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Seeking Replacement Tube Advice


AnalogWave

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I’m the second owner of a Luxman LV-105u hybrid integrated amp which runs two 6CG7 tubes. The amp is 15 – 20 years old and the tubes are factory originals. I really like the amp’s sound through my Forte II but can’t help thinking it would sound even better with new tubes.

I’ve not opened it up yet, but I found this interesting (if somewhat over my head) bit of info from the aforementioned link...

The tubes are original NEC, which are well known for their long life, and measure at 87-90%, however they could be replaced with a pair of Ei 6FQ7 tubes. Although not the highest in gain, being the only maker of actual NEW 6FQ7s in an ex-military facility with very accurate equipment, their tubes have a slightly higher plate current rating, and more importantly, near perfect matching between the two triodes, a most desirable characteristic for this amplifier. Triodes have predominantly second order distortion, and the differential arrangement used in this amp has the ability to cancel out this type of distortion, as long as the two triodes in the differential circuit are well matched. The better the match, the lower the distortion. Ei tubes also tend to be reasonably priced which certainly helps!

I don’t have much to compare the amp to but the general opinion is the bass could be tighter. I haven’t found a great selection of 6CG7 tubes so basically I’m looking at these two RCAs and one Ei as replacements…

http://www.tubedepot.com/nos-6cg7-rca.html

http://www.tubedepot.com/bsct-6cg7-rca-ct.html

http://www.tubedepot.com/ei-6fq7eg.html

The amp is a bit of an oddball, so I’m just looking for input on tube characteristics from those who’ve run these. $150/pair is no biggie if they truly are superior but I'm leaning against buying/rolling all three since that would amount to more than what I paid for the amp.

With regard to my Fortes, they are 1996 factory-stock and I plan on upgrading the x-overs and possibly the tweeters to Ti diaphragms in the future when funds allow.

Thx for your time & help.

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I don't know if this will help but here's the USA distributor for Luxman: http://www.onahighernote.com/luxman/ It might be worth a phone call, pre-amp tubes can be problematic in some applications.

Thanx, Russ

P.S. I take some heat on this but I've had the best luck when I get my replacement tubes from the manufacturer of the equipment. They know what works best. Don't get me wrong, that's not the only way to get tubes, but if you want plug and play without too much hassle that's the way to go (if possible).

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From Brent Jesee's web site.......http://www.audiotubes.com/audtube.htm

6CG7/6FQ7 Mullard and Mullard made, and Amperex made.

New Old Stock in original box. Difficult to find these in the USA. These are from Mullard UK, and also the Mullard/Philips Hearndon works in Australia. Fine European version of this dual triode. The Amperex are Holland made.

25.00

3

6CG7/6FQ7 RCA cleartop, side mounted getterMATCHED PAIRS

New Old Stock in whiteboxes and original boxes. Choice of audiophiles. These have low microphonics and a great sound.....getting scarce. A few have labels smeared off but the tubes are NOS and fully guaranteed. These pairs are hand selected and matched to within 5 percent Gm, and are by far the best 6CG7 tube for the cost.

$48.00 per pair

20 pairs

6CG7/6FQ7 RCA cleartop, side mounted getter.

New Old Stock in whiteboxes and original boxes. Choice of audiophiles. These have low microphonics and a great sound.....getting scarce. A few have labels smeared off but the tubes are NOS and fully guaranteed.

$20.00

31

6CG7/6FQ7 Various USA made NOS blackplate.

New Old Stock in whiteboxes and original boxes. Choice of audiophiles. The 1950s blackplate versions of this tube are very rare. These have low microphonics and a great sound. Brands include RCA, Sylvania, Tung Sol, and others. MATCHED PAIRS, WHEN AVAILABLE, ARE $70.00 PER PAIR.

$27.00

1

6CG7/6FQ7 various USA brands, including military stock.

New Old Stock Original Box and whiteboxed. All vintage USA, much better than any current production tubes. Some military stock in original military boxes, $35.00 per matched pair.

$11.00

20

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