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Dirty-South Blues Harp forum: wail on! >
EUROTUBE 6V6 harp re-tube kit for BMRI anyone?
EUROTUBE 6V6 harp re-tube kit for BMRI anyone?
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bonedog569
694 posts
Nov 05, 2012
11:40 PM
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Anhyone try this? Any thoughts?
I am digging the amp muchly, - but need to put in at least one hearing protector for the volume - to make it 'sing' in my studio.
The JJ 66's can supposedly take the voltage - and I did install that bias pot.
Dangers? Downsides?
http://ssl.eurotubes.com/cart/index.php?page=view_products&category_id=7&sub_category_id=129
Fender 59RI For Harp With 6V6's
Price: $80.00
Description: If your 59RI is the LTD or later model with an adjustable bias then this kit can be used to lower the output for you harp players looking to get earlier power tube breakup. This kit includes a matched pair of the JJ 6V6's,a GZ34 rectifier, a standard ECC81 for V1, a standard ECC83S for V2 and an ECC832 for V3.
the ECC832 is a mismatched double triode. He's trying to emulate the imbalance of a paraphrase inverter i guess - or following the Mullet haired one's advice (Gerald Weber)
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tmf714
1332 posts
Nov 06, 2012
4:41 AM
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From the Telecaster forum-
Put a pair of 6V6's and a 5Y3GT in my 59 BMRI and...
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Holy schnikey! Now this is the tweed sound I always hear in my head!
I had been looking into other speakers for my 59 Bassman RI (an early 90's one that's been to hell and back) and was going to go with 4 smooth cone alnicos. Then I decided I'd do a mix of 2 smooth cone alnicos and 2 ribbed cone ceramics (since I already had one smooth cone and the 2 ribbed in the amp already). My goal was to lower the overall volume of the amp to get to the sweet spot a little better for that great tweed crunch and singing feedback.
Well, I got it!
I read about people putting 6V6's in their Bassmen, and how people say that the only 6V6's that are stout enough for the job are JJ 6V6's. I didn't see any mention of swapping the rectifier tube, though.
So I did what I almost always do-- I consult my good tele playing friend and fellow TDPRI'er, Bob Arbogast. I trust Bob implicitly with this sort of thing since he's built so many different tweed amps and really knows his stuff. He assured me that, aside from the 6V6's running a little cold (since the amp is currently biased for JJ 6L6GC's) and a slight impedance mismatch (6V6's are looking for 4 ohms, not the 2 ohms that the amp is currently wired for), I'd be safe to do the experiment.
I used an old set of used RCA 6V6's and a JAN Sylvania 5Y3GT. I've been playing for about a half hour and the amp has been on the whole time, not on standby. No glowing plates on the power tubes, no funny sounds, etc.
The whole feel of the amp has changed. With 6L6's and a 5AR4, it just sounds BIG and clean and deafeningly loud when it gets up to around 4 on the volume knob. Not a whole lot of breakup at that point, just really frickin' loud and powerful.
With the 6V6/5Y3GT setup, I feel like the amp's breathing more. I can safely get it up to 4 on both volumes (plugged into the Normal channel) and start getting that fat crunch and breakup. Up to 6-7 and I'm into singing feedback and a great ballsy rock sound. This is with my single bridge 'bucker equipped esquire with a Duncan 59N in it. No pedals necessary.
At volumes 4 and below, it feels much looser than with the 6L6's. I'm definitely hearing that 6V6 looseness. I think, for me, that's a key part of the tweed sound.
I still feel a bit like these tubes in this amp is a bit like sex with your sister-- sure, the parts fit and it feels good, but maybe it just ain't right. But this setup sounds waaaay more rock & roll than the 6L6 setup.
True, it's not quite as versatile-- the super big clean 6L6 setup allows for alot more headroom and a tighter, bigger clean sound that can be spiced up with pedals, but that's what I was experimenting to get away from. Looks like it worked!
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tmf714
1333 posts
Nov 06, 2012
4:45 AM
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The Fender forum-
The JJ 6V6s (and only the JJ 6V6s) sold by Eurotubes ( http://www.eurotubes.com/ ) are designed to handle a plate voltage of 450 VDC. They are sold in retube kits by Eurotubes for various amps including the 59 Bassman LTD:
"Fender 59RI Standard Retube with 6V6's
Price: $78.00
Description: If your 59RI is the LTD or later model with an adjustable bias then this kit can be used to lower the output. This kit includes a matched pair of the JJ 6V6's, a GZ34 rectifier tube and three ECC83S preamp tubes with one of them balanced for the phase inverter in V3. This will drop the power down to a little less than 30 watts to get you an earlier breakup and a great vintage tone!"
As noted, they can only be used with the 59 bassman reissues that incorporate an adjustable bias pot.
Although I have not heard this retube kit, I have one of Eurotubes retube kits for my BDRI and can vouch for its quality and sound (both great).
Regarding the safety/reliability of the Eurotube 6V6 kit, considering the liability issues if Eurotubes were wrong, I have no doubt that what they are selling is a very viable product and I would have no hesitation in buying one if I were in the market to do so.
All that said, the difference in loudness between 30 watts and 40 watts with the same speakers is negligible. The amp may break up earlier with the 6V6s versus the stock 6L6GCs, but it will still be one loud amp.
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5F6H
1408 posts
Nov 06, 2012
6:21 AM
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"The JJ 6V6s (and only the JJ 6V6s) sold by Eurotubes ( http://www.eurotubes.com/ ) are designed to handle a plate voltage of 450 VDC."
The JJs actually handle at least 500vdc (at appropriate bias current) on the plates. EH & Shuguang, TAD all sell current production 6V6 tubes that handle over 450vdc. EH are rated to ~470vdc, but can't handle as much current as the JJ. It makes sense for curent manufacturers to make high voltage handling 6V6s, because unless you bias all old tolex BF/SF Princetons & Deluxes very hot, they run in the mid 400's. I have seen 470vdc on PRRIs with a GZ34 & EH power tubes running 23mA (factory schem quotes 440vdc).
RI 5F6As can run up to 525vdc, so unless you know for sure what your plate voltage is, it is best to stick to JJ6V6 if trying this. I'd aim to keep them between 17 & 20mA in a bassman (the bias pot is very useful here, but the fixed resistor circuits can be adjusted too, just like when subbing different brands of 6L6. On some amps the JJ6V6 will drop straight in - CHECK BIAS current, don't assume or guess).
NOS 6V6s can usually handle plenty of current compared to many current production tubes, but typically aren't rated for as high voltage on the screens & should be kept to 425vdc or less on the plate.
"All that said, the difference in loudness between 30 watts and 40 watts with the same speakers is negligible. The amp may break up earlier with the 6V6s versus the stock 6L6GCs, but it will still be one loud amp." This is very true...you may well notice a difference in tone & compression, but the amp will only be a tiny bit quieter (if any) unless you change rectifiers for less B+ voltage.
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tmf714
1334 posts
Nov 06, 2012
7:04 AM
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From Eurotubes-
JJ Electronic 6V6S
Factory description: Gold plated control grid for improved fidelity. Special plate alloy improves performance over any 6V6. This tube has the ability to handle 450 plate volts in triode mode and 500 plate volts in pentode mode
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5F6H
1409 posts
Nov 06, 2012
7:18 AM
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5F6A Bassmans come stock wired as "pentodes" (it's really a tetrode with 6L6/6V6, as there is no surpressor grid, like there is in a EL34 pentode).
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arnenym
87 posts
Nov 06, 2012
10:20 AM
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How about use a 5Y3 as a voltage dropper as tmf714 write in his post. It is something i heard about before...
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5F6H
1410 posts
Nov 06, 2012
10:43 AM
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Sure, you can try that with modern production 6V6s...depending on the specific amp in question, it may, or may not give you enough of a drop to get low enough for NOS 6V6s.
Running 5881/6L6 with a NOS 5Y3 in fixed bias is possible, as long as you appreciate the rectifier will be stressed and will die from time to time, taking the fuse(s) with it. 5R4 has a big drop, handles much more current than NOS 5Y3, some have given me arcing issues in a stock wired 5F6A RI...but it might be worth a go (try the "WGB" ruggedised mil. spec version)?
If you are trying to get a big voltage drop it may be more practical to use a copper cap WY3 or WR4 (they often drop a little more than a glass version), but these are not indestructible either & not everyone likes the tone.
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Rick Davis
892 posts
Nov 06, 2012
12:23 PM
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This is something Al Chesis does frequently: Swap in 6V6 power tubes in his Bandmaster clone. Sounds killer.
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-Rick Davis
The Blues Harp Amps Blog
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1847
330 posts
Nov 06, 2012
2:15 PM
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is this a similar mod to the
ken fischer train wreck?
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5F6H
1411 posts
Nov 06, 2012
2:44 PM
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Hi JD, yeeess-ish! ;-) Typically 6V6 are operated into a ~8K transformer winding (primary impedance). A tweed bassman with a 2ohms speaker load is 4K primary Z, half what the 6V6s normally see. But tubes will operate into a range of loads (as long as you know these loads are safe)...e.g. if you add an 8ohm ext speaker to a Deluxe Reverb (4ohms total speaker load) the 6V6s see around 3.5K and they take that...they might wear fractionally faster. Some old Mascos run their 6V6s into a little over 4K...so, yes, stock 2ohm speaker load/4K primary load is on the low side of normal for 6V6. If you were at all worried you could disconnect one (or two) speakers on the bassman, with 6V6 installed and that would show the tubes 5.3K (8K with 2 speakers @ 4ohms)...plenty safe - this is one reason I like the "in-between" impedances you can get with 3 speakers, as they can sit in the useful range for both 6V6 & 6L6...assuming voltages & bias are good.
@1847 - There was a Trainwreck (Express) that could sub EL34 for 6V6? There was a lot more to Trainwrecks than this though...you can sub 6L6/5881/EL34 for 6V6 in any amp that runs the voltages low enough, has an acceptable output transformer primary impedance & suitable sweep/setting on the bias circuit (I have a few amps that can run 6V6/6L6/5881/EL34/6550/KT90). Swapping 6V6 for larger tubes is potentialy a bigger problem as the bigger tubes draw more current on the plates & the heater circuits & can burn out borderline transformers.
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Last Edited by on Nov 06, 2012 2:49 PM
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JD Hoskins
16 posts
Nov 06, 2012
3:05 PM
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Thanks Mark, I was actually thinking of putting my spare bassman in a two speaker cabinet maybe. I run Phillips 5881's in my Deluxe Reverb (guitar) and have for years with one 8ohm 12" speaker, no problems with the mismatch and it sounds amazing and is so much easier to pack around than a Super Reverb.
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