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Philuk 29th April 2012 07:13 PM

Tram2 FCUPS Question
The Tram 2 schematic shows removal of D9 C1 and C2. Is this correct for V2 of the FCUPS board? Also I presume it needs to be set for virtual battery mode?
Any help would be appreciated. Thanks

ptashton 24th May 2012 09:13 AM

I asked Simon from DIY Hifi Supply the same question. Here is his answer:
Hi Peter,

No need to remove for version 2.


> Simon, the Tram 2 Manual V1.34 at page 28 details to remove D9, C1 & C2
> from the Universal Film Cap PSU. Is this required if using the
> Universal
> Film Capacitor PSU Version 2 in the Tram 2. Thanks

ptashton 24th May 2012 09:20 AM

Phil, also don't move the jumpers on J1 and J2. They are set for correct Bias.

I am having all sorts of trouble with my Tram2 FCUPS. Here is what I wrote to Simon to ask the DIY Hifi Supply Technician:

Simon, can you also the technician the following.

When I am doing the post build-up testing and adjustment on the Tram2, I was
able to obtain 2.7 V for the filament supply at step 6 page 24 of the Tram 2
V1.34 Manual. I have 2 10 watt 0.47 ohm resistors in parallel and in
series with the black 5.5 V input wire.

Next I when measured the voltage required at step 8 page 24, I was unable to
obtain -65V (+/-10V). On the Fluke 85 Digital Multimeter, I
obtained -110.7 V on the right Channel and -111.8 V on the left Channel.
During this test and referring to page 18 Step 3 picture detailing voltage

I then inserted the NOS 5U4 rectifier tube and 6AS7 NOS tube into the Tram2
sockets per numbering on the top cover of the pre-amp. I measured 216
Vac-0-216 Vac on the input to the Universal Power Supply Version 2. This
would be because I have 240.5 Vac from the wall socket. On the output of
the universal power supply, I was reading 461 Vdc on the B+ to ABS ground
per requirement of page 25 paragraph 12. It indicates there should only be
250 V and not 461 Vdc. I also read -118 Vdc on the Bias . I should have
220 Vdc on the B= and -74 Vdc on the Bias. There are J1 and J2 jumpers on
the Version 2 Power Supply board. Do they affect the output voltage. I dare
not continue with paragraph 16 to measure 120 V +/-5V.

Nonnegativ 24th June 2012 06:38 PM

Hi ptashton !

Did you ever get a reply from the Technician ? I have a Tram Mk. II that measures more or less the same...

ptashton 26th June 2012 08:41 AM

Response from DIYHIFI Supply
I realise it takes a long time to change offices. The pre-amp is working fine, but I can not get the voltages per Tram2 manual. Maybe Thorsten Loesch can help. Below is the e-mail thread to Simon regarding my out of limit voltage readings.

Response from Simon:

We are moving office from 8th to 13th June 2012. We will reply you as soon as we can. If we reply late, please don't worry, we don't ignore you but just need a bit longer time to reply. If the matter is urgent, please put "urgent" in the subject so that we will give it the priority.

Our new office location:

Simon, any updates on the red LED indication I am getting on the Active Bias
Supply Module. I have tried six RCA 45 tubes which were all checked
serviceable on an AVO Mk 4 tube tester and the Active Bias Supply Module
still showed a red LED on the DS4.


-----Original Message-----
Sent: Monday, May 28, 2012 8:56 PM
To: Simon
Subject: Re: [Feedback] Tram 2 question

Simon, thank you for your reply. The pre-amp is working fine with sound
from both channels. Nice and clear.

Looking at the V1.35 Tram2 manual at page 17, when the pre-amp is powered, I
am getting a bright red LED (DS4) on the right middle side of the Active
Bias Supply Module and a bright blue LED (DS3) on the left middle side of
the Active Bias Supply Module. See attached picture (IMG_5444.JPG) . I
am measuring 9 volts AC from the power transformer to power the module.
The both tubes measure 120 volts between ground and the DHT Anode. I
swapped the new Full Music 45 to see whether the DS4 LED indication would go
blue and the DS3 LED would go red. The DS4 LED stayed red and the DS3 stayed blue. There is continuity between the soldered connections and the
wires. There are no dry solder joints on the Active Bias Supply Module. I am still measuring -117 volts on the Bias supply from the FCUPS.

Is there something wrong with the Active Bias Supply Module. Please consult
your Technician for an answer and please e-mail me.

Thanks again.


ptashton 6th July 2012 12:43 AM

I have sent the FCUPS and ABS back to Simon for test and warranty exchange. Most of the voltages were not in limits per the post assembly adjustment. The 45 heater voltage and final bias voltage were in limits. 2.5 volts at the 45 tubes and 120 volts between the ground and DHT anode.


PixelPlay 11th September 2013 04:36 AM

Was the version 1 fcups board ever sorted as I have the same schematic and am hoping that the component values are correct.

Please help...........


ptashton 12th September 2013 10:36 PM

Greg, I have the Version 2 FCUPS. -117 volts for the Bias supply from the FCUPS is ok. The HT voltage came down from 461 vdc to 250 vdc on it's own.

I wish Thorsten Loesch could give some advice, but I think he has long gone from this forum. Brian is not at DIYHIFI Supply in Hong Kong, as it is left up to Simon who I have met, who I do not think he is technically minded to sort out the problems of their components.

You could ask Lusas Cant from Blackart Audio, to look over the circuit diagram.


beardman 14th September 2013 08:26 AM

If the fcups can not be repaired..then there are other powersupply withs can be used
for the high volt supply ,,there is a Maida regulator : : Audio : 21st Century Maida Regulator

for the bias negative there is a Tentlabs negative bias supply-
Tube bias control

i do not think it is easy to change to the new supply ,,but i think it can be done by a skilled person
best Bjarne

ptashton 14th September 2013 09:40 AM

I hear Thorsten mainly posts at and not on this Forum anymore.

He has recently answered some questions re. diyhifisupply stuff here:

DIYHiFi Forum


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