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Old 11th February 2013, 06:42 PM   #581
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find something like this print
Loudspeaker Protection and Muting
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Old 11th February 2013, 06:46 PM   #582
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or this from velleman
Velleman nv - Item - Details
looks this ok
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Old 16th February 2013, 07:38 PM   #583
Desmo is offline Desmo  Denmark
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Update on using the fixed resistor instead of the multiturn trimmers for setting anode voltage... As expected there is zero drift, and the preamp is as quiet as most non dht preamps... Nice
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Old 17th February 2013, 06:47 AM   #584
kazap is offline kazap  Australia
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Quote:
Originally Posted by Desmo View Post
Update on using the fixed resistor instead of the multiturn trimmers for setting anode voltage... As expected there is zero drift, and the preamp is as quiet as most non dht preamps... Nice
Excellent news.

May I ask a beginner question? Is this drift something that happens with the stock regulators, or is it just the Coleman modded regulators that drift?
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Old 17th February 2013, 10:03 AM   #585
Desmo is offline Desmo  Denmark
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You have short Tram II-upgrade-memory If you look back a few posts you will notice that the drift is on the 120V DC anode voltage due to the multiturn trimmer on the CCS module. You will also notice your own comments on the fixed resistor, so I think you have read it
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Last edited by Desmo; 17th February 2013 at 10:06 AM.
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Old 17th February 2013, 11:46 AM   #586
kazap is offline kazap  Australia
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huh, whats the CCS trimmer?
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Old 17th February 2013, 12:00 PM   #587
kazap is offline kazap  Australia
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Ive shot some temperature readings of the Tram2 guts with the base off.
Click the image to open in full size.

I got bit of a surprise with 69C on the standard regulator transistor body or whatever the thing is in the middle of the heat sink. That was just running 45's with the base off and 26C ambient temperature.

I wanted to try my 2A3 RCA VT95 2A3 that finally arrived so I committed sacrilege put a fan under the Tram2. Running the 2A3's the temperature came down to 39C. That was with the 120mm computer fan on 2/3 power so I turned the fan to the lowest setting. The temp is now to 46C which Im happy with. The fan is vibration and noise free as its just idling running on the lowest setting and reduced voltage via a linear power supply. I hate to think how hot the regulator would get on a still hot day with 2A3's in it and the base on.

The 2a3"s were no noisier then the NOS 45's with a quiet hum with ear to speaker. I put an old tin can over the 2A3's supported on blutac to allow an air gap for draft. The hum went completely with no need to have an earthing wire on the old can.

I like the 2A3's I got with a bigger more dynamic sound as the initially impression while still maintaining the .timbre richness of the 45's

I also dimmed the front panel LED;s by filling the holes with blutac. Now they glow faintly.

See I can do DIY. Now I just have to work out what that CCS thingy does.

Last edited by kazap; 17th February 2013 at 12:06 PM.
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Old 17th February 2013, 12:14 PM   #588
Desmo is offline Desmo  Denmark
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Originally Posted by ThorstenL View Post
Hi,



The Resistors are R8 & R11, original 390 Ohm.

They are one each on the actual controls section (with LED's and rotary encoder) of the PCB.

Ciao T

Instead of stuffing the holes with bluetac I suggest you change the resistors that set the level for the led's. I change them from 390 ohm to 2K2
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Old 17th February 2013, 12:24 PM   #589
kazap is offline kazap  Australia
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Originally Posted by Desmo View Post
Instead of stuffing the holes with blutac I suggest you change the resistors that set the level for the led's. I change them from 390 ohm to 2K2
Yep - I read your posts and T.L.'s but when I looked to do the same thing I couldn't see those resistors. I think they hid them on the wrong side of the board next to the front panel blocking easy access and I further suspect they are those little surface mount resistors which look hard to de-solder? It looked too hard for me anyway. Im pretty handy with blutac though and I bet my Tram2 is unique now between the old cans and the blutac.
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Old 23rd February 2013, 12:46 PM   #590
Desmo is offline Desmo  Denmark
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I don't know how to say this, but the bluetac solution is... hmmm... crap..! If you have too bright bulbs in your lamps, do you then cover the bulbs with a coat of bluetac? Or do you put in bulbs that are less bright? The resistors are on the ''right'' side of the pcb, and the smd resistors are very easy to remove. Just heat them until they fall of, solder the leaded resistors in instead. 5-10 minute project... In this picture you can see the location of the resistor (red resistor, leaded type, just to the left of the grey connector).
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File Type: jpg IMG_4121_2.jpg (123.8 KB, 98 views)
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Last edited by Desmo; 23rd February 2013 at 12:49 PM.
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