Today I went to my friends' house and videoed my Epiphone Valve Junior version 3 with 3 different preamp tubes-the stock 12ax7, 12at7 and a 12ay7-the latter was the most dramatic difference. Next in this series will be after Randy Landry of Lone Wolf mods it for me, and I'll video it in the same postion with the same mics and harp.
---------- Todd L. Greene, V.P.
Last Edited by on Feb 13, 2010 7:33 PM
Thanks, jon. Oh yes-12ay7 is the tube I will use until I can get the amp to Randy Landry for a mod. Also, that's the stock Eminence smooth-cone speaker. i don't dislike it, but I'll withhold my opinion until Randy goes thru it and changes some guts, giving it more bottom end. ---------- Todd L. Greene, V.P.
cost-wise for you, considering the shipping, i think you'd be better off hiring a decent electronics fiddler to follow his instructions that are on his site. He only lives 45 minutes from me, so it's an easy drive, otherwise I'd do the same. ---------- Todd L. Greene, V.P.
Last Edited by on Feb 13, 2010 7:57 PM
You should venture down to Baltimore for a day Jon I can help you with the Mod. I may even have most of the components leftover from my last Electronics shop run
Todd, When Randy gets done you'll move back to the 12ax7 and it'll be a warmer break up not quite as harsh but lots of muley kick to it. These lil 5 watters are fun. I used to link a combo and a head & cab on stage both modded. I thinned the herd and sold the combo. I like the 12 Eminence Lady Luck. Wish I had a decent cam ----------
The Original Downtown Philadelphia Fatman... Accept No substitutes!
Nice videos Todd! The 12AY7 is tonally better than the others for sure. It's the preamp tube I always use in my amps.
Last Edited by on Feb 14, 2010 12:25 AM
Nice demo's. If you can get a nice triple mica 6829, 6211 or 5814A; give them a try. These are all milspec/industrial grade, and can often be picked up for much less than any 12A's. The 6829 is classed as a 12AT7, but VERY smooth at 47 mu. The 6211 is a 27mu computer tube, so very AY sounding. The 5814A is rated as a 12AU7, but because of the lo-microphonics, sounds more like a top-o-line 12AY7.
Some 5965's ( 12AV7 variant ) can be good too, but some are noisy.
Can't go too wrong with any 12AY7, though. I have Sylvania LBP's 1953 that I use with my big amp.
For now, of the tubes I have, the 12ay7 is the winner. Once the mods are done, though, it'll have a 12ax7 again. All the harshness we swap tubes to avoid should be a thing of the past. We will see! ---------- Todd L. Greene, V.P.
It was a little still camera with video capabilities-nothing fancy, but better than what I have. A decent video camera with good audio is on my wishlist. ---------- Todd L. Greene, V.P.
One thing I never asked anyone, or have heard of, is if there is a discernable difference in the stock EL84 and 12ax7 tubes(mine has ElectroHarmonix for both)vs. 'upgrades' to tubes of the same value, i.e. Mullards, Jans, etc.? Is it worth the money? ---------- Todd L Greene. V.P.
Todd and friends, I got my electro-harmonix 12ay7 for my epivalve jr combo today. My epi had a jj 832 in it (who knew!) and the 12ay7 sounds so much better. I have to turn the volume knob much lower now but it sounds a thousand times more like I felt the valve jr should sound. Thanks Todd for the comparison. the best 16 bucks I've ever spent!
Do you notice the amp is less feedback prone as well, yes? Maybe you can get it even louder than with the 12AX7 without battling feedback? The effect isn't as pronounced in single tube preamp amps like the EPI as it is in 3-tube preamp amps like the Fender Bassman and all its derivatives - but it should make a difference.
Here are the relative gain factors of these tubes. You didn't try an AV or AU but since the AV is the lowest gain tube you've tried and you like it the best, you might find going even further is even better. You MIGHT. Easy enough to try.
GAIN FACTOR 100: 12AX7 - aka ECC83, 7025, ECC803, E83CC, 6681 GAIN FACTOR 70: 5751 GAIN FACTOR 60: 12AT7 - aka ECC81, 6201, 6679, 6829 GAIN FACTOR 45: 12AY7 - aka 6072, 6211 GAIN FACTOR 41: 12AV7 - aka 5965 GAIN FACTOR 19: 12AU7 - aka ECC82, 5963, 5814, 6189 ---------- /Greg
You are quite welcome Daz. Greg, I have a 12au7, but honestly I was worried about bringing the gain factor so low that it would damage the amp, so I didn't try it.
Should be getting my Epi modded this weekend by Randy Landy, so it will be running a 12ax7 again. I can't wait to hear the difference! ---------- Todd L Greene. V.P.
Greg-for now, I won't go any lower than the 12ay7. Hopefully getting with Randy Landry this week/weekend to mod it, and then it'll go back to a 12ax7. The 12ay7 has been a good temporary fix for it, however. I'm anxious for the much-needed treble cut to be added! ---------- Todd L Greene. V.P.
Wow, great vids! Yeah, that last tube swap sounded pretty damn good! I also liked the SM57 the best, for some reason. It sounded rounder, fuller, and less harsh to me...
Thanks for doing this Todd, it's VERY informative!
Not to stray too far for the original post...but I got my Epi Valve Jr. about 2 months ago. I get my best sound from an idea I got from a post from Adam. I take my Bottle o Blues mic into a Boss M20 multi effects unit. I basically use that for the EQ and occasionally some echo. I then use the stereo out and have one feed going to my Valve Jr and the other to a Peavey Backstage solid state amp with Reverb. The two together really fill the room with a nice wall of sound. Adam does this with a tube and solid state amp as well.
Just put a 12AT7 (and also an upgraded el84) in my new valve junior head - has made a great improvement to my ears. Volume can now go up to '10:30' (if you look at it as an hour hand on a clock) before feedback comes in, and by that point it's giving a nicer distortion, horn-like and not too trebly. There wasn't a great choice of 12AY7s where I was looking (UK), and the east german NOS valve I got from watford valves came recommended as being particularly good for harp. Will try a 12AY7 in time I'm sure, but will gig with this for now. Incidentally, the valve changes also improve the amp for guitar, in my opinion, overdrive more musical, string separation better.
So I don't get it, whats wrong with the 12AT7 for the epiphone valve jr? I just got the half stack and just ordered the at7! Yikes, should I have gotten the au7? I am trying to get max volume from this thing, I am to be using this to gig. I'm using a super hot shure 425 commando mic. Did I get the wrong tube?
Oh, and the place that I ordered from had a comment box where I told them I wanted my el84's to be max headroom at high volumes with late breakup... They said I can request early distorting tubes or later distorting ones and I chose later, thats what I need for harp, right?
Smokey, I'd like to know the answer to that early/late breakup question too, although I'd opt for 'late breakup', using my high school-era multiple guess strategy.
On the 12at7 question-I didn't notice a tremendous difference until I dropped the 12ay7 in(notice the gain percentages in Greg's table above). Your experience may vary due to tube make. My 12at7 was an old MILSPEC one. I don't think there is anything 'wrong' with using one-you may be thrilled with it.
Although I dig the portability of my combo, hindsight being what it is, i would have gotten the head/cab halfstack-that 12" adds sweet bottom end.
I've got to find the time to do Part 4 with my now-modded Epi. HUGE difference, and it's ridin' fine with the stock 12ax7 in it. I've gigged it a couple times already, and the line out I had added worked well. I'll also run thru the Epi cab my buddy owns, and do a side-by-side with the Kalamazoo, and with the same camera so the audio is consistent. I really need to beg/borrow/barter a Zoom or comparable digital recorder to to some more true-to-life recordings.
