Resistance/Voltage checks
- Thread starter troplin
- Start date
Natural Sound
New member
troplin said:
According to the GE datasheet this voltage should be 6.3v +- 0.6v or 5.7v to 6.9v. Your measurement of 6.45v is within that range.
http://www.mif.pg.gda.pl/homepages/frank/sheets/093/6/6FJ7.pdf
Natural Sound said:
Hey Natural Sound, thanks for that link.
It seems that the tube has quite some tolerance.
I couldn't wait any longer and put it into service, together with the new Blumenstein Orcas. It's working fine. I might still make some corrections but for now it seems ok.
The new combo replaces a Cambridge SoundWorks 2.1 system for my computer.
But to be quite honest, I don't yet know which one I like better sound wise. They certainly sound different. But the old system also seems to be quite good (but it's not mine).
If nothing else, the SEX/Orca combo looks way better. ;D
Natural Sound
New member
troplin said:
If the Orca's are new they will take some time to reach their full potential. The same goes for your new S.E.X. 3.0. Also, here is a tip I got from Clark Blumenstein a few years ago that might help.
For what its worth I have an old Cambridge SoundWorks 2.1 system for my computer as well. Mine is from back in the days when Henry Kloss was still alive and designing for them. It does sound very good indeed. But in my humble opinion there are no match for a S.E.X./Orca setup. Especially when you add a Blumenstein sub.
Enjoy!
tsingle999
New member
The Orcas sound their best after a few hundred hours. Play them loud.
I recently put some old desktop speakers (Scirocco s30) back in to compare to Orca's and the Orcas are so much more lifelike it was no comparison. Its always fun to compare to old things that you thought sounded really good. But YMMV as everyone has their own preferences.
I recently put some old desktop speakers (Scirocco s30) back in to compare to Orca's and the Orcas are so much more lifelike it was no comparison. Its always fun to compare to old things that you thought sounded really good. But YMMV as everyone has their own preferences.
Natural Sound said:
tsingle999 said:
Yeah, the ominous "break in".
I don't really enjoy music too loud at the moment though as I've often got headaches since 1-2 years.
And my room leaves much to be desired. Reverb time (RT60) is about 1s, which I find very fatiguing. Everything seems loud. And there seem to be some nasty standing waves.
Natural Sound said:
tsingle999 said:
That's true, often switching to something better is not a big deal, but switching back to something inferior makes a huge difference.
I'm really not an audiophile, I just enjoy music. All that jargon (soundstage, resolution, tight bass, etc) doesn't tell me much, I can just tell if I like something or not. And sometimes even that is difficult.
Yes, 6.45V is less than 3% off of the nominal, so you're OK.
Caucasian Blackplate said:
Ok, thanks PB.
Now that difference between the added voltages H2 + H4 (3.40+3.26 = 3.66V), and the effective heater voltage (3.45V), where does it come from?
Is this likely an error of my meter measuring the unfiltered "DC" voltages coming from the rectifier?
Doc B. said:
Sure, I'm enjoying the music as I'm writing, just as I did most of the time in the past few days.
But that doesn't hinder me from asking annoying questions.
I'm just trying to understand a bit what I'm doing.
It's almost embarassing to admit that I've actually a degree in electrical engineering (more IT though), so I should actually understand at least the basics. But I never actually worked in that area, so I've already forgot most of it, which is a bit sad.
You can think of this as analogous to the "12V" lights and electronics in your car. When your car is running, and you have 14.4V coming out of the alternator for the 12V electrical system, this doesn't burn out all the 12V components because there is an allowable tolerance in voltages that they are designed for.
If you look at the datasheet for the 6FJ7, the allowable voltage for the heater supply is specified within, and you are in the acceptable range, so there isn't a lot more to say.
If you look at the datasheet for the 6FJ7, the allowable voltage for the heater supply is specified within, and you are in the acceptable range, so there isn't a lot more to say.
Ah, I should have been a bit clearer.
I totally understand what tolerances are and I'm fine with the measurements being off when they are still in the tolerance.
OTOH, it feels much better to actually know why the measurements are off. I always want to understand everything. I'm not asking for advice, just information.
As far as I understand the circuit, there's only a low pass filter between the rectifier and the heater, so the voltages should be approximately the same, except that they are filtered on one side and unfiltered on the other.
So (assuming I didn't screw up the measurements) my only explanation would be that my meter isn't very reliable if the voltage is not filtered. Which would again imply that I have to take all DC-measurements of my meter that are not known to be constant voltage with a grain of salt.
But I also understand that this isn't support for your products anymore, so don't feel obliged to answer.
I totally understand what tolerances are and I'm fine with the measurements being off when they are still in the tolerance.
OTOH, it feels much better to actually know why the measurements are off. I always want to understand everything. I'm not asking for advice, just information.
As far as I understand the circuit, there's only a low pass filter between the rectifier and the heater, so the voltages should be approximately the same, except that they are filtered on one side and unfiltered on the other.
So (assuming I didn't screw up the measurements) my only explanation would be that my meter isn't very reliable if the voltage is not filtered. Which would again imply that I have to take all DC-measurements of my meter that are not known to be constant voltage with a grain of salt.
But I also understand that this isn't support for your products anymore, so don't feel obliged to answer.
Nah, we are totally OK going into the technical side.troplin said:But I also understand that this isn't support for your products anymore, so don't feel obliged to answer.
The heater current draw of a tube like the 6FJ7 won't be completely consistent from tube to tube, and your line voltage is going to not be 100% in the middle of the range of powerline voltages for the power transformer primary winding selection you used, so there will be some variation in this DC voltage from these combined forces.
-PB
Caucasian Blackplate said:
Ah yes, the heater current...
My assumption that the low pass filter doesn't change the overall voltages was wrong. That 0.1Ω resistor in the low pass filter will of course lower the voltage if you draw any current. The heater current is 0.9A per tube, which leads to a voltage drop of 2*0.9A * 0.1Ω = 0.18V, close enough to the 0.21V difference that I measured.
Mystery solved, thanks!
Adrian
New member
http://bottlehead.com/smf/index.php?topic=9851.msg91550#msg91550
All of your measurements in the heater supply diode bridge circuit were well with allowable range.
As was said in a previous post "...there isn't a lot more to say."
All of your measurements in the heater supply diode bridge circuit were well with allowable range.
As was said in a previous post "...there isn't a lot more to say."
Adrian said:
My understanding was that if the voltage is specified as a range in the manual, it should be within that range and the +/-10% only applies to non-ranged values. I could be wrong though.
Anyway, as I said in my second last post, I just wanted to understand what I'm actually measuring because the values were not aligned with what I thought they should be. But that's now solved.
Adrian said:
There's always more to say ;D
For example my next question could be "Why is the allowable Range at the H-Terminals 2.8-3.2V, which will result in an effective heater voltage range of 5.4V-6.2V (the missing ~0.2V being lost on the 0R1 resistor), which is lower than the heater voltage range specified in the 6FJ7 manual (5.7V-6.9V)? Even the nominal voltage of 6.3V is outside of that range."
But I think I'll refrain from actually asking that question. :-X
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