Ok. I really looked before I came back here but I am confused by this quote and which caps we are speaking of now: "The stock electrolytic power supply caps have been disconnected, and replaced with a Mundorf Mylitic capacitor. This cap is huge, and needed to be relocated under the transformer cover, but makes a significant addition to the sound."
Are these the two 100uf 400V caps and they're removed and replaced with a single cap? Does this then become a 200Uf cap? Wouldn't it be easier to put in two quality 100uf pieces?
Thx
Dave
This morning I put my TU-879S on the workbench to swap in the Vcaps for C5 and C6. I removed C5 and tried to insert the lead on the Vcap into the hole in the PCB, but it won't fit. The 18 gauge leads on the Vcap are too large for the holes in the board. I did a pretty good job removing the old solder with solder braid, so I don't think that's the problem. I think the hole in the acrylic board is just a little too narrow.
Has anyone run into this before? Can I drill out the board without damaging the connection at the solder pad? How is this kind of problem normally dealt with?
Thanks
Bill
Has anyone run into this before? Can I drill out the board without damaging the connection at the solder pad? How is this kind of problem normally dealt with?
Thanks
Bill
I doubt it. I just replaced mine with vitaminq last fortnight. I think leads should be standard diameter. No problems with thickness of the leads versus hole diameter for me. Do not drill the pcb. Review the exact problem after a break or good nights sleep. You may have mistaken something.
G0bble
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Leads do not have a standard diameter, and neither do the holes in the circuit board. The leads on a 1/4W resistor are much narrower than the leads on the 100uF/400V caps that come with the kit, and the holes in the circuit board were drilled to match their respective lead diameters. There are several holes in the circuit board that will easily pass an 18 gauge wire, but the holes for C5 and C6 are not among them.
Manufacturers usually make leads thick enough so that a component can be stood up off the circuit with its own leads for better heat dissipation. Vcaps tend to be large and heavy so the leads are stronger than most.
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I finally got the V-Caps installed, here's what I did:
After doing some research on how manufacturers drill holes in printed circuit boards (they use carbide drill bits spinning at 35000rpm or higher) I went out and bought the closest consumer approximation I could find: the Dremel Moto-tool 4000 and a set of tiny bits (628-01) and matching collets (4485). It turned out that the 3/64" bit was the right size for the 18 guage. A sturdy drill press that takes the Dremel as an attachment would have been ideal, but Dremel's drill press has a reputation for inaccuracy, and I really wanted to get the job done without buying more tools. What I did was place the bit right on the hole in the PCB and then turn the Dremel on with the speed set to 10000 rpm. The drilling action smoothly drew the bit through, and I was left with a slightly larger hole and an undamaged solder pad. I completed the rest of the holes and soldered in the V-Caps without any further problems and the caps are now well into their break in period.
After doing some research on how manufacturers drill holes in printed circuit boards (they use carbide drill bits spinning at 35000rpm or higher) I went out and bought the closest consumer approximation I could find: the Dremel Moto-tool 4000 and a set of tiny bits (628-01) and matching collets (4485). It turned out that the 3/64" bit was the right size for the 18 guage. A sturdy drill press that takes the Dremel as an attachment would have been ideal, but Dremel's drill press has a reputation for inaccuracy, and I really wanted to get the job done without buying more tools. What I did was place the bit right on the hole in the PCB and then turn the Dremel on with the speed set to 10000 rpm. The drilling action smoothly drew the bit through, and I was left with a slightly larger hole and an undamaged solder pad. I completed the rest of the holes and soldered in the V-Caps without any further problems and the caps are now well into their break in period.
How did you manage to isolate an already assembled pcb for drilling? Didn't you have to clamp it down to prevent it from spinning at 10000 rpm with the drill? Did you remove it completely from the chassis by unsoldering all the wires?
PS: Let us know the sonic results. That is one last upgrade I want to try myself.
G0bble
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PS: Let us know the sonic results. That is one last upgrade I want to try myself.
G0bble
Sent from my GT-N7000 using Tapatalk
Hi Gobble,
The PCB was out of the chassis and I had already removed the previous caps, so I had a clear path to insert the Dremel from the top of the board. There was no need for clamping with a drill bit that small and moving that fast. When you have large drill bits moving slowly is when you run into problems with it spinning the workpiece.
I'll post on this thread when things have broken in long enough for me to make a judgment, but if you want to follow more frequent updates you can find them at this link on page 12.
The PCB was out of the chassis and I had already removed the previous caps, so I had a clear path to insert the Dremel from the top of the board. There was no need for clamping with a drill bit that small and moving that fast. When you have large drill bits moving slowly is when you run into problems with it spinning the workpiece.
I'll post on this thread when things have broken in long enough for me to make a judgment, but if you want to follow more frequent updates you can find them at this link on page 12.
Hi Gobble,
I'd like to give you a list of caps and a quick review of each, but I just don't have that information at this point. I'm really only starting on a series of cap experiments and it will be months before all the results are in. I'll be trying Mundorf Silver in Oil, Sprague Vitamin Q, and the Russian K75-10 and K75-24s. As of now, I don't have these in hand so I couldn't tell you if the leads fit or if the caps fit in the chassis.
Wasn't Victor selling the Vitamin Q? If so, I'm sure they fit and I would guess they sound very good. In another month I might be able to tell you about the sound from personal experience, but right now I don't know.
I'd like to give you a list of caps and a quick review of each, but I just don't have that information at this point. I'm really only starting on a series of cap experiments and it will be months before all the results are in. I'll be trying Mundorf Silver in Oil, Sprague Vitamin Q, and the Russian K75-10 and K75-24s. As of now, I don't have these in hand so I couldn't tell you if the leads fit or if the caps fit in the chassis.
Wasn't Victor selling the Vitamin Q? If so, I'm sure they fit and I would guess they sound very good. In another month I might be able to tell you about the sound from personal experience, but right now I don't know.
Gobble,
Sorry about the confusion, I've just been preoccupied with my coupling cap experiments. I am planning to try the ASC X386S as a power supply cap, but it doesn't have leads and absolutely will not fit in the chassis. I'm planning to hook mine up with wires. I'll try it in both the C15 and C13 positions and let everyone know the results.
Other than the ASC caps, I'm not sure what I could recommend in the power supply. This capacitor shootout ( The Great Capacitor Shoot-Out ) lists caps tested best for use in power supplies, so you may get some ideas from there.
Sorry about the confusion, I've just been preoccupied with my coupling cap experiments. I am planning to try the ASC X386S as a power supply cap, but it doesn't have leads and absolutely will not fit in the chassis. I'm planning to hook mine up with wires. I'll try it in both the C15 and C13 positions and let everyone know the results.
Other than the ASC caps, I'm not sure what I could recommend in the power supply. This capacitor shootout ( The Great Capacitor Shoot-Out ) lists caps tested best for use in power supplies, so you may get some ideas from there.
NP I'll wait for your reviews.
I just received the Genelax Gold Lion KT-66s today. Along with the Vitamin-Qs, and Psvane Treasure-II 12AX7 it has been a month of extraordinary upgrade nirvana. A killer upgrade all taken together. These tubes are THE Ones to go for. The amp now has such authority and presence, I could hide it in a beefy vintage tank like chassis and pretend it's a hulk. All without losing it's ability for reproducing sentimental music with the sensitivity and soul it has been rendered with. I am buying one more pair of these tubes as a backup.
G0bble
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I just received the Genelax Gold Lion KT-66s today. Along with the Vitamin-Qs, and Psvane Treasure-II 12AX7 it has been a month of extraordinary upgrade nirvana. A killer upgrade all taken together. These tubes are THE Ones to go for. The amp now has such authority and presence, I could hide it in a beefy vintage tank like chassis and pretend it's a hulk. All without losing it's ability for reproducing sentimental music with the sensitivity and soul it has been rendered with. I am buying one more pair of these tubes as a backup.
G0bble
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After my local Audio Guru examined the TU-879s Schematic he suggested to remove and bridge two of the last couppling caps C1 and C2. based on the less is more theory. I just upgraded to some tftf V-caps and even before the burn in improvments can be heard ( i also replace C13 with a better 100uf 650 v JJ cap it is impossibl to fit the large mundorf's, soloen or any 100uf 400v or > foil cap i can find without modification to the chassis or hanging it outside which does not seem right.. if any one out there has found another solution please let me know. unfortunately i think i got one of the last kits in Japan of this nice little Amp.
Whoa! Even before you asked, I was mulling over posting that this amp needs to be touted as a KT66 amp that can also play 6L6. They beat the 6L6 hands down. The presence came with the treasure-II 12AX7s.
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~G0bble
Sent from mobile, please excuse brevity and typos.
I aggree compaired to the EH 6L6 tubes that came with the kit the gold lion are a huge improvement however i am curently enjoying the vintage 6L6 GC tung sol (USA, RCA made?), in Japan a lot of people go for the Gold Lion KT88 perhaps for the power increase i have the KT77 but have really enjoyed the Vintage Tung Sol 6L6 GC with a 1962 telefunken 12 Ax7 looking forward to trying some vintage EL 34's and even the Gold Lion KT66. pretty amazing over most of the competition it is amazing that Electro Harmonix makes Gold lion! to me the beauty of the TU879 is that so many tubes work so well. i am only 100 hours into a v-cap burn in so time and a bit more money will tell. it is a delema, to upgrade the Amp to the TU 8200 of spend more on tubes ???
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