Pop Pop - Not Rickie Lee Jones

[JackD201]

I had a free day today so I figured I'd get my bedroom system up and running. I've been running hybrid amplification for my main system for quite some time now so I figured I'd dip into my old equipment stash and set up an all tube system. The Unifield 1 monitors are set to be delivered so my personal pair of Unifield 3s, like the ones attempting to tide Mike over until his MM7s arrive, got pressed into now permanent service. I also finally put them on the custom U3 stands made by Solid Tech.

I pulled a back muscle (must remember to warm up and stretch before playing, my age is showing ) but fortunately both drivers were around to lend some muscle. The whole time we were setting up the CMS Sapphire amp bases and laying out the cables, I kept wondering if some failure would happen with the amps being in storage for so long. These amps had been sold before but had somehow found their way back to me. As such, I had no idea about the source and state of the 6c33s. I first purchased these amps in 2004. They are BAT VK-150s which are basically a pair of VK-75s that are single ended bridge paralleled producing 150wpc. These were my main amps until I switched to the Lamm hybrids.

Before powering up, old memories came back to me. The optimist that I am, I was remembering how much I loved the midrange these amps provided when I used VR-4 SRs and later VR-5s. I also remembered how I wanted more control down below and my failed attempt to mate them in bi-amp with my Levinson amps at the time hence my switch to hybrids. As I switched them on, images of fuses blowing came back to me and with it came some tense moments. Would the green LEDs for each tube go on? The tubes began to light up then moments later.....Click, click, click, click. Whew! Now for the other one. Click, click, click, click. Yahoo!!!!!!!!

I took the next few minutes to do a bit of cable dressing and to give the amps more time to stabilize. Then I hit play. Ahhhh. Effortless sound. The U3 is a pretty light load. Normally I run them with only 50wpc mono blocks. I had plopped the speakers down where they usually go and they were giving the same predictable results. I was thoroughly enjoying myself and 9 tracks in, it happened.

Pop. Pop.

Fortunately it's daytime here. B+ fuses blowing in a dark room can look like a lilliputian Thor was throwing a bachelor party inside your amplifier. Not a pretty sight. Bad tubes, not one but two. It could have been one but it likely took its parallel auto bias partner with it hence the two dead green LEDs. I then remembered Mep and his wrestling with his Defy 7s. The fuses are on the bottom plate of the amplifier. A bit of a bee-yotch considering these amps are luge sized and heavy. Fortunately, the service of the local BAT distributor is top notch. It won't take very long until I get a complete set of replacement tubes and fuses. I could have saved a little by ordering from a tube store but I know that the two that blew were not from my original BAT supplied stash. I know because I number them.

So I guess I'll just have to wait it out. I ordered a pair of KR Audio DXs maybe these will arrive first. Damn. Tube amps can be a pain in the ass. I wish they didn't sound so good.

 

[Bill Hart]

Jack, isn't that the same big dimpled Russian power tube that Vlad uses in the ML2?
So, the moral of the story is that these tubes worked when you last had the amps running 8 years ago, and that they 'went bad' by sitting idle? That doesn't bode well for NOS tubes, does it? Any chance (not wishing this on you) that something in the circuits (another part or wire) went south after that long hiatus, and that's what caused the fuses and tubes to go? In other words, does it make sense to have the amps gone over completely while they are down so you don't have a repeat performance once you install the new tubes and fuses?
I seem to remember people using Variacs to bring long idle equipment back up to power, but I'm not sure if that has any applicability here....
Guess you should use that RLJ album to fire them up (no pun) once you get them going again.

 

[JackD201]

Hi Bill,

The funny thing is the ones that blew aren't the original ones They didn't have my markings which correspond to specific sockets so I can keep track. These must have been put in by my friend who bought them from me. I took them off his wife's hands when he passed away suddenly as a way of helping out. That was how they found their way back to me. He was a good guy. Funny as hell but couldn't keep away from sweets, not a good thing for a diabetic.

I've had 2 tubes go before but in other V positions but I always sourced tubes from BAT. Change of tube and then they were A ok, the remainder still are. Keith has ML2.1s he's also had 6c33s sourced elsewhere that failed pretty quickly compared to those sourced from Lamm where only one has failed in 4 years or so. I'm a bit worried about what's on the open market now and would rather get from the preselected tubes from the manufacturers. So I'm getting tubes for these from BAT. I do have spare ML1.1 tubes but these are for my those. Vlad likewise marks tubes for specific positions. I don't know anybody with a tube tester that does 6c33s. In any case, you are right. I should have them checked out. I'll have some time before the tubes come anyway.

SAd thing is they were sounding reaaaaally good before, well, Pop and Pop happened. Rats!

 

[flez007]

That´s the cover charge one needs to pay owning tubes Jack (you surely know that by now).. worths the extra maintenance IMO.

 

[JackD201]

Yeah, I know bro. It's the down time that bugs me. If they were in my main system, I'd probably go nuts. These VKs hold a lot of sentimental value for me. I never wanted to sell them in the first place but my buddy wanted them bad and they were just in their boxes at the warehouse. In my old place I could only fit a pair of monitors and an integrated amp in the bedroom. I'm determined to get them back in shape.

 

[mep]

Jack-You have my sympathy. These are the kinds of things that can drive you over the edge with dealing with tubes. Numerous times in the past I got ‘mad’ at tube amps because of their unreliability and the anguish they cause when they break and I went SS, but it never stuck until the KSA-250.

The Jadis Defy 7 was just maddening to even check the bias when the amp was working correctly and not eating output tubes. Flipping a 100 lb amp on its side, taking all the screws out of the bottom plate and removing it, just so you could clip in your ground lead and start probing the bias check points is pure nonsense. Having one bias pot for each bank of 3 output tubes which requires the output tubes to be matched super tight (which is hard enough to do with a pair of tubes let alone three of them) is also not cool.

My last attempt to switch back to tubes didn’t go so well (and usually it is the other way). As much as I like the ARC VS115-and it is clearly the best ARC amp I have ever owned, I would still rather have the KSA-250 in my system. I have to admit that I thought about reinserting the VS115 into my system a couple of times just to reaffirm my decision, but when I think about moving the 140 lb KSA-250 off the amp stand in order to install the 65 lb VS115 which I know doesn’t have close to the same output power, bass response, or top to bottom authority, I kind of blow it off.

 

[Bill Hart]

Jack-You have my sympathy. These are the kinds of things that can drive you over the edge with dealing with tubes. Numerous times in the past I got ‘mad’ at tube amps because of their unreliability and the anguish they cause when they break and I went SS, but it never stuck until the KSA-250.

The Jadis Defy 7 was just maddening to even check the bias when the amp was working correctly and not eating output tubes. Flipping a 100 lb amp on its side, taking all the screws out of the bottom plate and removing it, just so you could clip in your ground lead and start probing the bias check points is pure nonsense. Having one bias pot for each bank of 3 output tubes which requires the output tubes to be matched super tight (which is hard enough to do with a pair of tubes let alone three of them) is also not cool.

My last attempt to switch back to tubes didn’t go so well (and usually it is the other way). As much as I like the ARC VS115-and it is clearly the best ARC amp I have ever owned, I would still rather have the KSA-250 in my system. I have to admit that I thought about reinserting the VS115 into my system a couple of times just to reaffirm my decision, but when I think about moving the 140 lb KSA-250 off the amp stand in order to install the 65 lb VS115 which I know doesn’t have close to the same output power, bass response, or top to bottom authority, I kind of blow it off.

MEP~ the french are known to be difficult sometimes....

 

[mep]

MEP~ the french are known to be difficult sometimes....

I get that, but I think that ARC tried to out-French the French with their VT-100 series of amps. If you want a good laugh (or cry if you own this amp), read the instructions on how to set the bias.

 

[Bill Hart]

I get that, but I think that ARC tried to out-French the French with their VT-100 series of amps. If you want a good laugh (or cry if you own this amp), read the instructions on how to set the bias.

Do the test points involve using a probe in the shape of a 1/4" phono plug? That's how my old D 75a is set up, I have the instructions, such as they were. That's much older amp, though.

 

[mep]

Do the test points involve using a probe in the shape of a 1/4" phono plug? That's how my old D 75a is set up, I have the instructions, such as they were. That's much older amp, though.

Nope. Your old D-75 amp was a walk in the park to set the bias compared with the VT-100 series of amps. The bias scheme is so wacky that Kevin Deal refuses to sell replacement tubes for the VT-100 series of amps. You have to take not only the top of the amp off, you have to remove the side pieces as well. And that is only the beginning of the nonsense.

 

[Bill Hart]

Nope. Your old D-75 amp was a walk in the park to set the bias compared with the VT-100 series of amps. The bias scheme is so wacky that Kevin Deal refuses to sell replacement tubes for the VT-100 series of amps. You have to take not only the top of the amp off, you have to remove the side pieces as well. And that is only the beginning of the nonsense.

Well, you know those Minnesotans are known to be difficult sometimes.
FWIW, I went to the opening of Fargo at the Stockholm film festival years ago. Nobody laughed (except me).