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Quick Overview

Very detailed and musical, packs a wall of punch.

***Single only****


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  • Ruby 6L6 GCMSTR


The Ruby 6L6GC-MSTR is from the Shuguang factory. It's thicker glass envelope and sturdy construction is designed to work in the most demanding applications. They are packed with lot's of punch and a sweet sweet tone, very musical. Philips STR-415 copy. This is the same tube Mesa relabel's as their STR-440's. Singles only, no matched sets.

Customer Reviews

Victoria Bandmaster Review by Mike
Doug's suggestion of the Rubies (assume rated @ 30watts) made the Bandmaster sound the best ever. Tube matching was perfect. They replaced poorly matched Sovtek 6L6GB's (assume rated @ 23watts) . Tubes were biased by cathode resistor method at 40ma with 450 plate voltage, target dissipation was 60% for Class AB fixed bias amp. Helpful bias links, and
Shipping was fast and packaged very well.
Thanks Doug (Posted on 6/20/18)
Best bang for your buck Review by Cam
I really hate to admit that you don't have to spend the most to get the best bulbs.....and I've been through a LOT.
These chinese tubes always sound clear and punchy in my amps and last and last.
Can't go wrong with these! (Posted on 8/20/17)
Peavey 5150 retube Review by Jeff
Just installed and played my Peavey 5150 with your recommendation of tubes for metal and it's incredible! Great sound great price! Thank you! Jeff Fahy, lead guitarist for recently signed Rock N Growl Records artist Soldiers Of Solace (Posted on 1/21/17)
Mesa Boogie Triple Rectifier Review by Tony

Just wanted to let you know I got the tubes I ordered from you today.

I popped them in and they sound completely amazing. It's tight, articulate and awesome.

Thanks so much! (Posted on 5/26/16)
Mesa Boogie MKV full retube Review by Bryan
Hey Doug,

I have been putting the Mesa Boogie Mark V through it's paces after installing the tube kit you recommended and provided me with. I wanted to take a moment to say thank you so much and also to just say WOW! The reason I bought the Mark V in the first place is because it was supposed to be like the "Swiss Army Knife" of amplifiers. But it ended up being a JEEP! An uncomfortable, rough riding and hard to control touchy pain in the arse that takes forever just to dial it in to a close enough setting. The cleans were ok but went from shimmer to ROAR with no in between. The gain stages in the crunch and lead channels were just too dark and muddy. Now....OMG! It's so expressive and articulate. Responds perfectly to every note. I spent a long time learning how to go into and out of every note of every chord cleanly and accurately. Now, I can hear my efforts so clearly and I am just thrilled. I have to say....I fell in love with those 7025s in the Channel 3 gain structure. I went with the high gain models fearing that there might be a bit too much hair but again WOW! You definitely know your tubes sir and how to match them up with the right amplifier. I am forever grateful that I happened to stumble across the source that said "Try Doug's Tubes." "They get it right there."

Thanks again Doug and looking forward to future purchases.

All the best to you.

Bryan (Posted on 6/13/15)
Egnater Tweaker 40 Review by Steve
Hello Doug,

I want to thank you for the excellent recommendation on replacement 6L6 tubes for the 40 watt Egnater. The Ruby 6L6GCMSTRs sound perfect. The two tubes were very closely matched and the resulting sound is really excellent.

The packing for shipment was solid and the box arrived quickly. Can't ask for more!

Steve K (Posted on 2/3/15)
Mesa Boogie Dual Rectifier Roadster full retube Review by Cameron
Played the amp last night for several hours after changing the tubes. I just wanted to thank you for putting together a great tube swap for a great amplifier. My Mesa Roadster sounds fantastic! It is very quite and has a very pure tone. I was able to really dial back on the gain and get some amazing tones with less noise. I'll be honest, I was a little hesitant to order non-Mesa tubes, but I'm glad I did! The reviews on forums and on your website can be believed and I'll order from you in the future. Thanks!

Cameron (Posted on 12/21/14)
Fender Bandmaster Review by Wayne
Got em! Love em! I can't wait to play out with my 'new' amp!

Thx for the advice, WB (Posted on 11/13/14)
Randall RT50H Review by Brian
These tubes really bring this head to life. Good gain, good warmth, and great punch! I just bought another set from Doug even though I'm not ready to swap yet just because I don't see any reason to go with anything else. Great tubes! (Posted on 3/24/14)
Mesa Boogie MKiii retube Review by Drew
Hi Doug,

These turned my old Boogie Mark III into a monster. Thanks again for more awesome tubes. Drew (Posted on 5/19/13)
Fender Twin Reverb Review by John
Hey Doug

I just installed the Rubies you sent me for my Fender Twin, just wanted to say thanks for the help is the best I have heard this amp sound since I owned it, is there a place to give a review to spread the word of your help and your products?


John (Posted on 5/11/13)
RUBY 6L6GCMSTR (4) Mesa/Boogie Roadster Review by Chris UK
Just retubed my amplifier and first impressions it sounds fantastic, a bit more tweaking and I`ll have it sounding amazing.

Recently fitted the preamp tone pack (6) coupled with the power tubes this amp now sounds excellent. Great gain tone, notees are clearly defined and with a wall of sound behind you, the leads are amazing singing.

Anybody reading this and are unsure about purchasing these tube kits, rest assured you`ll be amazed whatever style of music you play, I mainly play rock/metal so went with the recommended descriptions.

Thanks to Dougs Tubes (Posted on 5/9/13)
Peavey 6505+ Review by Simon
Thank you very much,
I installed my new tubes yesterday
Awesome, exactly what I was looking for!
Sound really great!

Best regards

Simon Guénette (Posted on 2/21/13)
Egnater Renegade retube(Ruby 6L6GCMSTR, Ruby EL34BSTR, 6 x 12AX7 tone kit) Review by Asa
The tonekit preamp tubes and the recomended power tubes sound amazing. I can't thank you guys enough. (Posted on 1/28/13)
Peavey Ultra retube(with the 4 x 12AX7 tone kit) Review by Jamey
So I finally got a chance to put in the new "tone kit" and power tubes today... and I must admit I was pretty skeptical that there would be a noticable difference. I am glad to say I was dead wrong! The clean channel is much more vibrant and lush with a really nice "fenderish" bite and lots of clean head room. The crunch channel sounds pretty much like it did before (which is a good thing because that was the best part of this amp), and now the "ultra" channel is MUCH more articulate... less muddy and just really freeeeeeking great. You da man. Please feel free to share my testimonial for all the other Peavey Ultra owners out there. You rock!!!!

Jamey D.
Black Market Lunchbox (Posted on 1/5/13)
Peavey Classic Duel 212 retube Review by Rick
What was recommended and purchased:
RUBY 6L6GCMSTR's and for the 12AX7's, a Tung-Sol in V1, a Sovtek LPS in the phase inverter and Ruby 7025SS's.


The tubes got here today, and I cant believe the difference!!!! Thank you so much!!!!

(Posted on 11/8/12)
Peavey Valveking VK100 Review by Tyler
The tubes sound beautiful, pretty much exactly what I was looking for. For the money, with a small investment in tubes, I am very pleased with it. Also very pleased with your service and will recommend you to anyone I know needing tubes. Thanks again!
(Posted on 11/5/12)
Sansui AU-111 stereo amp from late 60's, (Ruby 6L6GCMSTR's matched quad) review. Review by Steve
I wanted to bring this amp back to the unmatched quality and tone range as when new. These tubes have done that in spades. Seems to have perfect tone balance and really spectacular headroom. I installed these tubes after a complete rebuild of all capacitors and many non-precision resistors, etc. Amp is absolutely dead quiet at full volume with no input. Thanks Doug for your recommendation that I go with these tubes. (Posted on 9/2/12)
Carvin X100B retube(RUBY 6L6GCMSTR's, Ruby AC5 HG+ in V1, Ruby 7025SS in V2 then a Sovek LPS in V3) Review by Tim
The tubes rock!!! Thanks so much!! You saved me a lot of money!! (Posted on 8/17/12)

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