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Analog Squared Paper Discussion and Appreciation Thread. - Page 103

post #1531 of 3470
mtthefirst, lovely to put a face to a forum name! Hopefully it will not be long before yours arrives!
post #1532 of 3470

i got the 1L33 tubes today, but they don't function, maybe they need an adaptor (sorry bmichels).

post #1533 of 3470

solution to use the 1L33 tubes in the dl92 sockets of the tu-05 amp as replacement for the dl92 tubes:

 

i had a detailed look at the the pin layouts of both tubes on radiomuseum.org:

 

http://www.radiomuseum.org/tubes/tube_1l33.html

http://www.radiomuseum.org/tubes/tube_dl92.html

 

the problem is that the dl92 has two heater parts (heater ground in the middle and internally connected to g3 grid 3 pin 5 of the tube) while the 1L33 has one heater (without heater ground in the middle, pin 1 heater connected to g3 pin 5, so shorten the signal or power).

 

the solution is very easy, if you just cut pin 1 of the tubes everything works because pin 1 heater ground of the tubes is internally connected to pin 5 so the heater gets its power from pin 5 and pin 7.

 

right now i am listening to the lorenz df96 - tesla 1L33 combo. sounds promissing, will post some more detailed impressions later.

 

tesla 1L33 out of box:

 

tesla 1L33 pin 1 removed (left - without tape,  right - with a small piece of tape isolating pin 1):

 


Edited by GermanGuy - 8/7/13 at 2:21pm
post #1534 of 3470
GG, Yet again I am in awe of your explorations!

I am shipping my amp off tomorrow, apparently it takes only five days to Japan so that is great.

I forgot in all the happenings to say about my checking the three LR44 batteries used to bias the tubes. Shikada san recommends they have at least 1.4v in them for effective use, the actual voltage of the cell is 1.5v.

Checking mine yesterday (he recommend every six months) showed good news. Each cell had around 1.57v so basically the tube bias function uses very little energy.

I think in normal units the job won't be as fiddly as mine as in my unit the battery compartment is the other way round, still, it was not hard and good to know that after 7 months of being used every day the batteries are pretty much normal.

Now the countdown to all the mods being done and back to listening to my lovely amp!
post #1535 of 3470
Quote:
Originally Posted by GermanGuy View Post

solution to use the 1L33 tubes in the dl92 sockets of the tu-05 amp as replacement for the dl92 tubes:

 

i had a detailed look at the the pin layouts of both tubes on radiomuseum.org:

 

http://www.radiomuseum.org/tubes/tube_1l33.html

http://www.radiomuseum.org/tubes/tube_dl92.html

 

the problem is that the dl92 has two heater parts (heater ground in the middle and internally connected to g3 grid 3 pin 5 of the tube) while the 1L33 has one heater (without heater ground in the middle, pin 1 heater connected to g3 pin 5, so shorten the signal or power).

 

the solution is very easy, if you just cut pin 1 of the tubes everything works because pin 1 heater ground of the tubes is internally connected to pin 5 so the heater gets its power from pin 5 and pin 7.

 

right now i am listening to the lorenz df96 - tesla 1L33 combo. sounds promissing, will post some more detailed impressions later.

 

tesla 1L33 out of box:

Warning: Spoiler! (Click to show)

 

 

tesla 1L33 pin 1 removed (left - without tape,  right - with a small piece of tape isolating pin 1):

 

Warning: Spoiler! (Click to show)

 

 

 

That is impressive, GG.

post #1536 of 3470

thanks a lot for your comments. and best of all this tube set has half the power consumption of the stock ones, so should nearly double the run time of the amp!

post #1537 of 3470

to be honest i was wondering when reading that this all six months check is recommended. i think the time is more limited by the self-drain of the batteries, should be some years.

post #1538 of 3470
I am not so worried about it now as it appears to all intents and purpose that there is nothing draining the batteries. I wonder how this battery biasing works if it uses no juice from the batteries?
post #1539 of 3470

I suspect the 6 month recommendation is highly conservative. Likely the bias will only go out of whack once the batteries begin to lose voltage. Which will likely take many years, as I suspect there is very, very little current drain on them.

post #1540 of 3470
Going on my experience now I feel pretty safe in saying just once a year to check and I am not even sure that is needed. It is a little fiddly to do as well.
post #1541 of 3470

Errr...what kind of chargers came with your A2P amp? Mine came with a car charger.

 

 

 

 

post #1542 of 3470
Quote:
Originally Posted by AnakChan View Post

Errr...what kind of chargers came with your A2P amp? Mine came with a car charger.

 

 

 

 

 

 

confused_face(1).gif Car charger! Why did he give you that kind of charger?

post #1543 of 3470
Quote:
Originally Posted by AnakChan View Post

Errr...what kind of chargers came with your A2P amp? Mine came with a car charger.


Car charger plus the AC adapter. Not optimal, but I'm not complaining, as I am quite pleased with the performance.
post #1544 of 3470
Quote:
Originally Posted by woodcans View Post


Car charger plus the AC adapter. Not optimal, but I'm not complaining, as I am quite pleased with the performance.

 

Oh phew...thank goodness I didn't throw the box away. Found the AC Adapter. Thanks or the tip.

 

Yes that is kinda funky salvaging old car lighter sockets to build a Lithium charger ;-).

post #1545 of 3470
Quote:
Originally Posted by AnakChan View Post

Oh phew...thank goodness I didn't throw the box away. Found the AC Adapter. Thanks or the tip.

Yes that is kinda funky salvaging old car lighter sockets to build a Lithium charger ;-).

I totally agree. A bit of a retro/whatchamacallit fix for what otherwise is a beautiful piece of design work.
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