do you have it muted
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That sucks, so I suppose the unit has to go back?
Off that subject I still have not switched between those two tube configurations but reading your replies and Knghifi it appears that your pres were set opposite when received. Are they normally sent out set in a specific? and if so what is that?
Question to any owners, curious what have you found the sonic differences to be when you switch from between 8416 or 6922/e88cc/7308.
The Sig MKII uses 8416. The earlier Sig MKIIa uses 6922/e88cc/7308. The later Sig MKIIa has a switch (6.3 volts and 12.6 volts) where you can use 6922/e88cc/7308 or 8416.
My Sig MKIIa has the switch and stock tube is Golden Dragon e88cc. The preamp works fine and sounds FABULOUS. I don't have any 8416 to test and don't plan to roll any 8416. Kevin recommends Philip 6922/e88cc/7308 as an alternative to stock so between those 2, there's no reason to roll any 8416 even though it's also an excellent tube.
Pookie10, I suggest you contact VAC and return the unit for repair. The preamp probably got damaged during transit. I know Kevin personally test/listen to every Sig before shipping so if the 8416 was in the preamp at VAC, it was working before ship.
The Amperex NOS 7308 gold pins has a bolder and more neutral with better defined edges compare to Golden Dragon e88cc ... Golden Dragon is softer. One is not better than the other but just different. I'll probably roll some Ediswan and Mullard down the road but for now I'm very satisfy with sound.
I also ask Kevin about HiFi Tuning Gold fuses. Here's his reply
The labeling on the hifi 'tuning' fuses suggest that they may incorporate a capacitor bypass across the fuse element, which will to a small degree assist in filtering any harmonic content due to thermal tracking. Logically, this would be more of an issue with a Class AB or Class B power amplifier than with a Class A preamplifier, but I've learned not to use theory to prejudge the result.
Since I purchased the fuse after placing order for the preamp, I AB against stock while keeping everything else constant. I found HiFi Tuning sound was noticeably smoother and less hifi-ish. I heard someone @theCableCo found the fuse made no differences in his Sig MKII. I don't know his system and NOT surprise it's system dependent. With many many thousand invested in a system, $35 is worth a try.
HiFi Tuning fuse is directional. In the wrong direction, the sound is lean and constricted. I use HiFi Tuning fuses in all my components and have never found direction alters the sound so dramactically as in the VAC.
Hi Knghifi, great info.
I also use HiFi fuses in other gear with great sucess, I haven't opened up my units and there being the two units with lots of screws to be removed how many fuses are needed and which component are they in.
What is the size needed and the direction you find works best.
How many hours do you have on your pre now.
Have you tried many different power cords, as you know I'm using a Stealth Dream. I currently have my pre placed on 3 small Sistrum points placed onto a Symposium Ultra platform, power supply on murtal blocks. I noticed having them stacked when playing my table there was some noise, nothing when playing read book, since they have been separated the noise has been eliminated.
My Vac Preamp did the same thing with My 12AU7's. I took them out and swapped postions and pulled and reinserted a few times and the tubes work fine. You may have had a pin not making proper contact. I am curious has anyone compared the 8416 variant to the 6922/7308 variant? Is there any sound difference?
It takes one 5 x 20 mm, 4 ampere, slow blow type. Fuse holder is below the IEC on the Power Supply unit. Facing the fuse holder, the direction worked best for me is right to left.
I have 550+ hours on my preamp and broken in. I ran it 24/7 for the first 300 hours ... didn't want to begin tinkering until it's fully broken in.
I'm using ASI Liveline power cord. I replaced all SR Tesla Apex, Hologram ... in my system to ASI Livelines. My next focus is my room, component stands, isolation platforms ...
I asked Kevin at VAC about which direction the fuse should go in. Here is his reply:
"the current through the fuse is alternating current, is it goes in one direction for 8.33 milliseconds, and then the other direction for 8.33 milliseconds, and so on.
In terms of which end of the fuse connects to the 'hot' leg of the wall current, it is to the right side of the chassis when viewed from the front."
So that would mean looking at the back of the unit putting the fuse into the holder, the arrow should point left-to right. But I suppose one should trust their ears versus this.
Just did A-B comparison on fuses with digital and analogue. For vac 300.1a in rank order best sounding to less best:
1. Stock fuse (most ambience and roundess - front to back depth)
2. Hi-fi tuning left to right facing fuse holder (reduced some glare but flattenned front to back)
3. Hi-fi opposite direction (flattened and deadened sound)
In all other applications hi-fi wins (all other components incl speakers) but with vac amp i am not feeling the love.
Hi, Dev. I have the Hi-Fi Supremes all the way around -- they have probably 100 hours on them. The 300.1a came with ceramic fuses while the power supply to the Renaissance Mk III preamp came with glass. I just took out the Hi-Fi Supreme from the preamp power supply. The stock fuse slightly lost some of the harmonic weight and richness and delicacy the Hi-Fi Supreme provided. So go figure -- works like a champ in preamp but not so much in 300.1a.
Podeschi, the more open sound direction is probably out of phase. Initially I prefer the correct direction but flipped it ... guess fuse was not fully broken before my experiment.
I replaced all my HiFi Gold and Supreme with Audio Magic Nano-Liquid fuses and very happy with the results. It's like replacing a high quality SS amp with a high quality Tube amp. More liquid eliminating any grain and digital glare, less congestion, bloom and beautiful tone. I didn't believe until I tried. According to Jerry at Audio Magic, it only take 24 hrs for break-in.
Snook2, I had my hearing tested and it's excellent but it helps with high quality components. Everything makes a difference and I don't debate with the skeptics ... just a waste of time :-):-)
Reversing fuse-- reversing phase?
I don't see why reversing the direction of the fuse would reverse the absolute phase of the signal. Not to say that absolute phase doesn't matter. Since there's no standard in the industry, let alone that a standard would be followed anyway, having a phase reversal switch on your remote makes it a simple matter. Usually I can tell if a recording starts playing with proper absolute phase without having to switch it first for a comparison.
Nonetheless, I'm not suggesting that reversing the direction of a fuse doesn't matter. I've long ago stopped assuming that I know whether something matters without having personal experience trying it. It never ceases to amaze me when a change that I assume shouldn't matter-- does.