DHT OTL Linestage - Tram 2

[marybety]

Well it seems I have found the problem. There were no connection between CCS and Anode pin of the triodes. Yes, my fault. I am very sorry if someone couldnt sleep because of that.

B+ voltage at FCUPS is now 240V
But now I am getting 27V between anode pin of the triodes. It should be 120V. I ve been trying to adjust with the potis but the change is minimum.

Any ideas??

[ptashton]

marybety, recheck you have assembled your CCS circuit boards correctly with the correct resistor values. Recheck all your connections per Tram2 manual and ensure you are measuring at the correct test points. See how that goes.

Peter

[marybety]

Hello Peter
as per your recommendation, I have checked and measured the CCS resistors. Well, one of the 6.8K kiwame resistors is actually a 0.68K resistor!! or may be it is broken. How could that happen????
I guess it should behave better after replacing it. Now I have to wait a couple of days as kiwame nor takman are to find in Germany.
Thanks again for your recommendations.
Regards
Marybety

[Desmo]

I was asked these questions by pb and thought that I would share the answers with all of you:

I just wanted to ask you, which ones of all the tuning tweaks performed were in your opinion the most noticeable?
or which one would you recommend to start with?

The Rod Coleman DHT regulators gives -by far- the biggest improvement in sound. Actually I consider the sonic improvement from these regulators bigger than all other upgrades combined.

I would also start with the DHT regulators since implementing them takes some structural work and that is much easier to do when building the preamp than after.

[ptashton]

Morten, do you have any drawings of the DHT regulator aluminium brackets and heatsinks to share with the forum.

Still waiting on the RCA single plate 2A3 tubes.

I am looking at Philips and Marantz CDM1 laser drives with TDA1541A DACs. I heard a setup and the CD player which was so smooth with the Tram2 pre-amp.

Any experience from the forum on these CD players with the Tram2.

[Desmo]

Sorry, no drawings... But look at the pictures, and I'm sure you can make something similar. I have just used regular hand tools to make it, so no special tools or anything like that is needed.

[GeirT]

Hi Morten,
Finally got to order power supply parts at Farnell (UK methink) for the Coleman DHT regulators. However, it didn't seem they had the Mills resistors nor the Amtrans caps. If you have any recommendation of a supplier it would be very nice to get a hint :-)

Other issue; as I have a defunct volume controller in my Tram 2, I bypassed the whole input selection anf attenuator board and used a TVC (Sowter model 9335 w/OCC wiring) as volume attenuator. The Tram is a really nice and transparent tubed buffer-stage! :-D

Geir

[clivetjm]

Hi Geir,

Have you configured the TVC on the Tram output? Up to 6db gain availavle like this with the TVC attenuating any noise or hum. Easy load for souces too.

[Desmo]

Originally Posted by GeirT

Hi Morten,
Finally got to order power supply parts at Farnell (UK methink) for the Coleman DHT regulators. However, it didn't seem they had the Mills resistors nor the Amtrans caps. If you have any recommendation of a supplier it would be very nice to get a hint :-)

Other issue; as I have a defunct volume controller in my Tram 2, I bypassed the whole input selection anf attenuator board and used a TVC (Sowter model 9335 w/OCC wiring) as volume attenuator. The Tram is a really nice and transparent tubed buffer-stage! :-D

Geir

Hi Geir,

The electronic suppliers usually don't have the audio products, but here are some good sellers that I normally buy parts from:

Parts ConneXion - The authority on hi-fi DIY parts and components
Acoustic-Dimension, high-end audio and components for tube audio
amplifier valve kits, HIFI pre-amplifiers, speaker kits,AMP Parts, upgrade components

Regarding the volume, then you should of course be able to get a replacement under warranty if it does not work..!?

As Clive mentions, a TVC on the output is an interesting solution, have you then omitted the resistor network on the output?

[GeirT]

Thank you a lot Morten!
Concerning the defunct attenuator, Simon at Diyhifisupply has already responded positively to replace the control board.

I currently use the TVC in front of the preamp as it gives me the opprtunity to connect balanced sources (XLR) as my RIAA and Weiss DAC which both sounds significantly better using their balanced outputs.
I must say the sound in this set-up is perversely good ;-)

I've not used the TVC after the pre but should be easy to try.

Geir