Shoog
Member
Joined 2002
2017-12-31 9:38 am
#4
- 2017-12-31 9:38 am
- #4
Looks lovely - but I would recommend replacing the big filter caps. It can be done with relatively small caps under the chase - or you can gut the cap and put the cap inside. These caps are about the the worst component to die as they will likely take down your power transformer which will be a bugger to replace.
Lovely job, how do they sound ? I remember when I had a LEAK Stereo 20 that it had a real golden hang in the air quality to the sound - fairly coloured but in a nice way - classic valve sound.
Shoog
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vishalk
Member
Joined 2017
2017-12-31 12:26 pm
#5
- 2017-12-31 12:26 pm
- #5
jazbo8 said:
Very nicely done, and retains the vintage look.
Thanks Jazbo, the paint work has seen better days, i may attempt to get the paint matched and blend in whats damaged. Or maybe just completely respray the whole thing.
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vishalk
Member
Joined 2017
2017-12-31 12:30 pm
#6
- 2017-12-31 12:30 pm
- #6
Shoog said:
Looks lovely - but I would recommend replacing the big filter caps. It can be done with relatively small caps under the chase - or you can gut the cap and put the cap inside. These caps are about the the worst component to die as they will likely take down your power transformer which will be a bugger to replace.
I was very lucky in that the filter caps work, even when testing for the capacitance they measured perfectly and equally held the right voltage, although you maybe right, it is a risk.
Lovely job, how do they sound ? I remember when I had a LEAK Stereo 20 that it had a real golden hang in the air quality to the sound - fairly coloured but in a nice way - classic valve sound.
I just finished restoring the leak stereo 20, that was a pleasure to work on, i used original mullard valves and the sound for only 10w is breathtaking and actually very loud. Only thing was on xmas day one of the el84 valves decided to fail due to age i guess taking out the cathode resistor with it! So now to be safe i have replaced all the valves with brand new ones.
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vishalk
Member
Joined 2017
2017-12-31 12:35 pm
#7
- 2017-12-31 12:35 pm
- #7
Im interesting in installing a choke in one of the tl12+ power supply, has anyone done this?
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Alan4411
Member
Joined 2011
2017-12-31 2:06 pm
#8
- 2017-12-31 2:06 pm
- #8
I have touched up a 'charcoal' Stereo 20 with Toyota Decuma Grey. Not perfect, but matches the fleck pattern well and better than scratches. The other colour that comes close is Peugeot Steel Grey metallic.
Yes nice work there. I would not rush to replace the reservoir caps either if there are no signs of physical leakage and they measure OK. I found them pretty reliable on the TL12+. Not like those on the ST20 that do go low. Just check they are not getting hotter than the chassis from time to time. By the way don't forget to do the clamp up on the restored one!
Mods? Run the EF86 as a triode to reduce gain and kill some of the noise it makes? Maybe remove the heater wires off the input socket. Personally I would not do anything that could not be reversed, so drilling holes would be out. Not sure there is a lot to gain with choke filtering. But ehy it's yours and finding out is the fun part...
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Alan4411
Member
Joined 2011
2017-12-31 2:46 pm
#9
- 2017-12-31 2:46 pm
- #9
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vishalk
Member
Joined 2017
2017-12-31 5:28 pm
#10
- 2017-12-31 5:28 pm
- #10
Alan4411 said:
I have touched up a 'charcoal' Stereo 20 with Toyota Decuma Grey. Not perfect, but matches the fleck pattern well and better than scratches. The other colour that comes close is Peugeot Steel Grey metallic.
I can work with that ill check online a buy a can, i was also thinking of sending one of the old capacitors or shield of the transformer to a spray can company that match the paint and colour for you, could be worth a go.
Yes nice work there. I would not rush to replace the reservoir caps either if there are no signs of physical leakage and they measure OK. I found them pretty reliable on the TL12+. Not like those on the ST20 that do go low. Just check they are not getting hotter than the chassis from time to time. By the way don't forget to do the clamp up on the restored one!
Very well spotted on the clamp! I did before i set it up, good to know the reservoir caps are good to go and reliable.
Mods? Run the EF86 as a triode to reduce gain and kill some of the noise it makes? Maybe remove the heater wires off the input socket. Personally I would not do anything that could not be reversed, so drilling holes would be out. Not sure there is a lot to gain with choke filtering. But ehy it's yours and finding out is the fun part...
The original tl12.1 had a choke didn't it? And having a choke would be in some way beneficial. Agreed everything i do will be reversible so no holes drilled!
its the doing and finding out part i like the most, but also the pleasure of rebuilding and making things work.
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vishalk
Member
Joined 2017
2017-12-31 5:29 pm
#11
- 2017-12-31 5:29 pm
- #11
Alan4411 said:
This is one I did back in the late 1990s.
Very nice Alan, i like the blue can caps!
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Shoog
Member
Joined 2002
2017-12-31 7:22 pm
#12
- 2017-12-31 7:22 pm
- #12
Here's a tip to watch out for, there is a resistor on the input AC which is of a relatively low wattage - don't be tempted to beef it up or change the way it is soldered in. Its designed to overheat and melt out of its solder joints in case of a short circuit in the power supply. I made the mistake of upgrading it when I did mine.
Shoog
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Alan4411
Member
Joined 2011
2017-12-31 7:26 pm
#13
- 2017-12-31 7:26 pm
- #13
''The original tl12.1 had a choke didn't it?''
Yes it did, but the reservoir caps were only 4uF (and maybe 8uF after the choke on some) so it was an essential mechanism in smoothing the HT.
There is substantially more smoothing from the much larger capacitors in the TL12+. But as you surmise, a choke will improve it still more.
Very glad about the holes!
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vishalk
Member
Joined 2017
2017-12-31 7:51 pm
#14
- 2017-12-31 7:51 pm
- #14
Shoog said:
Here's a tip to watch out for, there is a resistor on the input AC which is of a relatively low wattage - don't be tempted to beef it up or change the way it is soldered in. Its designed to overheat and melt out of its solder joints in case of a short circuit in the power supply. I made the mistake of upgrading it when I did mine.
Shoog
Thanks for the reminder Shoog! I left the original in to do it's job as it was fine.
Alan4411 said:
''The original tl12.1 had a choke didn't it?''
Yes it did, but the reservoir caps were only 4uF (and maybe 8uF after the choke on some) so it was an essential mechanism in smoothing the HT.
There is substantially more smoothing from the much larger capacitors in the TL12+. But as you surmise, a choke will improve it still more.Very glad about the holes!
I wonder if it makes a difference in terms of bass and low frequency notes, that's really my aim, nothing major just smooth out the HT a little more.
I guess at the the time when they built and revised these amplifier circuits everything was perfected and done to the best performance and ability, so things like available components at the time and sticking to budgets!
I'll give it a go, although ill be damned if i can figure out what i need, what electrical calculations would i need to even start with to find a suitable match for the leak circuit.
From reading other members on forums it seems something like a 5H 200ma choke will suffice.
If anyone can help with regards to the above please do let me know.
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vishalk
Member
Joined 2017
2017-12-31 8:14 pm
#15
- 2017-12-31 8:14 pm
- #15
Pair of Leak TL12.1 | AudioWoof
Oh my these are lovely looking TL12.1's
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M
multi
R.I.P.
Joined 2011
2017-12-31 9:42 pm
#16
- 2017-12-31 9:42 pm
- #16
I think the TL12+ is a much better amp than the TL12 the out put transformer gives very little bass. hard to imagine cost the TL 12 goes for on EPay.
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Shef
Member
Joined 2015
2018-01-01 12:09 am
#17
- 2018-01-01 12:09 am
- #17
Indeed, neat job and eye-candy to see. Any schematics mods on mind?
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Alan4411
Member
Joined 2011
2018-01-01 6:40 am
#18
- 2018-01-01 6:40 am
- #18
vishalk said:
I'll give it a go, although ill be damned if i can figure out what i need, what electrical calculations would i need to even start with to find a suitable match for the leak circuit.
From reading other members on forums it seems something like a 5H 200ma choke will suffice.
First work out the total current the choke will handle. Measure the voltage drop across the green 100 ohm resistor. (The 'safety' one referred to above. Actually in the HT DC line.) In a TL12+ it should be about 8 volts DC. From Ohms law calculate the current. In this case around 80 ma. Your choke needs to be larger to avoid saturation. So a 100 ma / 120 ma choke is fine.
Next consider the choke DC resistance. I assume you are going to replace the green resistor with the choke, so it needs to be in the 100 ohm range. If it is more you loose HT volts and vice versa. If you intend to put it between the rectifier and green resistor, you will loose HT volts and need to add another smoothing cap...
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