Rocket and Rectifiers

[rawnster]

Ok, I checked some voltages and saw about a 6 volt difference between the JJ and NOS Mullard. The JJ was around 298v on pin 8, the Mullard was around 304v. The other measurements were with one or two notches different than what I originally posted when posting the amp.

JJ GZ34
Primary Voltage = 124 ac
B+3 = 224
B+4 = 197
B+5 = 192

V8 Recto
P1 = ---
P2 = 298
P3 = ---
P4 = 254 ac
P5 = ---
P6 = 254 ac
P7 = ---
P8 = 298

NOS Mullard GZ34
Primary Voltage = 121.5 ac
B+3 = 225
B+4 = 198.5
B+5 = 194.3

V8 Recto
P1 = ---
P2 = 304
P3 = ---
P4 = 253.5 ac
P5 = ---
P6 = 253.5 ac
P7 = ---
P8 = 304

[RJ Guitars]

Rawnster,

I think the voltage on the plate of V1 is of great significance... do you have that for the two different tubes?

If you have the tools to do it, I think it would be really interesting to watch that voltage as you really work the amp hard.

thanks

rj

[Zippy]

Ok, I checked some voltages and saw about a 6 volt difference between the JJ and NOS Mullard. The JJ was around 298v on pin 8, the Mullard was around 304v.

Hmmm, how 'bout that?

Yes, as RJ asked, please see where your V1, V2, PI, etc. voltages fall. I'll bet the differences are greater as they propagate through the amp.

Looks like I succeeded in getting past "subtle" but failed in "explicit."

My interest, lest I be too subtle once again, is to get your "sweet spot" voltages and dial them in via dropping string adjustments and a solid state rectifier.

Thanks, Rawnster. Good stuff!

[rawnster]

You know, I was going to get all the valve readings but thought ya'll only needed the b+ and recto readings. My bad. Once again, I'll get it tonight once I get home from work.

Hey Zippy, yeah please be explicit. I can't read between the lines with my wife, much less with amp building friends.

Good thing I'm having a hard time putting the head cab together for the chassis. Off topic: I ordered one of the cherry drawers from Ron Worley's BOM of the express. Got the wood in a couple of days ago and found that it was seriously cracked in several places. They made go for it though; I should be receiving a new box by the end of the week....I hope!

[Zippy]

You know, I was going to get all the valve readings but thought ya'll only needed the b+ and recto readings. My bad. Once again, I'll get it tonight once I get home from work.

Thanks.

RJ and I have a friendly "wager" about what your V1 plate voltages will be.

+1 on reading the wife. The only guys that consider themselves "successful" at predicting what their wives are thinking are probably divorced.

[jumpbluesdude]

First, you have to realize that a tube is a mechanical device, not an electrical device. Second, EVERYTHING affects tone...the question is can you hear it? So what is different in these tubes? In a word, construction. The metals used, the thickness of mica when its used, the distances between elements, the gas used in the vacuum, and most important, the chemicals used to coat the elements. Tubes have a lot of parts and can sound very different from each other even though they may meet the same specs. The new Mullards are not reproductions of the origionals, they are more like a reissue. Thats my 2 cents.

[dartanion]

First, you have to realize that a tube is a mechanical device, not an electrical device.

Are you sure about that? They are not referred to as electron tubes because they're mechanical devices. Grab a receiving manual and start reading. Enlightening stuff in those babies.

I will agree about manufacturing variance and materials used, however, the rectifier is not directly in the signal path, therefore it's tonal qualities are more so in how it affects the operation of the circuit.

[Zippy]

First, you have to realize that a tube is a mechanical device, not an electrical device. Thats why it is unaffected by EMP. Second, EVERYTHING affects tone...the question is can you hear it? So what is different in these tubes? In a word, construction. The metals used, the thickness of mica when its used, the distances between elements, the gas used in the vacuum, and most important, the chemicals used to coat the elements. Tubes have a lot of parts and can sound very different from each other even though they may meet the same specs. The new Mullards are not reproductions of the origionals, they are more like a reissue. Thats my 2 cents.

Congrats! You just pegged my analog bullshit meter.

[rawnster]

First, you have to realize that a tube is a mechanical device, not an electrical device. Thats why it is unaffected by EMP. Second, EVERYTHING affects tone...the question is can you hear it? So what is different in these tubes? In a word, construction. The metals used, the thickness of mica when its used, the distances between elements, the gas used in the vacuum, and most important, the chemicals used to coat the elements. Tubes have a lot of parts and can sound very different from each other even though they may meet the same specs. The new Mullards are not reproductions of the origionals, they are more like a reissue. Thats my 2 cents.

Congrats! You just pegged my analog bullshit meter.

Zippy your subtly is off the charts!

[rawnster]

Ok, the rest of the voltages. Not much change except for a bit in the power tubes. Anyway.....

JJ recto
V1
P1 = 123
P2 = ---
P3 = .94
P4 = 3.15 ac
P5 = 3.15 ac
P6 = 82
P7 = ---
P8 = .74
P9 = 3.15 ac

V2
P1 = 197
P2 = 123.2
P3 = 123.3
P4 = 3.15 ac
P5 = 3.15 ac
P6 = ---
P7 = ---
P8 = ---
P9 = 3.15 ac

V3
P1 = 178
P2 = 27.9
P3 = 42.7
P4 = 3.15 ac
P5 = 3.15 ac
P6 = 179
P7 = 28.1
P8 = 42.7
P9 = 3.15 ac

V4 - V5
P1 = ---
P2 = ---
P3 = 9.2
P4 = 3.15 ac
P5 = 3.15 ac
P6 = ---
P7 = 293
P8 = ---
P9 = 292

V7 - V8
P1 = ---
P2 = ---
P3 = 9
P4 = 3.15 ac
P5 = 3.15 ac
P6 = ---
P7 = 291
P8 = ---
P9 = 290

NOS Mullard GZ34
V1
P1 = 123
P2 = ---
P3 = .97
P4 = 3.15 ac
P5 = 3.15 ac
P6 = 72.4
P7 = ---
P8 = .68
P9 = 3.15 ac

V2
P1 = 198.4
P2 = 122.8
P3 = 122.8
P4 = 3.15 ac
P5 = 3.15 ac
P6 = ---
P7 = ---
P8 = ---
P9 = 3.15 ac

V3
P1 = 179.7
P2 = 31.8
P3 = 47
P4 = 3.15 ac
P5 = 3.15 ac
P6 = 170.5
P7 = 30.1
P8 = 42.7
P9 = 3.15 ac

V4 - V5
P1 = ---
P2 = ---
P3 = 9.2
P4 = 3.15 ac
P5 = 3.15 ac
P6 = ---
P7 = 296.2
P8 = ---
P9 = 294.6

V7 - V8
P1 = ---
P2 = ---
P3 = 9
P4 = 3.15 ac
P5 = 3.15 ac
P6 = ---
P7 = 298
P8 = ---
P9 = 294

[Zippy]

Ok, the rest of the voltages. Not much change except for a bit in the power tubes. Anyway.....

JJ recto
V1
P1 = 123
P6 = 82

V2
P1 = 197

V3
P1 = 178
P6 = 179

NOS Mullard GZ34
V1
P1 = 123
P6 = 72.4

V2
P1 = 198.4

V3
P1 = 179.7
P6 = 170.5

Thanks, Rawnster. What tubes are you running?

[rawnster]

Zippy, I'm running the following:

V1: old tung-sol 12AX7
V2: Groovetubes -7025 12AX7
v3: tung-sol reissue 12AX7

pt: saratovs el84s

[jumpbluesdude]

Zippy, when they said women like a big dick, they didnt mean you had to be one.

[jumpbluesdude]

tonal qualities are more so in how it affects the operation of the circuit.

If the rectifier didnt make a tonal difference, then why is it that KF wouldnt build a Rocket unless he could get a Mullard GZ-34? Do you really believe it was 6 volts, like zippy? Ill give you a clue: the power supply is audio ground. Think about it. You wont find the answer in a tube manual.

[Zippy]

Think about it. You wont find the answer in a tube manual.

Nor reality.

Why so hung up on what Ken did or didn't do? He didn't build all that many Rockets so how do you know what he would have done, given time to evolve the design?

I hope that, too, didn't upset you (much).

Be well.