Ideal V1 & V2 Cathode Voltages?

[odourboy]

My own limited experience support what you all say about it being critical to get the plate and cathode voltages right and large operating point variations between different tube brands and even tube lots can really mess with your mind .

Could I get an authoritative opinion as to the suitable target voltage or range for cathode voltage of each preamp stage. Second, is this operating point pretty much dead center or is it skewed toward saturation or cuttoff?

Thanks! Brian

[Darkbluemurder]

V1: 195-205V
V2: 210-220V

[odourboy]

V1: 195-205V
V2: 210-220V

Thanks Dark! Now that we've established the plate voltages, any opinions on the cathode voltages?

[Darkbluemurder]

Sorry I misread your post. I have never measured the cathode voltages except for cathode followers but they are not used in the ODS preamps (only D-lator).

[dobbhill]

See attached voltage chart. Hope this helps.
D

[odourboy]

Excellent! Thank you sir.

[dogears]

Keep in mind that the chart posted is EL34 outputs with the 90s power supply. The dropping string is 2.2>15K>10K. It is HRM. Your voltages using the 80s string are going to be closer to what V1 had. I would not recommend 230V on V2

Excellent! Thank you sir.

[ampgeek]

Here is a voltage chart for the DLite with 6V6.
Hope that it helps!
Dave O.

[dogears]

Hey Dave,

The cathode voltages look low on the "b" triodes of V1 and V2. Is it 150k/2.2k there??

Here is a voltage chart for the DLite with 6V6.
Hope that it helps!
Dave O.

[kleinm]

Hey Dave,

The cathode voltages look low on the "b" triodes of V1 and V2. Is it 150k/2.2k there??]

For the stock BN D'Lite:
V1b = 150k/2.2k
V2b = 120k/1.8k

[odourboy]

Hey Dave,

The cathode voltages look low on the "b" triodes of V1 and V2. Is it 150k/2.2k there??

Here is a voltage chart for the DLite with 6V6.
Hope that it helps!
Dave O.

This is exactly the sort of insite I was hoping to gain with my initial post. Given how much variability there seems to be between preamp tubes both within and between manufacturers, I wanted to see what sort of ranges you all were getting on these measurements. FWIW, I had a set of Sovtek 12AX7WAs in my most recent project (used only for initial testing purposes ) and the plate and cathode voltages on both 'B' sections were so low, I thought I had a bug. Switched tubes and voila! Fixed.

Anyway, great stuff! Having the supply voltage really helps as well (as per the two charts you guys posted). Thanks! Keep 'em coming if you feel so inclined. It would be nice to have a good sample set from good sounding amps.

[ampgeek]

Here is a link to the stock DLite schematic from the good folk(s) at BrownNote.

http://www.brownnote.net/forum/viewtopic.php?t=274

Yep...I always thought that the triode B side cathodes "felt" a tad low (~1.25ma at the "magical" 200V on plates). But.....it is an excellent sounding amp with both 6V6 and 6L6 type tubes.

I did a homegrown DLite version and stuffed it into a Bogen metal enclosure. Still working the face plate graphics and speaker enclosure (will be using one of Funk's G1265s) but, even at this point, I really like the sound of this circuit!

http://www.brownnote.net/forum/viewtopic.php?t=382

Not sure how close it comes to the real deal but, as we know, there is so much tonal variation due to guitar/PU type, speaker type, playing style, mic placement, room characteristics, etc...I don't think that a totally objective comparision is possible.

Sure, there are certain bench mark traits that define a given circuit but even those are open to some debate. However, to my ears, the vast majority of the clips both here at over at BN all have that certain "something" that put the circuits used to make them into the "D" territory (at least as we know it from our guitar heros using them).

I guess that when the day is done, we only ask ourselves: Is that the tone that I was after?. If not...ask a few questions, do a little research and tweak it a little more! If yes...what shall I build next?!?

Which leads me to my (long winded) point: It sure is nice to have resources such as this and the other forums that we all haunt with experienced folks willing to so openly share their knowledge!

Much thanks to all,
Dave O.