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So yeah, as Chops said there's the full-size 6Z4 as well as the mini 6Z4 that's used in the XS.
...
I'm interested to hear your impressions on the three different volume pots. I was considering rigging up a switch setup to compare pots with but never got around to it.
Well, I know these 6Z4's are definitely the mini ones, as they're coming from a guy in Shanghai and they've got 7 small pins. And hopefully aren't cloudy like the one in my XS.
My impressions of the pot probably won't be much - I'll let James do that. I mostly worry about what it sounds like when it's being turned up or down. The one we've currently got in there is apparently quite expensive, but it makes a bit of a rushing noise (sort of a combination of a hiss and the sound of the ocean far away) when being turned up or down. Bit it sound quite good otherwise. I wouldn't expect too much of the pots I'm getting - nothing over $8US!!!
__________________
Jonty
It is impossible to build a fool proof system; because fools are so ingenious.
Chops, what kind of car did you borrow? I've done this before too with cars and bikes of friends. Such a great way to experience new machines for free.
Hey Derek,
Well at first, I was just borrowing it, for a day or two. But now, we have officially switched. We swopped my '02 Miata for his '02 Blazer.
Just in the past week alone, I have pulled the roof rack, properly reinstalled and realigned the headlights, realigned the hood, shaved all the emblems, washed it and detailed it inside and out as well as the engine compartment, and even managed to burn up the vacuum cleaner while vacuuming it out!
Near future plans include getting the windows tinted, dropping it 4" in the front and 3" in the rear, full tune-up, new rotor and cap, coil, plugs and wires, all Amsoil full synth oil, manual transmission fluid, rearend fluid, brake & steering fluid, custom chip, headers, hi-flo cat, 3" single exhaust (super quiet as well), upsizing the rear tires from 235/70-15 to 275/60-15 and eventually a posi-rearend and a supercharger.
And going from this...
To this...
__________________
HOTT Modded Xiang Sheng 708B Sennheiser HD600 Sony CDP-397 CD Player FEEDBACK My NEW Website!
Did anyone else's 708B come with a linear pot in the volume spot?
Mine did.
I have big plans for this little amp.
__________________
Originally Posted by mkmelt
ACHTUNG - ALLES KOPFPHONERLISTENERS
Alles kopfphonerlisteners non-technischens! Das tubenmachine is nicht for gefengerpoken und mittengrabben. Oderwise is easy schnappen der springenverk, blowenfus, und poppencap, mit spitzensparken, und smokentubes. Geverken inside der tubenmachine is fur der experten only. Is nicht fur geverken inside by das dumpkopfen. Das rubbernecken amateuren keepen das cotton-picken hands in das pockets. Just relaxen, enjoyen der musik, und vatchen das pretty glowentubes.
Did anyone else's 708B come with a linear pot in the volume spot?
Mine did.
I have big plans for this little amp.
how do you tell?
mine just says "B100K" on it...
__________________ Core2Quad Q6600 B3 @ 3.2GHz, 355x9 Asus P5W DH Dlx, Rev 1.03G, BIOS 2504
Sapphire HD3870, pencil modded
4GB G.Skill DDR2-800
Audigy 2 ZS with a Panny FM power filter, LM4562MA opamps, and electromagnetic shielding
Acer P221wBx
XP SP3
Currently listening to/watching/playing: The music in my head.
Cans: SR80 (modded), HD650 (BLISS!)
Plugs: JVC Air Cushion
Sources: Hotrodded Audigy 2 ZS, 16GB Modded Zen Micro, modded phat PSP
Gone: My marbles and a ton of cash
Amplification: Custom-built CMoy, Modded Xiang Sheng 708b
Want to hear: K701, K1000, GS1000, RS-2
Money spent on audio equipment since joining Head-Fi: $1000
Teamless
anyways, you measure from the input of the RCA to the input on the amp board.
As always observe HV safety.
With the volume set to min, it should read 100k.
If you set the knob to the middle of its travel it should be more than 70k for a 100k-ohm AUDIO pot. If it is 50k, its linear.
Linear pots also have a very non-linear volume scale. They only offer a few degrees of usefull range, with the rest offering little increase in volume for lots of spin...
This just means that when I have money again I have to get one of the Chinese steppers. maybe i can rig a shunt in the mean-time (yuck)
edited/added:
I added a 7.5k ohm shunt resistor between the output and ground. Its better than it was, but still leaves a little to be desired. Its just a band-aid until I can get some cash for a Chinese stepper.
__________________
Originally Posted by mkmelt
ACHTUNG - ALLES KOPFPHONERLISTENERS
Alles kopfphonerlisteners non-technischens! Das tubenmachine is nicht for gefengerpoken und mittengrabben. Oderwise is easy schnappen der springenverk, blowenfus, und poppencap, mit spitzensparken, und smokentubes. Geverken inside der tubenmachine is fur der experten only. Is nicht fur geverken inside by das dumpkopfen. Das rubbernecken amateuren keepen das cotton-picken hands in das pockets. Just relaxen, enjoyen der musik, und vatchen das pretty glowentubes.
anyways, you measure from the input of the RCA to the input on the amp board.
As always observe HV safety.
With the volume set to min, it should read 100k.
If you set the knob to the middle of its travel it should be more than 70k for a 100k-ohm AUDIO pot. If it is 50k, its linear.
Linear pots also have a very non-linear volume scale. They only offer a few degrees of usefull range, with the rest offering little increase in volume for lots of spin...
This just means that when I have money again I have to get one of the Chinese steppers. maybe i can rig a shunt in the mean-time (yuck)
edited/added:
I added a 7.5k ohm shunt resistor between the output and ground. Its better than it was, but still leaves a little to be desired. Its just a band-aid until I can get some cash for a Chinese stepper.
why not just get an alps black beauty?
__________________ Core2Quad Q6600 B3 @ 3.2GHz, 355x9 Asus P5W DH Dlx, Rev 1.03G, BIOS 2504
Sapphire HD3870, pencil modded
4GB G.Skill DDR2-800
Audigy 2 ZS with a Panny FM power filter, LM4562MA opamps, and electromagnetic shielding
Acer P221wBx
XP SP3
Currently listening to/watching/playing: The music in my head.
Cans: SR80 (modded), HD650 (BLISS!)
Plugs: JVC Air Cushion
Sources: Hotrodded Audigy 2 ZS, 16GB Modded Zen Micro, modded phat PSP
Gone: My marbles and a ton of cash
Amplification: Custom-built CMoy, Modded Xiang Sheng 708b
Want to hear: K701, K1000, GS1000, RS-2
Money spent on audio equipment since joining Head-Fi: $1000
Teamless
familygate only has linear rk40's. Michael Percy has audio RK40's but only mono, and by the time he responds to my first email, i could have had mikhail do it
I may just use a blue velvet. Im on the fence regarding whether I want better channel balance, or more precise control. I suppose the superior channel balance of a stepper could be negated by a flaw in one of my tubes, and an amp with this much gain does better with more control at the lower volume levels.
__________________
Originally Posted by mkmelt
ACHTUNG - ALLES KOPFPHONERLISTENERS
Alles kopfphonerlisteners non-technischens! Das tubenmachine is nicht for gefengerpoken und mittengrabben. Oderwise is easy schnappen der springenverk, blowenfus, und poppencap, mit spitzensparken, und smokentubes. Geverken inside der tubenmachine is fur der experten only. Is nicht fur geverken inside by das dumpkopfen. Das rubbernecken amateuren keepen das cotton-picken hands in das pockets. Just relaxen, enjoyen der musik, und vatchen das pretty glowentubes.
I just dug up my original stock pot from the parts bin and it's also labeled as B100K and measures at ~100kΩ. At the halfway point it measures ~50kΩ so it is indeed linear.
Hello All,
In Oz, we have 240v, 50Hz and this gives high volts (B+) of +215 on pcb, heaters of 7.3v ac, and the current thru the input valve (6N3, etc) is about 2.7mA, and 10.5 mA thru the 6N11s.
... jh
Hi folks,
It's a long time since I posted about my mods on here... Not had chance to do anything else with my amp since.
I just bought a 500VA autotransformer with 240V and 220V taps. Nominally the voltage in our house (UK) is 237V@50Hz, and usually between 231..243V when I check it, depending on the load in our house and time of year.
500VA is probably overkill, but I've got a couple of other 220V things I can run on it too. Check out Electronic components distributor. Electronic equipment and electrical products from Rapid part 88-1926.
The output of the autotransformer was bob on 220V with a 239V input this morning.
I'm going to take out the heater series resistors that I added for 240V operation, and have a quick play around with the HT power resistors to see how it runs on 220V. If it is ok, using the autotransformer is a load easier than messing around with some of the mods I did before! Also didn't like the idea of 240V feeding the transformer rated at 220V for long periods of time.
Will post an update if I ever get around to finishing the experiment!
I just dug up my original stock pot from the parts bin and it's also labeled as B100K and measures at ~100kΩ. At the halfway point it measures ~50kΩ so it is indeed linear.
well then, looks like my first mod(other than possible tube rolling or a 6x4 mod) will be to fit a new pot. the blue velvet looks like a winner 'til i can find someone that sells a black beauty or an elks pot for a decent price...
__________________ Core2Quad Q6600 B3 @ 3.2GHz, 355x9 Asus P5W DH Dlx, Rev 1.03G, BIOS 2504
Sapphire HD3870, pencil modded
4GB G.Skill DDR2-800
Audigy 2 ZS with a Panny FM power filter, LM4562MA opamps, and electromagnetic shielding
Acer P221wBx
XP SP3
Currently listening to/watching/playing: The music in my head.
Cans: SR80 (modded), HD650 (BLISS!)
Plugs: JVC Air Cushion
Sources: Hotrodded Audigy 2 ZS, 16GB Modded Zen Micro, modded phat PSP
Gone: My marbles and a ton of cash
Amplification: Custom-built CMoy, Modded Xiang Sheng 708b
Want to hear: K701, K1000, GS1000, RS-2
Money spent on audio equipment since joining Head-Fi: $1000
Teamless
Also didn't like the idea of 240V feeding the transformer rated at 220V for long periods of time.
Linear Mode
