T, Forch here, with some unexpected bad news. The left filament heater just crapped out. This was newly replaced and included the recommended dropping resistors (0.16ohm)). I thought all as OK as it played well for a month.
Is there anyway to bypass those things or take another approach that is more reliable, even if passive and simple?
thanks, Jeff
Is there anyway to bypass those things or take another approach that is more reliable, even if passive and simple?
thanks, Jeff
Hi,
First, while I can try to help, this really needs to go through the support at diyhifisupply.
There is no such thing as "recommended dropping resistors of 0.16 Ohm".
What is recommended is the correct resistor value that will reduce excessive input voltage. You should measure with the tube in place and adjust for 5.5V AC at the input to the filament supply.
You may also want to check if the tubes you use draw excessive heater current. I recently came across a Tram that kept blowing heater supplies. Turns out it was used with "super 2A3's" that draw (contrary to their official specification) a lot more heater current than 2.5A. Such tubes will not work in the Tram II.
Not really. To be honest, if the heater voltages are set correctly and the tubes comply with reasonable specifications and tolerances, there really is no problem.
Ciao T
First, while I can try to help, this really needs to go through the support at diyhifisupply.
There is no such thing as "recommended dropping resistors of 0.16 Ohm".
What is recommended is the correct resistor value that will reduce excessive input voltage. You should measure with the tube in place and adjust for 5.5V AC at the input to the filament supply.
You may also want to check if the tubes you use draw excessive heater current. I recently came across a Tram that kept blowing heater supplies. Turns out it was used with "super 2A3's" that draw (contrary to their official specification) a lot more heater current than 2.5A. Such tubes will not work in the Tram II.
Not really. To be honest, if the heater voltages are set correctly and the tubes comply with reasonable specifications and tolerances, there really is no problem.
Ciao T
T, received the filament supplies and have the Tram back up and running. Voltage to supplies is 5.8VAC and 2.7VDC out. Biased to 120V. Tried two manufactures of 2A3 (VA and Shanguang) and each set appeared to run similarily, so I think tubes are not pulling extra current - settings were rock solid on the supplies. I will monitor it more closely to make sure I am in recommended range. Any significance between my measured 5.8VAC and your 5.5VAC target - is it close enough? Thanks, Jeff
Hi,
Should be close enough, though 5.3V would be even better. 5.8V AC creates 1W more heat than 5.5V and 5.3V creates less than that...
You can try taking one of the three 0.47 Ohm resistors in series with the AC line to the Filament supply out.also check if the Regulator chip has an isolation washer or not. If it has either Mica or silicone pads fitted remove them. In the tram this does not create any problems with high voltages on the heatsinks etc.
Ciao T
Should be close enough, though 5.3V would be even better. 5.8V AC creates 1W more heat than 5.5V and 5.3V creates less than that...
You can try taking one of the three 0.47 Ohm resistors in series with the AC line to the Filament supply out.also check if the Regulator chip has an isolation washer or not. If it has either Mica or silicone pads fitted remove them. In the tram this does not create any problems with high voltages on the heatsinks etc.
Ciao T
T, I checked by using the supplied 0.47ohm, but I could not get the voltage regulated out to stablize. I got to 5.8VAC using two 0.33ohm resistors in parallel (equiv 0.16ohm). To drop it down to 5.3, what resistance should I target? (If you could give me a value, I can start there.) Thanks, Jeff
Hi,
You should have had 3pcs 0.47, which in parallel give 0.16 Ohm (rounded).
In your case try 1pcs 0.33 and 1pcs 0.47.
Ciao T
You should have had 3pcs 0.47, which in parallel give 0.16 Ohm (rounded).
In your case try 1pcs 0.33 and 1pcs 0.47.
Ciao T
Hello
Unfortunately, the right channel of my Tram2 has kicked the bucket again. I bought the TRAM2 as an assembled item from DIYHIFI about 6 months back. I had the same problem about 3 months ago with the same symptoms - i.e. the right channel 2A3 tube wasn't heating up and hence no music. Last time round DIYHIFI informed me the problem was with the heater supply overheating. I'm guessing it is the same problem this time as the symptoms are the same. I've read over the previous posts on this so I'm wondering if anyone else has come across this problem lately, and what solution you've employed to get around this? I think Decky has tried a different type of heatsink and drilled additional holes in the chassis to improve airflow. I'm not keen on installing additional fans or putting a laptop-style pad underneath to blow air into the chassis.. I'm looking for a more elegant solution that solves the problem neatly and thoroughly.
In any case I'll be taking the Tram2 back to DIYHIFI for them to look at. Fortunately I live in Hong Kong, but its still a hassle. The Tram2 is really good when its working so I'm going to miss the music very much!
Incidentally, I'm using VA 2A3 tubes with a 274 rectifier. Have also tried the 5U4 previously but this doesn't seem to make a difference, as I was using the 5U4 when the problem occurred the first time. AC mains voltage in HK is 230V and hence should be spot-on within specification of the pre-amp.
Cheers
HKL
Unfortunately, the right channel of my Tram2 has kicked the bucket again. I bought the TRAM2 as an assembled item from DIYHIFI about 6 months back. I had the same problem about 3 months ago with the same symptoms - i.e. the right channel 2A3 tube wasn't heating up and hence no music. Last time round DIYHIFI informed me the problem was with the heater supply overheating. I'm guessing it is the same problem this time as the symptoms are the same. I've read over the previous posts on this so I'm wondering if anyone else has come across this problem lately, and what solution you've employed to get around this? I think Decky has tried a different type of heatsink and drilled additional holes in the chassis to improve airflow. I'm not keen on installing additional fans or putting a laptop-style pad underneath to blow air into the chassis.. I'm looking for a more elegant solution that solves the problem neatly and thoroughly.
In any case I'll be taking the Tram2 back to DIYHIFI for them to look at. Fortunately I live in Hong Kong, but its still a hassle. The Tram2 is really good when its working so I'm going to miss the music very much!
Incidentally, I'm using VA 2A3 tubes with a 274 rectifier. Have also tried the 5U4 previously but this doesn't seem to make a difference, as I was using the 5U4 when the problem occurred the first time. AC mains voltage in HK is 230V and hence should be spot-on within specification of the pre-amp.
Cheers
HKL
Hi hkl,
The heater supply modules do tend to get really, really hot..! The first pair I had tended to go into low frequency oscillation when they were hot (running 2A3). It seems that in the early Tram II days there was a batch of heatsinks that looked right, but did not perform right, and I had two of those modules. I had the modules replaced by DIY HIFI SUPPLY and have not had problems since. However, the modules are extremely hot..!
My solution has been to add cooling area to the existing heat sinks, but for a more permanent fix I plan to remove the two small heatsinks that are there now and replace them with one larger common heatsink. That way there is room a somewhat bigger heatsink and thus better heat transfer.
The solution with a fan under the Tram II also works fine.
The heater supply modules do tend to get really, really hot..! The first pair I had tended to go into low frequency oscillation when they were hot (running 2A3). It seems that in the early Tram II days there was a batch of heatsinks that looked right, but did not perform right, and I had two of those modules. I had the modules replaced by DIY HIFI SUPPLY and have not had problems since. However, the modules are extremely hot..!
My solution has been to add cooling area to the existing heat sinks, but for a more permanent fix I plan to remove the two small heatsinks that are there now and replace them with one larger common heatsink. That way there is room a somewhat bigger heatsink and thus better heat transfer.
The solution with a fan under the Tram II also works fine.
Desmo
Thanks for your suggestions. I believe I have one of the newer Tram2 pre-amps with the correct heatsinks. I didn't measure the heater supply heatsink temps but yes there were very hot even after turning it off for a while. In any case I've passed the amp to the experts in DIYHIFI to look at. Hope to hear from them soon on what the problem is. At this stage I'm merely speculating that overheating was the problem.
Thanks for your suggestions. I believe I have one of the newer Tram2 pre-amps with the correct heatsinks. I didn't measure the heater supply heatsink temps but yes there were very hot even after turning it off for a while. In any case I've passed the amp to the experts in DIYHIFI to look at. Hope to hear from them soon on what the problem is. At this stage I'm merely speculating that overheating was the problem.
Hi guys,
I have just bought myself the Tram 2 pre and not a fan of LED lights at All and would like to know if its safe to have these removed?
This would include both the selector switch and volume LEDs as well as all the LEDs from the power supply modules underneath the Tram2.
Can anybody help me with this info?
This would be Greatly appreciated.
Thank You.
I have just bought myself the Tram 2 pre and not a fan of LED lights at All and would like to know if its safe to have these removed?
This would include both the selector switch and volume LEDs as well as all the LEDs from the power supply modules underneath the Tram2.
Can anybody help me with this info?
This would be Greatly appreciated.
Thank You.
Hi,
It is not safe to remove all LED's on the PSU Modules, some are used as voltage references on the FCUPS and act in conjunction with their resistors as discharge networks. So you would need to replace them with 3.3V Zenner Diodes.
You can remove those on the Filament Supplies safely.
There is no need to remove the indicator LED's, the information which resistors control the brightness is somewhere in this thread, simply remove these resistors and the LED's will be disabled.
However, I do not understand why you would want to remove the LED's in the first place. These are not multiplexed or PWM controlled (which is where the "LED's are Noisy" story comes from, in fact, LED's are pretty quiet as far as noise goes.
If they are too bright, either change resistors or for those on the powersupplies, simply use a black permanent marker and paint them over...
Ciao T
It is not safe to remove all LED's on the PSU Modules, some are used as voltage references on the FCUPS and act in conjunction with their resistors as discharge networks. So you would need to replace them with 3.3V Zenner Diodes.
You can remove those on the Filament Supplies safely.
There is no need to remove the indicator LED's, the information which resistors control the brightness is somewhere in this thread, simply remove these resistors and the LED's will be disabled.
However, I do not understand why you would want to remove the LED's in the first place. These are not multiplexed or PWM controlled (which is where the "LED's are Noisy" story comes from, in fact, LED's are pretty quiet as far as noise goes.
If they are too bright, either change resistors or for those on the powersupplies, simply use a black permanent marker and paint them over...
Ciao T
Hi,
I just got an assembled Tram2 line stage the other day.
It worked for a day and now I cannot switch channels or regulate the volume. Neither the remote nor the knobs do the trick. The LEDs light up.
I did check for loose connections but nothing obvious (The Tram had a rough ride as a connector had become loose during shipment).
Any suggestions?
Thanks in advance for your help.
Ciao
Joerg
I just got an assembled Tram2 line stage the other day.
It worked for a day and now I cannot switch channels or regulate the volume. Neither the remote nor the knobs do the trick. The LEDs light up.
I did check for loose connections but nothing obvious (The Tram had a rough ride as a connector had become loose during shipment).
Any suggestions?
Thanks in advance for your help.
Ciao
Joerg
Hi,
Check all the front panel connections and see if the rotary encoders took a knock.
Ciao T
Check all the front panel connections and see if the rotary encoders took a knock.
Ciao T
More led questions and 10y substitution.
Thanks guys for your replies and thanks very much Thorsten for answering my question.
I will take out the resistors mentioned to disable the volume and selector led's.
I understand that he main board (at the front of the unit, with the three blue leds in a row are to set the reference voltage and cant be removed.
But the other leds on the other modules can they be removed safely without using zeners???? Or any of the leds.
Would a zener sound better in any of these positions??
Another question: can i use a 10y instead of the 45 tubes and if so how do i reconfigure the unit or change voltages??
Thanks again.
Thanks guys for your replies and thanks very much Thorsten for answering my question.
I will take out the resistors mentioned to disable the volume and selector led's.
I understand that he main board (at the front of the unit, with the three blue leds in a row are to set the reference voltage and cant be removed.
But the other leds on the other modules can they be removed safely without using zeners???? Or any of the leds.
Would a zener sound better in any of these positions??
Another question: can i use a 10y instead of the 45 tubes and if so how do i reconfigure the unit or change voltages??
Thanks again.
Hi guys. Submitted my post before remembering another mod question.
Do you think there may be any improvement using a stepped attenuator (such as the cosmo) over the volume controller the unit comes with??? How good is the supplied volume control???
If this was done what k would the pot have to be??
Thanks all.
Do you think there may be any improvement using a stepped attenuator (such as the cosmo) over the volume controller the unit comes with??? How good is the supplied volume control???
If this was done what k would the pot have to be??
Thanks all.
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