國工廠

2017年最後一次安裝這種輪，在一些測試儀器底架下，質地不錯，好穩定，水平調教暢順

應該適合這個重型喇叭底座，如果高度適合都建議使用

嘩這位主人家好多有趣嘅玩具呀

hahayanyan

正式會員
86.xxx.xxx.47

2025-07-30 15:57

[#1839] LEAK TL12.1 restoration
Rcwy hing

多謝多謝

嘩對喇叭好靚

hahayanyan

正式會員
86.xxx.xxx.47

2025-07-30 15:52

[#1838] LEAK TL12.1 restoration

Haha 兄,

當你回香港, 有機會的話, 介紹你認識 FSM 喇叭的主人, 或許, 大家一起來吹水.

rcwy

正式會員
118.xxx.xxx.29

2025-07-30 11:40

[#1837] LEAK TL12.1 restoration
嘩好靚好靚

這種排版方法除了是對以往設計的一些尊重，這個年代我有一啲 marshall 膽結他 amp，都是這樣的

都幾十年人們累積零件與零件之間的排位幹擾等等等的認知增高了

是否還是一種在擴幹擾互相幹擾，可接受的設計呢？毫無疑問相比起其他的搭棚技巧維修各樣都是方便很多

真係好靚好靚

如果有機會可以分享一下 tannoy FSM 的聆聽感受就好了

thx you

最後修改時間: 2025-07-28 17:57:08

hahayanyan

正式會員
86.xxx.xxx.47

2025-07-28 17:54

[#1836] LEAK TL12.1 restoration

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