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dth31 26th June 2011 05:09 PM

Tram 2 45 tubes
 
Greetings! I thought it might be valuable to have, in one place, the newest information about which tubes work well in the the Tram 2.

I must have the "new" TJ45 tubes, as they are totally unusuable due to microphony. I am currently using NOS RCA45's--one is quiet enough, the other is occasionally static-y. When it is being quiet, the Tram 2 is totally awesome. However, I find the intermittent static quite frustrating.

I would prefer NOT to buy 6 NOS 45's in order to try and find 2 that are quiet enough. So question 1: are there any new production 45's that are quiet enough to use? And that sound good?

Question 2: EML tubes. I understand that there are some sort of problems with using EML tubes due to the large size of the EML tube pins. I don't like to roll tubes--I like to put in tubes I like and leave them. If I do that with EML's (assuming they are quiet enough) will they fit into the tube sockets (I don't want to damage either the pins or the tube sockets)? If they stretch the sockets and the sockets then won't fit smaller pin tubes, that's OK with me, as long as the sockets will continue to fit the EML tubes tightly.

Question 3: 2A3 tubes. My Tram 2 was assembled by DIYHifiSupply. While I could adjust the 2A3 bias, I would prefer not to have to check or adjust it. If I decide to try 2A3's in the Tram 2, do I need to check the voltages? Or can I just put the 2A3's in and forget about it?

Question 4: Are there new production 2A3's (EML, Valve Art, Sovtek) that are known to be consistently quiet enough and sound good?

Thanks. I really love the Tram 2 when the 45's are quiet--one could EASILY spend $8-10K and not get better sound. But the noise is a frustrating problem. I hope the answers to the above questions will help to reassure prospective buyers, and current owners, that tube noise is a simple, manageable issue that is not a significant problem!

Dave

ThorstenL 27th June 2011 07:49 AM

Hi,

Quote:

Originally Posted by dth31 (Post 2619873)
I must have the "new" TJ45 tubes, as they are totally unusuable due to microphony.

Microphony is normally low in the TJ 45's, it is hum pickup that causes problems. Which output on the preamp are you using?

Quote:

Originally Posted by dth31 (Post 2619873)
So question 1: are there any new production 45's that are quiet enough to use? And that sound good?

Of what we had a chance to try so far, difficult.

Quote:

Originally Posted by dth31 (Post 2619873)
Question 2: EML tubes. I understand that there are some sort of problems with using EML tubes due to the large size of the EML tube pins. I don't like to roll tubes--I like to put in tubes I like and leave them. If I do that with EML's (assuming they are quiet enough) will they fit into the tube sockets (I don't want to damage either the pins or the tube sockets)? If they stretch the sockets and the sockets then won't fit smaller pin tubes, that's OK with me, as long as the sockets will continue to fit the EML tubes tightly.

The EML we tried where quiet and sounded good, other than issues of pricing and the oversized pins they work well.

Quote:

Originally Posted by dth31 (Post 2619873)
Question 3: 2A3 tubes. My Tram 2 was assembled by DIYHifiSupply. While I could adjust the 2A3 bias, I would prefer not to have to check or adjust it. If I decide to try 2A3's in the Tram 2, do I need to check the voltages? Or can I just put the 2A3's in and forget about it?

Normally Plug/Play works, but it is worthwhile checking the voltages and if necessary adjusting them.

Quote:

Originally Posted by dth31 (Post 2619873)
Question 4: Are there new production 2A3's (EML, Valve Art, Sovtek) that are known to be consistently quiet enough and sound good?

Valve Art and EML are tested, both good. Older TJ 2A3 as well, not sure about current.

Ciao T

dth31 27th June 2011 01:31 PM

Thorsten said:
"Microphony is normally low in the TJ 45's, it is hum pickup that causes problems. Which output on the preamp are you using?"

I have tried all 3. I am using the -3dB output now with the LD91 Mono Max and Bastanis Prometheus II open baffle speakers. This results in having the volume control at about 10-11 o'clock (I listen pretty loud).

It's also definitely microphony--if I speak at the tubes, my voice comes out of the speaker.



Thanks Thorsten. I think I'll try the EML45's. I think this preamp deserves the best!

clivetjm 27th June 2011 02:20 PM

What damping do you have on the tubes? I suspect any new production tubes will need some form of damping.

dth31 27th June 2011 02:44 PM

Quote:

Originally Posted by clivetjm (Post 2620788)
What damping do you have on the tubes? I suspect any new production tubes will need some form of damping.

Excellent question. I have dampers on all of the tubes. On the 45's, I've tried various types of Herbies dampers, including teflon and metal-ring types. I've also tried various combinations of dampers and teflon tape. This seems to work fine on the NOS 45's, but nothing helped the TJ45's. In addition to the microphony, the inner metal structure periodically (every few minutes) literally rings like a gong. It's worse right after I turn on the preamp and I guess the tube warms up and the metal expands.

Dave

beardman 27th June 2011 06:15 PM

Hej
i use now JJ2A3 40 TUBES----sound good and very low microfonic--no hum-little hiss

bjarne

ThorstenL 28th June 2011 06:33 AM

Hi,

Quote:

Originally Posted by dth31 (Post 2620748)
I have tried all 3. I am using the -3dB output now with the LD91 Mono Max and Bastanis Prometheus II open baffle speakers. This results in having the volume control at about 10-11 o'clock (I listen pretty loud).

That is probably way too much gain for the system. I would suggest to try the lower output, I would suggest maximum listening levels should be closer to 3-o'Clock. 10 to 11 o'Clock does not really leave much volume control range.

Quote:

Originally Posted by dth31 (Post 2620748)
It's also definitely microphony--if I speak at the tubes, my voice comes out of the speaker.

Yes, all DHT's do that to a degree. It is even audible in Power Amplifier Output Stages, where the gain is typically 30dB lower than for a linestage.

You can try some ways of damping.

Ciao T

clivetjm 28th June 2011 08:24 AM

Do try the lowest output option. I use LD91 and Bastanis Atlas with the lowest output option. My high-level listening is with the volume at around 3 o'clock. I never need to exceed max volume on the Tram with this setting.

bronal 3rd July 2011 07:38 AM

Hello everyone:
For my sins I own TWO Trams. I am running one with 45s and the other with 2A3s. I agree 100% with dth31's findings - TJ 45s are highly microphonic and more or less useless. NOS NU 45s I got from Brent Jessee are not microphonic at all but do splutter a bit at turn-on and then settle down after a few minutes. I believe these were in fact made by RCA and then rebadged for various other companies. I am currently running EMLs, which are slightly microphonic, but nothing to write home about. Beautifully made and have a wonderful tone as well.

On to the other valves: I'm using a Chelmer brand UK 5U4G rectifier in one Tram and a straight-sided Australian Radiotron. (Hint: if you see NOS Australian valves, buy them - they were made in Mullard factories for GE or Philips and are the equal of any UK, US or Euro valve - and usually a lot cheaper too!)

6AS7s: Sylvania in one Tram and GE in the other.

dth31 3rd July 2011 06:08 PM

I ordered some of the EML 45s this week, as well as some different 6AS7's. I'll report back once I've had a chance to test them.


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