Load Line, Q-Point, and Frequency Response in Excel

[Bob S]

Wow Martin - I just caught this. Thank You.
My brain hurts.

[surfsup]

Martin, this XLS is wonderful. I love the frequency response graph and will start playing with this to understand what you've built more.

Here is an XLS I took from Merlin a while back, I think, and added a page for the 6SL7. So the data is listed on the "graphdata" tab, if you're inclined to copy/paste it over into yours to add this tube to update your attachment. I don't remember the datasheet I used for the data but I'm relatively certain it was the GE 6SL7GT...and seems to work correctly.

I had to convert it to XLS since it was an XLSX so hopefully the sheet functions properly for anyone wanting to use a simplified LL plotter.

[leadfootdriver]

Great!

[martin manning]

Martin, this XLS is wonderful. I love the frequency response graph and will start playing with this to understand what you've built more.

Here is an XLS I took from Merlin a while back, I think, and added a page for the 6SL7. So the data is listed on the "graphdata" tab, if you're inclined to copy/paste it over into yours to add this tube to update your attachment. I don't remember the datasheet I used for the data but I'm relatively certain it was the GE 6SL7GT...and seems to work correctly.

I had to convert it to XLS since it was an XLSX so hopefully the sheet functions properly for anyone wanting to use a simplified LL plotter.

Thanks! Unfortunately the table formats are transposed and inside-out to each other, so it would be easier to start from scratch on the 6SL7. If anybody is so motivated, feel free to create and post additional tables here, like Hellhammer did above for the ECC88.

[surfsup]

ok working on the 6sl7...

[overtone]

surfsup, I really appreciate the 6SL7 input, thank you,
best, tony

[surfsup]

Okay I added the 6SL7 input and also put in the ECC83 data from Hellhammer I think it was.

Martin, the graph functions properly, but the gain calcs are not working, etc. Since you set this spreadsheet up, perhaps you can debug it more quickly? Hate to ask you to do that... (btw, I probably will never build a 6SL7 amp LOL)...

I'll have to see how to add another custom button since I just used up the two spares. I'd like to add a 6SN7 to the mix as well.

[martin manning]

In the interest of configuration control, please do not post new versions of the workbook so that there is only one "official" version that I can maintain and update. Just posting the tables for additional devices is best, as anyone can paste whatever device they are interested in into the available custom slots as needed. I don't know why any of the calculations would fail to work if the table fits the format.

[surfsup]

6sl7 updated. I removed the 0.01 and 0.03 Ia rows and tightened it up.

[martin manning]

The 6SL7 still looks a bit rough Surf. Note that the plate curves themselves and the ra and mu plots are not very smooth at all in some places, and the blanks in the lowest current rows are giving crazy calculated ra values on the -4 and -5V grid lines. It does take some effort to make a good data table that will produce accurate results.

Also, I believe you are using the 12-56 (December 1956) GE data sheet, not 1960, and I would have just used the set of curves on the bottom of page 3 with 0.5V Vg-k increments (13 grid lines), and left it at that.

[pch64]

Hello,
This is my first post in this forum (I haven't started yet my Wreck build).
My experience is with 18WLite that I have build from scratch and later converted to 6V6 TMB. I have also repaired and restored some vintage amps.

I am using Excel for calculating load lines but for the push-pull stage. I have digitised some of the curves for the most popular power tubes from the Philips and Mullard datasheets. The problem is that in those datasheets we can find curves for only a limited number of Vg2 voltages.

My sheet is simple and I don't know how to automatically get the values from the graph intersections so Eac and Eab have to be entered manually. I am using the method from this site:
http://www.turneraudio.com.au/loadmatch ... trodes.htm
which is similiar to those of Valvewizard.

Here is an example from EL84 Mullard datasheet for a 15W push-pull amp (values are for continuous sine wave). My calculation is giving 15.9W max power but it's not taking into account the power supply voltage drop.

Regards,
Peter

[surfsup]

updated 6sn7

[martin manning]

updated 6sn7

Looks much better. Where did you get the Cg-a and Cg-k? Those are not listed on the GE 6SL7 data sheet. 1954 RCA data lists these as 2.8pF and 3.2pF (avg of s1 and s2) for this tube type, and those larger values will move the HF rolloff down.

Everything that you put in a model that is to be used by others should be referenced, and if something has been estimated by you that fact should be documented as well so that users will be aware of it.

[surfsup]

I got one from here, then just filled in the other to make sure the graphs were working, after editng the data I forgot about the fact I fudged those. I used the non-GT value as well since the GE sheet didn't specify. Good catch.

[Reeltarded]

It has to be that next stage.. huh buddy?

lol

BUMP for awesome