Leak TL/12 Plus / Point One Plus (2024)

Tony L

Administrator
  • Dec 15, 2017
  • #1

The Leak gods have been smiling on me lately as not only did I find an almost certainly NOS Stereo 20 recently (see my lengthy Stereo 20 thread) but I’ve also over the past month or so landed a first version champagne colour Troughline tuner (mono), a Point One preamp (mono), and today a later-look Varislope Stereo pre and the real star this little TL-12 Plus mono power amp:

Leak TL/12 Plus / Point One Plus (2)

I landed it for £200 with the slightly tatty and far less collectable black/silver Varislope pre. As is often the case it has scrubbed up better than I could have ever hoped on first look (it was filthy) and it looks unmolested with no sign of any work let alone the nasty botches that blight so much Leak kit these days:

Leak TL/12 Plus / Point One Plus (3)

Not decided what to do with it yet, I’ll likely keep an eye out for a similar condition and similar colour (IIRC this is the first and most collectable colour) little friend for it and then restore them as a pair.

Has anyone any view as to how a pair of these compares sonically to the Stereo 20? (stock spec, I’ve no interest in butchering anything!). It looks like the same output transformer as the Stereo 20 (I assume the first version) but it has an EF86 and ECC81 ahead of the EL84s rather than the ECC83s in the Stereo 20, so I assume it sounds rather different.

Blatant plug for Servisol Foam Cleansor 30, it really is magic in a can.

April 2021 Edit: I’ll add a proper safety disclaimer to this thread:

I am not an electronics expert and this thread details the full electrical restoration of my amps. It is provided for entertainment and in no way should be viewed as more than that. Valve amplifiers contain really high voltages that can kill and you shouldn’t embark on a project such as this unless you fully understand which bits are live, that capacitors can hold high voltage long after the power has been disconnected etc. I have attempted to document what I know and what I have learned as accurately as I can, but this is not an instruction manual and should certainly not be viewed as one!

Last edited:

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kitemap

Immoderate
  • Dec 15, 2017
  • #2

Very nice Leak TL/12 Plus / Point One Plus (5)

Arkless Electronics

Trade: Amp design and repairs.
  • Dec 15, 2017
  • #3

It's a long time since I heard a pair so won't comment on the subjective differences but that valve complement has the potential to give better measured performance than the line up in the St 20 as it could give greater gain with less phase shift, hence more NFB could be used OR a greater stability margin achieved.

Tony L

Administrator
  • Dec 15, 2017
  • #4

One would assume far better stereo separation too as no shared components and a dedicated PSU per channel etc. Only issue will be finding the other channel of similar date and condition!

Arkless Electronics

Trade: Amp design and repairs.
  • Dec 15, 2017
  • #5

Tony L said:

One would assume far better stereo separation too as no shared components and a dedicated PSU per channel etc. Only issue will be finding the other channel of similar date and condition!

Much over-rated factors generally. A cartridge or FM broadcast have such poor separation compared to any amp as to make it a moot point...

snowman_al

pfm Member
  • Dec 16, 2017
  • #6

Nice find Tony.
They do sound much like the Stereo 20. Just a tiny bit better bottom end maybe and again a tiny bit more energy in the higher mids. But that could be to do with component choice as much as the amp?

Barrymagrec

pfm Member
  • Dec 16, 2017
  • #7

Arkless Electronics said:

Much over-rated factors generally. A cartridge or FM broadcast have such poor separation compared to any amp as to make it a moot point...

Or Stereo / Multitrack tape machines.....

Tony L

Administrator
  • Dec 16, 2017
  • #8

I’m inclined to agree given the imaging/soundstaging I’m getting from the Stereo 20 and JR149s is probably the best I have heard in 40 years of fiddling around with audio!

PS The more I think about it and look at the TL12 sitting on the shelf in front of me the more I’m determined to find it a similar condition similar period mate. It needs to be just the same as this one has the early 3921 output transformer. There is one on eBay here which looks pretty good, but ideally I’d like better paint on the front panel so I’ll let it go to get a better indication of price and then start pouncing on tidy ones as they come up.

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snowman_al

pfm Member
  • Dec 16, 2017
  • #9

Two are always better! and its not in bad condition at all.
But the little X scratched on the output transformer might make me a little suspicious... And the valves have nothing to do with it...

Tony L

Administrator
  • Dec 18, 2017
  • #10

I spent an hour or so last night giving this a real museum-grade gentle clean with cotton buds etc and I’m amazed at how well it has come up. It really is a beautiful example:

Leak TL/12 Plus / Point One Plus (14)

Front is great, logo perfect etc.

Leak TL/12 Plus / Point One Plus (15)

A couple of scratches on the big cap and the transformers, but nothing to worry about. All legitimate ageing for what has to be a very old amp, certainly older than I am! As far as I can tell this champagne with black text finish was used from when the amp was introduced in 1956 to around 1959 (which is why this finish is so rare and collectable on the Stereo 20 which was only introduced in 1958).

Leak TL/12 Plus / Point One Plus (16)

It looks totally stock to me, I can see no evidence of any servicing or changes. The green 1uF cap has obviously leaked white goo at its end, as one would expect really, and a lot of the resistors look pretty manky. I can’t see any evidence of heat under the green safety resistor (which in this case is not cut to drop), so it looks to have had a very easy life. I suspect I’ll have my work cut out finding it a similar condition pair!

PS I’ve temporarily stuck some little rubber feet on it just so it doesn’t scratch the shelf it is sitting on. They peel off again easy enough!

snowman_al

pfm Member
  • Dec 18, 2017
  • #11

The only non original component I can see is the yellow 50uF Dubilier cap marked BR 0020.

Raoul Duke

pfm Member
  • Dec 27, 2017
  • #12

Well spotted snowman.. I would say the Dubilier was not factory fitted, Tony L that is easily the best condition 12+ I have ever seen.. really looks like it was made last week! I have a few of these with the 8778 OPTs and a Stereo 20 with the earlier 3921 OPTS, cant really tell them apart running my Tannoy HPDs. Both fully recapped and reconditioned. I also have one of these early champagne 12+ but the cosmetic condition is less than stellar.

Tony L

Administrator
  • Jan 6, 2018
  • #13

Found an original ad in the August 1958 Gramphone:

Leak TL/12 Plus / Point One Plus (20)

Full res here (I now own a scanner!).

I do also have the mono Point One preamp:

Leak TL/12 Plus / Point One Plus (21)

I'm currently trying to hunt down a knob as I'm missing the gold insert for one and I'll likely eventually get it working if possible. It looks pretty tidy inside and there is a lot less in it than the later stereo Varioslopes.

PS The boxed late grey Stereo 20 I found a while back (see Stereo 20 thread) has the octal pre-power link cable, anyone know if this works in a mono context too, i.e. can I use it with this combo?

snowman_al

pfm Member
  • Jan 6, 2018
  • #14

''PS The boxed late grey Stereo 20 I found a while back (see Stereo 20 thread) has the octal pre-power link cable, anyone know if this works in a mono context too, i.e. can I use it with this combo?''

Yes, everything is the same. The 'stereo' version just has one more wire in it to connect to the other channel. All the Leak amps with the octal umbilical share the same convention. So a stereo lead will work fine on mono amp/mono pre amps.

Tony L

Administrator
  • Jan 6, 2018
  • #16

That could be a good deal, I doubt I’ll go for it as I’m in no rush at this stage to pair the TL12 Plus. The more I think about it the more I’m inclined just to keep this set mono as it gives the Wharfedale SFB/3 a usage context, and buying two TL12 Plusses and a Point One just to get a gold Point One knob insert seems a little extreme!

martin clark

pinko bodger
  • Jan 6, 2018
  • #17

Tony L said:

The more I think about it the more I’m inclined just to keep this set mono as it gives the Wharfedale SFB/3 a usage context

Ooh. nice idea. Suits you sir.

Leak TL/12 Plus / Point One Plus (26)

(Taken from GA Briggs 'More about Loudspeakers')

W

WillietheSquid

pfm Member
  • Jan 6, 2018
  • #18

Tony L said:

I’m inclined to agree given the imaging/soundstaging I’m getting from the Stereo 20 and JR149s is probably the best I have heard in 40 years of fiddling around with audio!

We know that's a really big part of the JR149 magic ... and it especially unlocks the imaging / soundstange potential in quality valve amplifiers ... stereo or mono-blocks. Magic forty year-old speaker in a can.

WTS

Tony L

Administrator
  • Mar 20, 2021
  • #20

I finally have bought my lonely TL-12+ a friend (eBay)!

I’ve been waiting a long time for the right one to turn up, and this one looks even better than my existing one. If I can get £200 or so back on the boxed mono preamp at some point I’ll consider it a clear win.

After selling a later grey-era Varislope Stereo preamp a while back that I landed at the same time I’m actually only in for <£80 or thereabouts on the existing one, so I should hopefully be able to build up a very nice pair of the most collectable version of the 12+ for £700 all in. That looks like a win to me! At this point I have no idea if the transformers in my existing one are ok or not, but they should be the same type so hopefully they’ll end up sounding like a pair (which is always the risk!).

I have a spare set of Russian PIO caps stashed for my Stereo 20, so I could borrow those for a while (need to check the values are the same, obviously), I’ll need to think about the rest. I’m not going to rush it. I want to do the neatest most sympathetic rebuild I can possibly achieve. They are beautifully laid-out amps so it will be easy to work on, I just need to make choices that will be the most authentic and add the most value. The annoyance is they are probably worth the most actual cash as-is in unrestored state, but I really want to hear them against the Stereo 20, so I will restore them, though it may be a slow process as I need to do a fair bit of research first.

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