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DIY HiFi Supply Parts and Kits from Diy HiFi Supply

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Old 29th April 2013, 03:51 PM   #711
Desmo is offline Desmo  Denmark
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Originally Posted by Falck View Post
. Are there any other heatsinksolution for the Colmanregulator that is good?

Best Regards
Mats Falck
Hi Mats,

Some have simply super-glued the transistors on the Rod Coleman regulators directly to the inner sides of the chassis. This is certainly a very easy way of implementing the regulators..! (and quite ''rough'' some might say)...
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Old 29th April 2013, 05:05 PM   #712
sjs is offline sjs  United Kingdom
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Originally Posted by Desmo View Post
Hi Mats,

Some have simply super-glued the transistors on the Rod Coleman regulators directly to the inner sides of the chassis. This is certainly a very easy way of implementing the regulators..! (and quite ''rough'' some might say)...
Inspired by Rod Coleman's posts earlier in the thread and his suggestion of a heat spreader, I have made some from 5mm aluminium which fit inside the Tram2 chassis. They have 2 holes to bolt to the chassis, and 4 threaded holes to mount the TO220 packages and 2 x 5mm stand offs to hold the PC

Click the image to open in full size.

I will try to take some pictures when I have time to fit them.

Last edited by sjs; 29th April 2013 at 05:15 PM.
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Old 29th April 2013, 05:13 PM   #713
sjs is offline sjs  United Kingdom
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Originally Posted by Desmo View Post
It's fine sjs, if you're happy with it all is good I know what you're saying, and I understand all you say (I have worked with electronics for 30 years), I just don't have the words in English to discuss this... So I rest my case on the technical stuff...

Our experience here is just, that the load these type of triodes ''see'' on their output has big impact on the sound and that they need this load on a few K ohm to sound their best. Your experience is different, and that's fine, and with you approach the output caps are cheaper
Desmo, if you have a pair of 1M0 resistors you can risk trying it out and see if it makes any difference
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Old 29th April 2013, 06:22 PM   #714
Desmo is offline Desmo  Denmark
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Of course I will try it...
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Old 2nd May 2013, 04:05 AM   #715
Mihan is offline Mihan  New Zealand
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Originally Posted by Nonnegativ View Post
Great - Thanks. I will look forward to that.

The response from Diyhifisupply in December 2012 regarding the FCPSU-board was:

""We run out of FCPSU, at first I expect some new ones will come soon then there are some changes at last. We used to use them in power amps well but it became unstable. But if we use them just for preamp it's difficult to meet the MOQ."

I had to google MOQ: "Minimum Order Quantity"

The Order was later cancelled on behalf of diyhifisupply due to inability to supply new Boards.

So treat your FCPSU-boards with care - I am not sure it will ever be made again.
What were the changes between version 1.0 and version 2.1 of the FCUPS modules and have other tram owners had stability issues with either version?
I know one DIY'er who has used 4 modules in two power amps and has had no problems.
As Desmo says the boards contain readily available parts and can be repaired if necessary.
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Old 4th May 2013, 12:01 AM   #716
rab28 is offline rab28  Australia
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Originally Posted by Desmo View Post
I now use the Chatham-Electronics 6AS7, I like it better than my other 6AS7 tubes
Based on your experience, I just bought one of those on eBay.

I have now also received my Philips rectifier tube. Thanks again for your helpful reports Morten! (Still waiting to receive my replacement CCS board from Simon though... so everything is still on hold...)

Quote:
Originally Posted by Desmo View Post
I would not be surprised if the output cap sounds better with the 2.2uf removed, even considering that the 2.2uf tin-foils sounds better than the 10uf gold.
My friend with the Tram2 is actually using a very high quality output cap (sorry, i am not sure what it is), but a very low value, only about 4uF. His Tram2 sounds very very good, but i understand that the (too) low cap value may be removing too much bass. I have been told that as long as the capacitance is at least 5-6uF, it should work well. If that is correct, then it may allow us to afford higher quality caps with lower values in our Tram2s. Has anyone else tried lower capacitance on the output caps? Morten, i wonder how your Tram2 would sound if you used only 3 (or 4) of your tin foil Obbligatos per channel?

- richard
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Old 4th May 2013, 04:34 PM   #717
Desmo is offline Desmo  Denmark
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Originally Posted by rab28 View Post

My friend with the Tram2 is actually using a very high quality output cap (sorry, i am not sure what it is), but a very low value, only about 4uF. His Tram2 sounds very very good, but i understand that the (too) low cap value may be removing too much bass. I have been told that as long as the capacitance is at least 5-6uF, it should work well. If that is correct, then it may allow us to afford higher quality caps with lower values in our Tram2s. Has anyone else tried lower capacitance on the output caps? Morten, i wonder how your Tram2 would sound if you used only 3 (or 4) of your tin foil Obbligatos per channel?

- richard
This depends on what compromises you want/can live with...

You can easily calculate the corner frequency with different cap values since all the variables are known. The formula is: f = 1 / 2 * pi * R * C where R is the resistance in ohm and C is the capacitance in uF. R = the resistor network on the output // the input impedance of your power amp. If the input impedance is (for instance 47K) then R = 3500 ohm. With 6 x 2.2 uF as output cap the cap total is 13.2uF. Put the numbers into the formula and we have a corner frequency of approx 3,5hz.

One should think this is waaaay low enough since the audible range does not start before 20hz, however there is a ''phase turning'' (no idea if this is the proper English word, I guess not) up to about 10 * the corner frequency, meaning to 35hz in the example. So even with 13.2uF the phase is not flat in the first octave of the audioband. If we change the cap to just 4uF then the corner frequency goes up to approx 11.5hz, meaning that the phase is not flat until around 115hz. Having the phase ''turning'' well into the audio range is not a good thing and personally I would never do this...

So normally output caps are calculated for a corner frequency on around 1hz or so, meaning the phase is smooth from around 10hz or so to have a perfectly flat phase throughout the audio band. But if people think phase is not important smaller caps can be used...
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Old 4th May 2013, 09:32 PM   #718
kazap is offline kazap  Australia
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Quote:
Originally Posted by Desmo View Post
......
So normally output caps are calculated for a corner frequency on around 1hz or so, meaning the phase is smooth from around 10hz or so to have a perfectly flat phase throughout the audio band. But if people think phase is not important smaller caps can be used...
Thanks. This is fascinating. Im struck at how the input impedance of the power amp is critical in the phase shift frequency. If Richard's friend has tubed power amps with input impedance over 100kohm he can half his capacitance value which might explain how he gets away with such a small output cap.

I wonder if subtle phase shift is audible in the lower bass frequencies?

I think the phase shift can cause volume attenuation with large shifts and loss of imaging definition in smaller shifts.

Some say imaging doesnt happen in the lower frequencies anyway?
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Old 4th May 2013, 09:48 PM   #719
Desmo is offline Desmo  Denmark
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Originally Posted by kazap View Post
Thanks. This is fascinating. Im struck at how the input impedance of the power amp is critical in the phase shift frequency. If Richard's friend has tubed power amps with input impedance over 100kohm he can half his capacitance value which might explain how he gets away with such a small output cap.

I wonder if subtle phase shift is audible in the lower bass frequencies?

I think the phase shift can cause volume attenuation with large shifts and loss of imaging definition in smaller shifts.

Some say imaging doesnt happen in the lower frequencies anyway?
No, it's the other way around... Input impedance of the power amp has about zero influence on the corner frequency for the Tram II because the input impedance is in parallel with the restor network on the Tram II output. And the network has a value on just 3.8K ohm.

Look at the formula and my post again... I have just described what the corner frequency is using a 4uF output cap. The corner frequency is determined by the resistor network on the output of the Tram, not by the input impedance of the amp (unless the input impedance is very low). So his corner frequency and phase shift is as I have just desribed...
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Last edited by Desmo; 4th May 2013 at 09:56 PM.
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Old 4th May 2013, 09:59 PM   #720
kazap is offline kazap  Australia
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Originally Posted by Desmo View Post
No, it's the other way around...
Thanks for setting me straight . I understand now.
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