Tube substitutes

Wed Feb 18, 2015 3:01 pm

Need you to share your experience with tube substitutes.

I have had a Fender Blues Deluxe 40 watt for years and while I am primarily a Boogie fan this amp has it's place, but it has a notoriously loud jump after about 3 on the volume knob. Many attempts to tame the volume and gain include a ebay volume box (decent basic attenuator that drops volume but colors the tone some), Weber MiniMass (have issues connecting but could be due to triode pentode switch), Yellow Jackets (EL84 tubes that drop it to about 17 watts and cool EL tones), Andrews amp lab put in a triode pentode switch that can drop it to about 20 watts (great mod but still has big jump at 3), and now some tube changes.

After reading various Bill M mods for Blues Jr and Blues Deluxe these tame the gain pretty well. Standard tubes are 2 6L6 and 3 12AX7, I switched valve 1 with a JJ2AT7 and I like the tone a lot. Just put in a Electro Harmonix 12AY7 in valve 1 and 3 will see what this does tonight.

Have anyone here tried these with a Blues Deluxe or Blues Jr, and what did you think?

Re: Tube substitutes

Wed Feb 18, 2015 3:26 pm

Sam, I have done the same experimenting with the V1 in another amp. The 12AX7 is a higher gain and the 12AT or 12Ay are less gain. When changing the preamp tubes I think you will notice tone changes more than with output tubes but that is just my opinion. I would think the preamp would give better control over the overall gain than the output. I also like the tone when I changed the preamp tube type. I have not used a BJ amp. -- Darwin

Re: Tube substitutes

Wed Feb 18, 2015 7:24 pm

I would love to hear how this works out for you. I have a Blues Deluxe and am waiting for an attenuator I bought online. I'm hoping it'll do the trick without messing with the tone too much. But if it doesn't, I would like options to keep the volume to reasonable bedroom practice levels.

Re: Tube substitutes

Fri Feb 20, 2015 5:47 am

Darwin you always have experience we can rely on! :thumbup: Yep, the output is really not affected, maybe the tone has made it appear so. For the Blues Deluxe a lower gain tube is better to my ears.

Nubs, I got the 12AY7's in but no chance to really play and hear. I will give it a try tonight. After that, I will try a 12AY7 in V3 and the 12 AT7 in V1. In a thread I researched, this was the preferred set up by the poster. I am just trying to hear all options at this point, will let you know.

Re: Tube substitutes

Fri Feb 20, 2015 6:56 am

Sam your plan sounds good to me. That may give you less headroom also, Lower gain can result in sweeter tone. -- Darwin

Re: Tube substitutes

Sat Feb 21, 2015 10:08 pm

Try a 5751 JAN for the V1 stage. Slightly lower gain than the 12AX7.

Re: Tube substitutes

Sat Feb 21, 2015 11:43 pm

csveteran thanks, may give that a try. Both options I'm trying now are an improvement, kind of a toss up on a preference between the two, need more play time to really tell.

Re: Tube substitutes

Sun Feb 22, 2015 5:50 am

I have a 5751 in my Deluxe Reverb input stage, and like it. It's NOT dirtier than a 12AX7, it has slightly less gain (which just means, for me at least, running the knob one number higher than before, no problem) but its main significance for me it that it is much less noisy. Admittedly, it is an expensive one (a G.E.) but I was so fed up with my noise level I gambled, and found I won.
I'm not actually using the amp for crunch much at all, that's being done by a modified Kingsley Juggler, adapted to work at amp input level, and with a simple bass-restoring mod of mine to the output of the Overdrive circuit. Very Dumble, loving it. The amp just tubes things up a little bit more when it's loud, and that's nice.
On Fender amps with two input channels (such as mine, twins etc) I like removing the input valve from the non-vibrato input (which then becomes inactive). This is usually "V1" in Fenders. The result of this is to throw the bias of the Vibrato channel's input valve off-spec, but in a good way. By design, the two input valves share a bias resistor, and removing one changes the bias on the remaining one. Urban myth says that this was a Cezar Diaz / SRV mod, but who knows? I like it, though.

Re: Tube substitutes

Wed Mar 04, 2015 7:33 am

Well campers my tube testing is complete and the results are in for pre amp tubes in my Fender Blues Deluxe.

Below are options tried including original tube set up:
Original = 3 Fender (Sovtec) 12AX7 - higher gain and more noise than I care for, especially for a "blues" amp, needed to be tamed in many ways

Option 1 = V1 JJ12AT7, V2 Fender (Sovtec) 12AX7, V3 Fender (Sovtec) 12AX7 - reduction in gain, volume and sparkle. I did like this at first but was unsure about the big drop in gain

Option 2 = V1 Electro Harmonix 12AY7, V2 12AX7, V3 Electro Harmonix 12AY7 - two 12AY7's has about half the gain of a 12AX7 which let me turn up the volume and drive tubes before break up starts, warmer better sound

Option 3 = V1 JJ12AT7 , V2 12AX7, V3 Electro Harmonix 12AY7 - better than option 1. still has a volume drop but better clarity.

Option 4 = V1 JJ 5751 (Cryoset), V2 12AX7, V3 Electro Harmonix 12AY7 - all the clarity, break at about 5 on the volume knob and enough gain to give drive

Favorite options
1. Option 4 with 5751 with 12AY7 is my favorite from these options. Allows me to drive the tubes and maintain balanced tone overall. CSVeteran and NICK are obviously in the know on the 5751 tube selection.
2. Option 3 with 12AT7 and 12AY7 reduces gain significantly, so for a straight blues to clean country amp with lowest gain this would work for me. The only warning sign was the 12AT7 ran hotter than the other tubes, don't know what this would amount to but it did catch my attention.
3. Option 2 with two 12AY7s would work any day but I thought the others gave a little more tone character

Who knows I may try another option later but 5751-12AX7-12AY7 will be my set up for a while. (No preference for the Cryo tube, just found one for a decent price and wanted to see how it sounds) Next may try Tung Sols, JAN Philips, GE's or some other maker as well. All you Blues Deluxe owners these may work for you. I found that controlling volume by the guitar volume knob versus amp volume I could do more with this amp.

As always YMMV :lolno:

Re: Tube substitutes

Wed Mar 04, 2015 9:38 am

I've been waiting for your results. I'm glad to hear that your liking your amp better! I've been playing the tube swap game with my '71 Princeton Reverb. It started to breakup at 3 and the overdriven tone was buzzy and not at all pleasant sounding. My first swap was to replace the RCA 6V6 power tubes with a set of Japanese made Motorola 6V6 tubes. This made a big difference but I still wasn't satisfied. Next I went after the V1 tube. I removed the RCA 12AX7 and replaced it with a NOS RCA 12AY7 tube. This took a lot of the gain out of the amp and mellowed it out. Now it's clean and loud up to 6 on the volume knob. The overdriven tones are natural and smooth sounding now! The amp is really big sounding when I run it through my 1x12" Bogner cabinet. I went from ready to trade the amp to being a very happy camper!

Re: Tube substitutes

Sat Mar 07, 2015 4:31 pm

Sam - another tube I am fond of in both audiophile and guitar amp applications (although not lower gain), is the Amperex 7025 for the V1 stage. The NOS European "Globe" logos and ones made in Hicksville, New York are my favorites. Amperex also made a *PQ* 7025 (premium quality) version that was one of the best sounding production 12AX7s ever made. Clean, warm and bright best describes it. Incidentally, I have some GE JAN 5751s that are still up and running after 25 years, which attests to its durability and rugged construction. Warm sounding and bullet proof for gigging musicians.

Re: Tube substitutes

Thu Mar 26, 2015 7:46 am

hi guys, i went looking for some valves i had put away long ago before i was interested in valve amps and found these Japanese made pre amp tubes and a power tube. Does anybody have experience with these Hitachi, Toshiba and NEC tubes. Any idea of what year they might be and if they sound any good tone wise.
http://s1381.photobucket.com/user/Geoff ... l.jpg.html
http://s1381.photobucket.com/user/Geoff ... g.html?o=0
Thanks
Geoff

Re: Tube substitutes

Sat Mar 28, 2015 4:07 am

I cant find much information at all about these tubes but for anyone who's interested in pre-amp tubes this thread has quite a bit of information,
http://www.thegearpage.net/board/showth ... p?t=460307
cheers