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-   -   DHT OTL Linestage - Tram 2 (http://www.diyaudio.com/forums/diy-hifi-supply/156854-dht-otl-linestage-tram-2-a.html)

bcherry 16th December 2009 07:33 AM

DHT OTL Linestage - Tram 2
 
1 Attachment(s)
What do DHT (direct heated triodes) REALLY sound like? Yes we've heard VT25, 45, 2A3, 205d, 300B etc in many an amplifier, enshrouded by driver tubes and output transformers. And we can plainly hear the differences between DHT types in that context, tainted though the sound must be with so many extraneous elements.
The only way to really hear the sound though is to go spud. And what better place to do that than right at the beginning - the linestage. Many will say that the linestage contributes more than the amplifier, so...

UX4 sockets: this would allow 10/10Y/VT25, 26, 45, 71A, 2A3, 801A/VT62, 300B, 101D, 205D if we can design in enough control to supply the variety of filament, and B+ voltages needed. Used spud we'd have a friendly gain structure of between 9 and 18db. Most have lowish anode impedance; no transformer needed as in the range ideally suited for preamp duty. So...OTL it is!

With adjustable CCS for the anode we can control the anode current. Easy done.

Since this is an all-out attempt to hear the real DHT, and all of it, we don't want un-necessary caps in the signal path. So let's go fixed bias, thus avoiding the cathode bypass cap. To make this easy we have our ABS module feeding the grid which can be set with one resistor for the desired operating point.

Power supply: to stay with the theme lets use a DH rectifier tube.

We don't want ANY electrolytic caps blowing smog into our sonic landscape so we will let the all film-cap FCUPS module provide the P:USH power we need. This has the added advantage of supplying the bias voltage needed by the ABS and bonus: jumper setting for virtual battery or virtual choke operation. And it is super quiet.

The filament supply also needs to be quiet, be a brick wall to the signal (DHT, remember?) and be adjustable: DIYHFS filament supply just happens to be on our shelf.

Transformer noise will be an issue so let's order a potted (3mm steel) torroid which has the advantage of radiating EMF axially thus avoiding noise in the chassis. Our goal is to do this all on one chassis. We'll mount tx forward, to keep it away from the signal end of the chassis.

We'll need one pair of 2.2uf/250v coupling caps for output and 1 pair 0.1uf on the input grid.

Chassis will be the Projekt Box, also at hand.

Layout will look something like the attached.

Here we go!

camotecue 1st February 2010 05:39 AM

follow-up
 
how did the project go?

bcherry 2nd February 2010 03:00 AM

DHT OTL Linestage - Tram 2 - Update
 
http://diyhifisupply.com/files/images/TramAlls.jpg

I'm getting quite a few emails asking for updates on the Tram2:
We're pretty well there. The current design will grow one more tube, a 6AS7. This will allow us to expand the range of DHT that can be used without major circuit changes. As seen here we can change 2A3 and 45 on the fly.

Microphonics was a big problem early on but this has been solved using floppy tube socket mounting and selectable output gain, 12, 3 and -6db gain, as well as a few other tricks. I think most tubes can be used. The first build could only use a pair of NOS 45's we have. With all others it was the Gong Show. All the new manufacture 2a3/45's have much larger glass bodies than NOS and support the filament with spring tension and so ring like Big Ben at noon. The Shuguang 2A3 were the worst - looks like pen springs used. But now we are able to use every tube we've tried - about 8 different types including Shuguang, TJ, and NOS types.

Also selectable ouput gain means linestage gain can be matched to speaker efficiency.

You can see we've made good use of the Technology Bites Series of modules we sell.
Noise was solved using a very low noise filament supply implementation.

We've used the ABS (auto bias system) to safely exploit the benefits of fixed bias. This allows getting rid of the cathode capacitor and using a single low value, high quality resistor on the cathode. At the linestage level, these design touches are very noticeable, more so than down the signal chain.

The FCUPS (Film Cap Universal Power Supply) supplies the DHT B+ which also uses a CCS for the anode load. This might seem like overkill for a linestage but if we want a big sound we need big tubes and big power supply. The FCUPS does everything the original Tram regulated power supply did -- and more. The DIYHFS theme song is: No Electrolytics! so we use film caps as much as possible.

The for sale version of the Tram2 will have an option for the UVC (Universal Remote Control) with 126 steps and 6 inputs (if we can find enough space on the back panel).

So what are we waiting for?
Transformers. Soon as we get them in stock we will do the build, shoot the pics for the manual and list them. Price to be fixed later when all costs are in.

Oh yeah, the sound: This is No Sacrifice Sound. The last 7 years I've gone back and forth between TVC and active; each has its merits. But the Tram2 does it all. Huge dynamics with all the inner detail and transparency of TVC.

This is The One!

regards
Brian

bcherry 9th April 2010 05:10 AM

Wham! Bam! it's the Tram 2 - DHT OTL Linestage
 
1 Attachment(s)
It's done!

The guided tour:

Back: 2 tubes are the Direct Heated Triodes - 2A3 or 45 plug and playable without any circuit changes.
Middle: left tube is the Super Mu 6AS7 and right is the 5U4 rectifier

The tube sockets are mounted in a subplate which is compliantly mounted to the chassis. Rapping on the chassis produces no audible feedback.

Front: the power transformer. From our 98db speakers we can hear just a little tube rush from the 2A3. No hum.

Front panel: Remote controlled selector then power switch left, 120 step volume control on the right. Selector has 5 inputs (also additional inputs for REC on back panel)

Back panel: 6 prs RCA inputs and 3 prs outputs, +6, 0, -6db (this can be changed internally) for system matching which is absolutely necessary to marry DHT and high efficiency speakers.

Inside the chassis: Will post pics next report but power supply is FCUPS and all film cap (big L small c). Ultra Low noise Filament Supplies on the 2A3/45. Auto bias Supply controls the DHT. Etc Etc.

On the bench we get extremely linear and low distortion test results.

OK more later.

bcherry 12th April 2010 05:08 AM

Bottom View
 
2 Attachment(s)
The concept couldn't be more simple: Use direct heated triodes for linestage duty. Put some signal on the grid, heat the cathode, add B+ to the anode and voila! What could be easier? Works for DHT amplifiers, and parts count is low.But put a DHT into a linestage where signal levels are in the mv range and we crash into noise, microphonics, noise, possible impedance issues and more noise.


Noise can come from power transformer, filament supply, B+, poor grounding, bad layout, not to mention proximity to outside sources of noise.


The Tram 2 starts with good layout. We wanted a single chassis solution together with power transformer. So transformer at the front, triodes at the back close to input/output connections. Tube rectifier and 6AS7 closest to the transformer.

B+ is supplied from the ultra low noise film cap power supply module and the cathode supply comes from our filament supply module with added capacitance.


Microphonics must be the middle name of the triode family. We already encounter this in amplifier position, but in a linestage -- talk to your triodes and maybe your speaker talks to you! All slight to jarring level vibrations will mess up the clarity of the sound. Everything around us resonates and thus vibrates.

The Tram 2 mounts the triodes on the 3mm tube subplate which is in turn mounted to the chassis with compliant isomount standoffs. Knuckle rap on the chassis doesn't transfer so we've done well.

The other factor is system gain. High sensitivity amplifiers and speakers will feedback through the tubes and exacerbate microphonics. So we have provisioned 3 outputs: +6db, -3db and -12db. The user needs to select in system but in general: amplifiers with input sensitivity of 2 to 6v would match +6db outputs; 0.7v - 2v amps: -3db outputs; below 0.7v amps: -12db outputs.


Of course this impacts on impedance so it requires finesse. The Tram 2 can comfortably handle amplifier loads down to 2k ohms.


Result: through our in-house Crescendo speaker system, 98db/w (100db/2.83v/1m in room) we get no hum, just a little tube rush.
We'd originally planned to use a choke to load the anode of the triode but that would push us to a 2 chassis linestage and potentially more noise pickup. So we instead used a 6AS7 together with CCS to load the anode. Result is very low output impedance and very high anode load. The effect is as a super mu follower.


Why DHT OTL linestage?
DHT sound better. On the test bench we get very low noise and very low distortion. What little distortion is there, is of the single ended type which many feel to be consonant with the sound of music.

The Tram 2 as presented can use either 45 or 2a3 types. With some tweeking to the circuit 26, 71, 27 and 56 (non-DHT) can also be used.

One thing to note: as with a formula class racing car, with a DHT linestage we are going for ultimate performance and so give up a few niceties. Care needs to be taken to place the Tram 2 away from noise sources from other gear such as big torroids.

Tube selection is important. NOS and ST types generally have less microphonics. We've tried with NOS 45/2A3, TJ meshplate 45/2a3 and carbon/meshplate plate globe types and Valve Art 2A3 single and double plate. Overall the ST types were less noisy. The big globes tend to be more microphonic; ditto for some of the new production types with coil spring tensioners for the grid wire.


What you get is very low distortion, linear output with all the tonality offered by direct heated triodes as close to the source as possible.

DIY - Done Right!

bcherry 12th April 2010 01:08 PM

On the Bench
 
Frequency response: better than 0.5dB 20Hz - 20KHz
S/N Ratio: > 93dBA
THD & N: < 0.2%

All measurements referenced to +18dBu (6V), +10dBu (2.45V) and +2dBu (1V) for the respective outputs
All measurements taken with Sovtek 2A3 and vary with tubes employed

julianr 15th April 2010 10:58 PM

Hi I have been reading your updates and am thinking about building this. I use bastanis open baffles and run the sub woofer off my current pre out - would this be possible with this amp i.e. can I take a parallel output.

Julian

bcherry 16th April 2010 04:59 AM

Quote:

Originally Posted by julianr (Post 2155041)
Hi I have been reading your updates and am thinking about building this. I use bastanis open baffles and run the sub woofer off my current pre out - would this be possible with this amp i.e. can I take a parallel output.

Julian

Depends on the paralleled impedances of the sub amp and the amplifier. For example if each was 50k then the net load in 25k.
The Tram 2 can comfortably drive loads down to 2kohm

Have you tried driving the subamp from the speaker out of the amp through a dropping resistor into the low level inputs of the subamp> When we had the Prometheus we found it gave the best sound. Also that way the subs see exactly the same signal as the main speakers, and impedance is no longer an issue.

julianr 16th April 2010 07:54 AM

I have not tried driving the subamps that way - i will think aout it. My preamp (home made) has 2 outputs, one essentially an anode and one a cathode follower - this seems to drive the speakers well.

thanks for the reply.

bcherry 2nd August 2010 05:34 AM

Grand Slam for the Tram2
 
1 Attachment(s)
Enjoythemusic has just posted the world's first review of the Tram2.


This was a very well conducted review. The reviewer understood exactly the point of a DHT linestage its care and feeding. Please note the 'Fettling Guide'
Have a read here


We've finally sourced a compact remote control which we will program and make available as an option.


Some notes about tubes: NOS sound rich but difficult to get a pair quiet enough for linestage use. With the Herbie guitar dampers, Tj and other modern production 2A3/45 can be used. Note re EML that tube pins 2/3 are oversized compared to NOS spec and will damage teflon tube socket pins grippers. We have both EML 2a3 and 45 here and that is our experience.

xerocomm 2nd August 2010 07:17 PM

Tram2
 
We are one of the US dealers for DIY HiFi Supply and I must say Brian has given the new meaning to absolute perfection. This DHT OTL Preamplifier is one of the finest sounding pieces that is priced under $10,000, maybe $14,000 and when I found that DIY HiFi Supply set it's retail price at $1395 I was shocked and impressed at the same time. We carry over 30 different brands, mostly high end and the Diy HiFi Supply Tram Mk2 DHT OTL Preamplifier has taken the top spot in our showroom.:D

We had a few problems in the beginning all of which was our fault :spin:, once we got past the issues, we fired up the Tram2. Wow, this has brought our current amps and speakers to a new level. Enjoy the Music.com said it best "Is Tram Mk2 the best preamp in the world? I can't answer that, but I'm sure it would not disgrace itself against any preamplifier....." I complete concur.

If you buy the kit, please post any issues, although the DIY HiFi Support is top notch, so you will probably not need to past the questions here. Either way, I would love to hear your comments or see a build thread.

Chris
Xerocomm Audio

xerocomm 2nd August 2010 07:27 PM

Quote:

Originally Posted by julianr (Post 2155041)
Hi I have been reading your updates and am thinking about building this. I use bastanis open baffles and run the sub woofer off my current pre out - would this be possible with this amp i.e. can I take a parallel output.

Julian

Julian,

We are one of the US dealers for DIY HiFi Supply and Bastanis. I tested the Tram Mk2 using the Bastanis XTZ Sub Amp 1 DSP with a DIY HiFi Supply LD91. I was able to hook up the amplifiers using the current outputs on the Tram2 and then adjusted the XTZ Sub. We also tested the impedance and it was not close to the max rated by DIY HiFi Supply.

julianr 2nd August 2010 09:55 PM

Chris - thanks for your insight - I will seriously consider building this, need to justify the cost!

bcherry 3rd August 2010 07:39 AM

Quote:

Originally Posted by xerocomm (Post 2260935)

If you buy the kit, please post any issues, although the DIY HiFi Support is top notch, so you will probably not need to past the questions here. Either way, I would love to hear your comments or see a build thread.

Chris
Xerocomm Audio

So would we at DIYHFS so please DO post the questions here so the DIY community can benefit. Patterns emerge that can help us with refinements. Also the same mistakes are often repeated.

thanks
Brian

tullskull 3rd August 2010 10:34 PM

Congrats on the great review Brian. Very nice read and I am happy for you.
Hope we will start seeing some feedback on the new speakers soon.

bcherry 4th August 2010 02:34 AM

Quote:

Originally Posted by tullskull (Post 2262118)
Congrats on the great review Brian. Very nice read and I am happy for you.
Hope we will start seeing some feedback on the new speakers soon.

Thanks. We haven't lined up a reviewer for the Crescendo yet. When we get a few more out there i;ll try to collect some user comments and post it.

regards
Brian

clivetjm 10th August 2010 02:27 PM

Quote:

Originally Posted by julianr (Post 2261070)
Chris - thanks for your insight - I will seriously consider building this, need to justify the cost!

Julian, where are you in the UK? Maybe you can have a listen here (Cheshire).

julianr 10th August 2010 05:59 PM

I am in Halifax so not a million miles away, have you diy'd it?

clivetjm 10th August 2010 07:15 PM

Quote:

Originally Posted by julianr (Post 2268632)
I am in Halifax so not a million miles away, have you diy'd it?

Hi Julian,

This time around I didn't diy. If you've read the article you know what I have here....

xerocomm 10th August 2010 09:17 PM

Quote:

Originally Posted by julianr (Post 2268632)
I am in Halifax so not a million miles away, have you diy'd it?

Julianr, As a last resort I can always send you my Tram2 to demo from the US. I would require a refundable deposit but I would be willing to offer this option if you find it hard to get to someone local. I just wanted to throw out this offer. PM me if this helps.

xerocomm 10th August 2010 09:21 PM

Quote:

Originally Posted by julianr (Post 2261070)
Chris - thanks for your insight - I will seriously consider building this, need to justify the cost!

Julianr, Either way try to get a demo established. The Tram2 is worth every penny, although this is ONLY my opinion - your tastes may be different. Let us know if we can support you in any way. If you have not worked with (assembled) the DIY HiFi Supply products, you are in for a plesent surprise.

clivetjm 10th August 2010 09:23 PM

Julian, I'm in Bowdon (Altrincham), 50 miles via the M62. Due to holidays and work travel I won't be around until the end of the month. There's always bank holiday weekend.

xerocomm 10th August 2010 09:35 PM

Quote:

Originally Posted by julianr (Post 2268632)
I am in Halifax so not a million miles away, have you diy'd it?

Looks like you have many options. Sounds like clivetjm is at your backdoor. If that does not work out, let us know. We ship daily to the UK (Audio Note), so we could slip in an extra box for little $$$.

julianr 10th August 2010 10:01 PM

xerocomm thanks for your kind offers, I think I should try and hear before buying and should manage to arrange something over here as clive is not far away.

clivetjm - sorry I did not make the connection with the review. I would like to try and hear the tram, I will check my work schedule but I think I am free most of the bank holiday weekend - that is if she who must be obeyed has not arranged anything. What would be good for you.

clivetjm 10th August 2010 10:04 PM

Sending a PM....

julianr 10th August 2010 10:05 PM

thanks

xerocomm 10th August 2010 10:10 PM

Quote:

Originally Posted by julianr (Post 2268898)
xerocomm thanks for your kind offers, I think I should try and hear before buying and should manage to arrange something over here as clive is not far away.

clivetjm - sorry I did not make the connection with the review. I would like to try and hear the tram, I will check my work schedule but I think I am free most of the bank holiday weekend - that is if she who must be obeyed has not arranged anything. What would be good for you.

No problem, makes sense - just wanted to open the door. Let me know if you need anything or if you would like a quote on the Tram2.

xerocomm 11th August 2010 06:34 PM

Quote:

Originally Posted by bcherry (Post 2260460)
Enjoythemusic has just posted the world's first review of the Tram2.


This was a very well conducted review. The reviewer understood exactly the point of a DHT linestage its care and feeding. Please note the 'Fettling Guide'
Have a read here


We've finally sourced a compact remote control which we will program and make available as an option.


Some notes about tubes: NOS sound rich but difficult to get a pair quiet enough for linestage use. With the Herbie guitar dampers, Tj and other modern production 2A3/45 can be used. Note re EML that tube pins 2/3 are oversized compared to NOS spec and will damage teflon tube socket pins grippers. We have both EML 2a3 and 45 here and that is our experience.

Brian,

What is the retail cost on the remote? When can we order it?

bcherry 12th August 2010 03:46 AM

Cost is 25USD.
I expect delivery next week.
Brian

JimU 15th August 2010 06:03 PM

Sizzling.
 
Hi, The repetitive sizzling mentioned in the EnjoyTheMusic review could be some instability in the PS/CCS, will this be investigated? Tnx, Jim

xerocomm 15th August 2010 09:06 PM

Quote:

Originally Posted by bcherry (Post 2270195)
Cost is 25USD.
I expect delivery next week.
Brian

Brian, Great job and great price, thanks.

bcherry 20th August 2010 12:59 AM

Quote:

Originally Posted by JimU (Post 2273701)
Hi, The repetitive sizzling mentioned in the EnjoyTheMusic review could be some instability in the PS/CCS, will this be investigated? Tnx, Jim

It's not. Everything is regulated and clean. It seems to be related to the tubes, especially older tubes. It also seems to diminish as the tube is used, maybe dissipating traces of gas on older tubes or stabilizing cathode emissions. We think these are sounds that were always there but masked in amplifier applications.

regards
Brian

delicious2 30th August 2010 08:10 PM

Quote:

Originally Posted by bcherry (Post 2277997)
It's not. Everything is regulated and clean. It seems to be related to the tubes, especially older tubes. It also seems to diminish as the tube is used, maybe dissipating traces of gas on older tubes or stabilizing cathode emissions. We think these are sounds that were always there but masked in amplifier applications.

regards
Brian


When I moved to my new home in a different town 3 years ago my VTL TinyTriodes Signature Ed. which had been quiet and stable for all of their 8 years began blowing tubes at startup with associated popping and sizzling before a valve would go nova. I put it down just to old tubes and time to get things retubed and rebiased so back to VTL they went. Turned out it wasn't that simple and they have to be on a good filtering powerstrip (Furman in this case) in this house. The whole system is on that power filter at the moment. Could the quality of power coming in affect the Tram 2 despite its internal regulation?

BTW, This is my first post. I joined this forum after reading the EnjoyTheMusic review and would be very interested in having a demo in my home in Massachusetts. The Tram 2 would replace a Parasound SS preamp to the VTLs to Klipschorns in my 22 x 13 x 8 living room.

peace,
Mark H

bcherry 1st September 2010 02:19 AM

Quote:

Originally Posted by delicious2 (Post 2288505)
When I moved to my new home in a different town 3 years ago my VTL TinyTriodes Signature Ed. which had been quiet and stable for all of their 8 years began blowing tubes at startup with associated popping and sizzling before a valve would go nova. I put it down just to old tubes and time to get things retubed and rebiased so back to VTL they went. Turned out it wasn't that simple and they have to be on a good filtering powerstrip (Furman in this case) in this house. The whole system is on that power filter at the moment. Could the quality of power coming in affect the Tram 2 despite its internal regulation?

BTW, This is my first post. I joined this forum after reading the EnjoyTheMusic review and would be very interested in having a demo in my home in Massachusetts. The Tram 2 would replace a Parasound SS preamp to the VTLs to Klipschorns in my 22 x 13 x 8 living room.

peace,
Mark H

Welcome!

There are many variables so anything is possible. However in this case it seems the effect follows certain tubes.

Not sure about the home demo. You can email me.

regards
Brian

bcherry 1st September 2010 02:23 AM

Blue Note Award for the Tram2 - Wow!
 
1 Attachment(s)
This is a great way to kick off the new business year -- Enjoythemusic.com Blue Note award for the Tram2. Credit to Enjoythemusic.com staff for putting aside the unsaid selling price hierarchy and awarding the Blue Note on performance alone.
That's integrity.

delicious2 2nd September 2010 05:32 PM

Congratulations!
 
:cheers:

clivetjm 12th September 2010 11:08 AM

Quote:

Originally Posted by bcherry (Post 2277997)
It's not. Everything is regulated and clean. It seems to be related to the tubes, especially older tubes. It also seems to diminish as the tube is used, maybe dissipating traces of gas on older tubes or stabilizing cathode emissions. We think these are sounds that were always there but masked in amplifier applications.

regards
Brian

I'd like to back up what Brian has said about the sizzling sounds. Since the review I've continued to swap my tubes around. The 1930's / 1940's 45s I have are very used....the previously unusable pair after a few hours of being powered up have become usable. With both pairs of ancient 45s I've found the sizzling has greatly subsided and all but gone after leaving them powered up all day. Sometimes on power up it comes back but it soon goes. I have no doubt this is some form of internal issue in these very old and very used tubes.

2bkurious 26th September 2010 04:53 PM

Tube selection
 
If one were seeking neutrality which would be the better tube 2A3,45?

catastrofe 26th September 2010 09:12 PM

Any estimate of tube life on the triodes? Especially if they're left on 24/7?

clivetjm 28th September 2010 09:58 AM

My comment above about leaving the tubes on all day was about leaving them on all day but just for one day! Not everyday. Sorry for being misleading.

I've since (at last) worked out that even though the NOS tubes pins looked clean, they weren't. Most, if not all the noise was due to this and these tubes depositing some crud into the sockets.

Which is better? 45 or 2A3? I have some fabulous truly NOS 2A3 that are sounding great. Hard to say which tubes intrinsically are better, probably whichever tube is in better condition and the least microphonic.

otto88 25th October 2010 05:10 PM

Hi Brian
I have some 2a3s and 45s, but I'd like to run this with the 01-A. Thoriated tungsten filaments, more gain, etc.
The filaments need 5 V. 0.5 A, and B+ is 135.

And the 71A: same filament supply; max B+ is 180, but 135 should be ok

How much would you charge on top of an assembled amp, to set it up for them?

beardman 25th October 2010 07:57 PM

Tram 2 ,best i ever had
 
Like to tell a little about my Tram 2 pre---the sound is the best i have had in my system---it had the feeling that you are in the music--this i have not heard before---the review by enjoy music is just right--so i am very happy by the result---
i have make some hum and microfonic damper-----2 big iron tube--one over each 45 tube--
and a wire from the iron to shield on the input---this had removed all hum--and less crackling on start---les microfonic--
the iron tube is 10cm ---15cm high---5mm thick--
if someone like it---i can tell about what i have compared,the Tram 2 with--
thanks to Diyhifi-supply for good service---(Simon)

sorry my bad english--
Bjarne
from Denmark

otto88 25th October 2010 10:56 PM

Hi
What are the differences, both technical and sonic, from the original Tram W.O.T.?

clivetjm 26th October 2010 09:05 AM

Quote:

Originally Posted by otto88 (Post 2343717)
Hi
What are the differences, both technical and sonic, from the original Tram W.O.T.?

I've not heard the original Tram WOT but I do know that WOT means "With Output Transformer", the mkII does not have an OPT. The mkII is a totally new preamp, sharing nothing with the WOT. The diyhifisupply site has details and link to the review of the mkII.

clivetjm 26th October 2010 09:09 AM

Quote:

Originally Posted by beardman (Post 2343585)
Like to tell a little about my Tram 2 pre---the sound is the best i have had in my system---it had the feeling that you are in the music--this i have not heard before---the review by enjoy music is just right--so i am very happy by the result---
i have make some hum and microfonic damper-----2 big iron tube--one over each 45 tube--
and a wire from the iron to shield on the input---this had removed all hum--and less crackling on start---les microfonic--
the iron tube is 10cm ---15cm high---5mm thick--
if someone like it---i can tell about what i have compared,the Tram 2 with--
thanks to Diyhifi-supply for good service---(Simon)

sorry my bad english--
Bjarne
from Denmark

Sounds like a good solution as the 45s don't get particularly hot. The Tram mkII does sound really great doesn't it! :)

beardman 26th October 2010 09:21 AM

Hello Clivetjm
The tram 2 have a sound ,that could be hard to understand--i have before that-a Aikido-a pass lab x02---conrad johnson act 2--but the tram2 is just more what music is about--
bjarne

otto88 26th October 2010 01:37 PM

"The diyhifisupply site has details and link to the review of the mkII"

Yes, I've read all that

"original Tram WOT but I do know that WOT means "With Output Transformer", the mkII does not have an OPT. The mkII is a totally new preamp, sharing nothing with the WOT"

So they are both relatively unique in being WOT. How do you know it is *totally new?

clivetjm 26th October 2010 02:30 PM

Quote:

Originally Posted by otto88 (Post 2344308)
"The diyhifisupply site has details and link to the review of the mkII"

Yes, I've read all that

"original Tram WOT but I do know that WOT means "With Output Transformer", the mkII does not have an OPT. The mkII is a totally new preamp, sharing nothing with the WOT"

So they are both relatively unique in being WOT. How do you know it is *totally new?

They are not both WOT. The mkI has OPTs, the mkII does not. The mkI used 5687 whereas the mkII uses 2A3 / 45, it uses the DIYHS heater modules, Active Bias module, Ultimate Volume Control Module, Universal all Film Capacitor Power Supply.....I don't believe these modules existed when the mkI was around. Like I said, totally new.

cjunkk 2nd November 2010 09:34 AM

Quote:

Originally Posted by beardman (Post 2343585)
i have make some hum and microfonic damper-----2 big iron tube--one over each 45 tube--
and a wire from the iron to shield on the input---this had removed all hum--and less crackling on start---les microfonic--
the iron tube is 10cm ---15cm high---5mm thick--

Hello,
could you please post a picture of the iron tube dampers?

Carlo

beardman 2nd November 2010 10:30 PM

Hej Carlo
i dont now how to upload picture---i could perhaps send it on mail to you---
the iron tube is just a water tube - i have drilled some holes in---for cooling--
the reason why i have make that---is-- that the tram 2 make hum---worse when i hold my hand over it--the iron tube removed it totally--but remember the wire to input ground
i am not finished with the iron tube---have to paint it black--

Bjarne


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