Replacing output caps

[Mechnutt]

For anyone needing to replace the Jensen Paper-Oil Aluminum caps in their BAT preamp, you can buy them for about $20 per cap (as opposed to $75 per cap) direct from Jensen in Denmark with 3 day shipping. I replaced all 12 output caps in the six packs of my VK-51se preamp. I had a friend do the job for me. It saved me $600. The difference in sound was very apparent. The dynamics are better, bass is deeper and tighter and the overall clarity has improved. I have about 30hrs on the caps so far and the sound keeps improving. The first 15 hours was rough sounding.

BAT claimed the original Jensen caps had a higher failure rate but they have not seen a failure in the newer caps. My preamp was making a popping noise when switching inputs or turning off the preamp.

[Btselect]

The cap used by BAT is the tinned copper lead out wire version there is also a silver lead out wire version which I prefer with better performance, and which all of their higher end caps use. As to the newer caps, to my knowledge they are still built the same way the only difference is upon request they will put epoxy to the ends which seems to solve the leaking problem. If your caps didn't have the epoxy ends or even if they do, I would still recommend using fans to reduce the internal temperature and extend component life, I use the Noctua NF-A15 fans. The potential of the 51se and the 31se is tremendous, its the last of their preamps that have a huge power supply using both electrolytic and oil filled capacitors, and the degree of improvement depends on the quality of these caps that are used.

[joeinid]

Welcome to the forum Btselect, thank you for joining.

[Mechnutt]

All the caps that I replaced tested their appropriate voltage but clearly some were bad as the popping sound when changing inputs or turning off the unit has been rectified. In addition, the sound is much improved. It is more musical, dynamic and smoother sounding. Low volume listening is much better too. The music has a fuller sound with a thicker midrange. Bass was great before but now it hits harder. I am truly amazed at the difference in sound. My electrical engineer friend says that the caps tested well but it was they way they were discharging that was bad. That certainly makes sense since the sound is much more powerful and dynamic.

My listening room is fairly cool. We keep it at 69-70 degrees year round but I have thought about using a fan on the preamp. As for the newer caps lasting longer, I was quoting what Mr. VK himself told me. Whether it is true or not, that is a different story but I take him at his word. It was interesting to note that they charge $900 for the parts and free labor to replace all the caps. I paid $279 for the parts and shipping from Denmark.

[tac54]

The caps in my VK-51SE were replaced in June of 2011 for $900 and i love the preamp, i was going to sell it since i have the integrated amp now and work is slow. But reading what Btselect said about the transfomer i want to keep it and maybe sell one of the motorcycles instead. The Bat is alot safer.

[Mechnutt]

The caps in my VK-51SE were replaced in June of 2011 for $900 and i love the preamp, i was going to sell it since i have the integrated amp now and work is slow. But reading what Btselect said about the transfomer i want to keep it and maybe sell one of the motorcycles instead. The Bat is alot safer.

Welcome To AS!
Did you notice an improvement in sound with the new caps?

[tac54]

Hellow Mechnutt and Thanks, the caps were replaced by the previous owner shortly before i bought it. He sent the work order with it. Are the newest caps a different color? I believe the newer super pak caps in the Bat cd player are black and the first versions are silver. Or i could have that backwards? I had a VK-31 non se that would make a snap as you descibed but i was using the rca outs, cant remember but i changed ics and it stopped. It was new open box when i bought it. Liked that pre very much also. My biggest mistake was selling my VK-D5SE the 20 bit, havent heard a bunch or different cd players but i liked that one the best by far. Ted

[Mechnutt]

The Caps in tbe BAT Vk-51se are orange-yellow 400V 1uF by Jensen from Denmark. The new ones are the same color.

Here is a picture of the inside. The Six Packs are the 2 stacks of Yellow-Orange Caps on each side of the back of the unit.

Balanced Audio Technology VK-51SE line preamplifier | Stereophile.com

[tac54]

So the non se pre amps have the six-pac also just less of them and 6922 tubes instead of the 6h30? The invoice says DC output >2.0V, replace SIX-PAK oil capacitors. DC output after replacement <60mV. I guess i thought just the SE models had the six pak. Thanks

[johndoe21ro]

For anyone needing to replace the Jensen Paper-Oil Aluminum caps in their BAT preamp, you can buy them for about $20 per cap (as opposed to $75 per cap) direct from Jensen in Denmark with 3 day shipping. I replaced all 12 output caps in the six packs of my VK-51se preamp. I had a friend do the job for me. It saved me $600. The difference in sound was very apparent. The dynamics are better, bass is deeper and tighter and the overall clarity has improved. I have about 30hrs on the caps so far and the sound keeps improving. The first 15 hours was rough sounding.

BAT claimed the original Jensen caps had a higher failure rate but they have not seen a failure in the newer caps. My preamp was making a popping noise when switching inputs or turning off the preamp.

Very useful info, Mechnutt! Thanks a lot!

[absinthe123]

I have a crackling sound coming from my Watt Puppy 7 speakers. I was told the problem was My BAT VK51SE preamp. My technician wants to replace all caps on the capacitors. Does this sound like a possible solution. I had all tubes replaced a while ago by a different tech. and that didn't work.

[joeinid]

Welcome to the forum, thank you for joining.

[aKnyght]

I have a crackling sound coming from my Watt Puppy 7 speakers. I was told the problem was My BAT VK51SE preamp. My technician wants to replace all caps on the capacitors. Does this sound like a possible solution. I had all tubes replaced a while ago by a different tech. and that didn't work.

really does sound like a noisy tube somewhere, especially if the noise is intermittent. probably worth at least double checking all the tubes (sequentially, one at a time) in your system before proceeding to major surgery.

if you have a tube amplifier, the signal/driver and output tubes there could also be the source. tube phonostage?

at least that way you know it is not a common issue with an inexpensive fix before proceeding.

[Speedskater]

Typically it's only electrolytic capacitors that go bad. If they are in the power supply then the hum level will increase. If they are coupling caps then the bass response will diminish.

[Mechnutt]

I have a crackling sound coming from my Watt Puppy 7 speakers. I was told the problem was My BAT VK51SE preamp. My technician wants to replace all caps on the capacitors. Does this sound like a possible solution. I had all tubes replaced a while ago by a different tech. and that didn't work.

I have the 51se and the first sign that the 12 6 pack caps were going bad was that when I would change the input using the front buttons or if I were to turn the preamp off, I would get a loud pop through the speakers. There was never any hum. I spoke with Victor Khomenko from BAT and he said it was the caps and that the original Jensen Caps were defective and wore out prematurely, but the newer ones don't have this problem. He stated that they would replace all the caps for $900 (the labor is free).
I bought my caps direct from Jensen for $260 and had an EE friend replace them for me. Parts Connexion also sells the caps.

http://jensencapacitors.com/products.aspx

If I were you, I would call or email BAT and ask them if your issue is related to the caps. Be aware that if you replace the caps, the preamp will sound bright and rough for about the first 100-150 hours. I thought I ruined the BAT after replacing the caps but it sounds better than ever now.

Larry