Fender "Evil Twin" Tube Question

[Guitar55]

There is also a 120W (or 130 Watt) Silverface Twin which I think was from the 70's. This thing packs a mighty punch!

[Darklava]

Originally posted by Caevan O'Shite:

Yeah, those amps could benefit from a better cabinet. LPCustom/Bruce? Anyone? Anyone?

 

There's a good chance that the 'verb is noisy on DL's because of it's having been chopped-n-channeled from a 2x12-combo format into being a head; this places the reverb-pan much, much closer to all those tubes 'n' caps 'n' transformers...

 

Searching for other info online, I ran across references to other people having to replace those large resistors in the power-supply like I had to; must be a fairly common problem with these...

I certainly hope thats not the case,i think i'm

going to take Bri up on that offer seeing as this

guy has just worked on his amp.

[Caevan O’Shite]

Best of luck with that, DL, and definitely keep us posted!

 

At least the flimsy cab-work isn't an issue with yours, huh?

[blazinslow2.8]

I suppose this question would be to Caevan O'Shite because he seems to really know his amps.

 

I recently bought a used Fender "red knob" The Twin. I got it for $200 because it did not work. The repairman replaced a blown resistor and some tubes and now it works great. I really like it, but I have one concern:

 

Whenever the volume is set at anything above 2 or 3 (maybe a little higher in 100 watt mode) the bass range causes an unpleasant distortion. The distortion is mostly evident when playing dissonant combinations of low notes. For instance, play a D chord in the open position and add the low F# on the sixth string and the chord becomes lost in low frequency noise.

 

The above scenario describes the sound of the clean channel when the tone controls are all in the middle, which tends to be my comfort zone on most amps. If I turn the bass knob all the way down the tone becomes clean and I can play at very high volumes with no undesired noise.

 

I just wonder if this is at all normal for this amp, or perhaps there is something else wrong. Could this be a bias or tube issue? I looked at the tubes, which included two 12AX7's and four 6L6's. The bias and balance seem to be correct.

 

I was looking for super-clean, full, jazz tone and a decent dirty sound and I thought this was the amp for me. Now I'm not sure. I'm considering selling this amp and getting a DeVille, which I have used in the past with great results, but I'd rather get comfortable with what I have. Please tell me if I should keep trying to fix it or just learn to live with it.

[Funk Jazz]

theres definitely something wrong with your amp, blazinslow2.8. red knob twins usually have some of the tightest low end you'll here because of the huge transformer.

 

you should have it checked out again for sure.

[Caevan O’Shite]

Burnt resistors- particularly specific heavy-duty ones in the power-supply and/or output section, IIRC- are aparently a common problem with these "red-knob" amps (I had to swap one out in the one I used to have), and tubes will always eventually wear-out.

 

But, this amp should be able to handle quite a bit of low-end, including a D/F# like that. Is what you describe as, "low frequency noise", a woofy/farting/"bassing-out" speaker sort of sound, or is it an electronic-sounding kind of distorted cluster of low frequencies? The reason I ask is that it could

 

Hmn, is that with any of the "pull"-functions engaged, particularly the bass-boost?

 

I doubt that the tubes or bias have anything to do with this. Although it could be a problem with an overly microphonic preamp-tube; and I had to remove the tube-shields on mine, but the problem there was high-frequency jingly noises. It's hard to diagnose without seeing and hearing it first-hand in real-life, too!

 

Uhmn, I hate to say it, but it could also possibly be a bad solder-joint connection vibrating sympathetically within the amp.

 

Can you connect the amp to different speakers, instead of the internal speakers? (Using the main speaker-output jack, unplugging the on-board ones and connecting the substitute-cab to that jack, setting the nearby impedance-selector switch appropriately.)

 

If the problem disappears when connected to an external cab and speakers, then it's either a matter of sympatic vibration at some point, or the speakers themselves needing replacement.

 

I think that if you can't track this down yourself in fairly short order, you might want to at least discuss the matter with the repair-tech who recently serviced this amp for you; he's already been inside it and should be able to suss it out pretty quickly once he can experience the problem first-hand (preferreably with the same guitar and cable that you used when it's happened to you.) I also used to own a Fender Hot Rod DeVille 2x12, and between the two amps- both purchased new- I feel that the "red-knob" The Twin would be the better of the two for a "super-clean, full, jazz tone".

[blazinslow2.8]

Thank you both for your responses. Exactly the advice I was looking for. I'll talk with the technician about it.

[blazinslow2.8]

Thank you both for your responses. Exactly the advice I was looking for. I'll talk with the technician about it.

[BriBaby]

Great advice from the king.........mine has no problems with any notes like that, so if it was me, I would try what Caevan suggested. If none of that was the trouble, then by all means I would take it back to your amp repairman.

[BriBaby]

p.s. If, for some reason it doesn't work out for you, I would be willing to take it off your hands for a back up to mine.

[Darklava]

Sorry i just bought it...

[BriBaby]

Originally posted by Darklava:

Sorry i just bought it...

Cool, I know where to borrow one now if my rig goes down

[Caevan O’Shite]

I'm gonna have to get another "red-knob" The Twin someday; and I'd also like to get an early '80s "second blackface" Pro Reverb, they sound so big 'n bold 'n' wrangly for clean reverby bits. But I'd wrather have a Tone King first...

 

Hey, Darklava, how'd you like my recommended settings for a high-gain heavy overdrive/distortion sound? Or, didn't you like it?

 

 

FWIW, I used the above settings with an active EMG 85 humbucker at the bridge, and SA single-coil sized at the neck and middle; mostly the bridge humbucker by itself.

 

Sometimes with a T.C. Electronics Chorus/Flanger and some echo/delay in the effects-loop (with the fx-loop's level selector-switch set appropriately, NOT using the in-between 'boost' trick).

 

Speaking of that trick, it also makes the clean/rhythm channel mo' vintage-y pre-C.B.S. "blackface" sounding...

 

- AND -

 

If you don't already have one, get a good Digital Multi Meter and follow the directions on the back-panel to a "T", to use the test-points and trim-pots to set the bias and balance of the output-tubes; it's a great feature!

[Darklava]

Sounds great! i'll tell ya this is a flame thrower.

One question though have you ever heard about

pulling the two middle power tubes to bring

it down to 15/65 watts?and if so do you have to rebias the amp?

[Caevan O’Shite]

Yhup, I used to run mine with a duet of N.O.S. Phillips 6L6 STR stylees, but mostly just 'cause I was too cheap to spring for a new matched quartet of Groove Tubes.

 

It wouldn't be a bad idea to check and readjust the bias and balance with a good Digital Multi-Meter via the handy test-points and trim-pots there on the back.

 

Be sure to set the impedance-selector switch to half of whatever you'd normally have it at with four tubes; "half the tubes, half the impedance".

 

I'd also suggest that you get a separate duet of matched 6L6s and another "MPI" phase-inverter for this; if you just pull two of the four, they'll wear unevenly and become very UN-matched. And even if you never intend to use all four of the matched quartet again, this way you'll have three sets of matched-duets and two MPIs all on call.

[blazinslow2.8]

Ok, I hope you guys don't mind me reviving this old thread again, but I talked to the repairman who worked on my Twin, and he checked it out a bit.

 

Upon reasessment, I would define the problem as very dirty tone coming through the clean channel. The problem is just more evident when playing in the lower range. The amp is breaking up extremely early.

 

The repair guy replaced the four output tubes, as well as several of the driver tubes and replaced the 12at7 with a 12ax7. The amp still sounds the same.

 

Next he checked the wattage of each of the four brand new output tubes, which was about eleven watts tops each with the power switch on "HI." At this setting, the maximum wattage is supposedly 100, but apparently I'm getting about forty-four. Herein lies the problem.

 

He says he MIGHT be able to fix this, but I will have to pay a bench charge of seventy bucks just for him to look at it.

 

Here is my question, is this amp worth all the grief? Should I just sell it, and if so, how much should I expect? What is a fair price for a new Twin or DeVille? I'm begining to think that dysfunction is just the unavoidable nature of tube amplifiers.

[janalon]

Originally posted by CaevanO'Shite:

I'd imagine that you could elect to use a duet of the Yellow Jackets (instead of all four of the sockets in your amp) if you wanted, and I also think it would be perfectly fine to use your amp's low-power switch to further reduce overall output to introduce the spongiest, saggiest vintage-y feel possible from that 85# 2x12 monster.

What does "sag" mean. I've heard it thrown around left and right in guitar and effects forums, ,but have never bothered to ask. In all this time I never could quite grasp the definition through context clues - can you explain?

 

Thanks

[Linguine]

Killin' time on the computer and looked up my old red-knobbed twin (Circa 1987. Got a real hoot at reading the posts. Every single one of the gliches that are mentioned in the posts happened to mine. I too broke the back panel. I screwed in two big metal bars across the break and it it broke in another place. Fixed it again and it broke in ANOTHER place.

The solder joints have gone bad. So often did this occur (one time at an important gig-Had to borrow someone rack system-UGHH!) That I ended up doing the solder joints myself instead of another trip to the shop.

The red knobs stick out precariously past the face of the amp and they break easily. Twice even the stem of the pot. broke. I was smart and bought a few extras back in the eighties.

The jacks are made of plastic and I have been told that they cannot be upgraded to metal because they contain switching circuits in them.

Iv'e stripped a couple of them

This being said, I too have a love hate relationship with the amp. The amp provides both joy and heartache...and backache. It has sounded remarkable at times and it's ability to provide the goods surpasses many amps around, but it has broken down way too much. (I am not hard on amps either. My 62 Concert has NEVER broken down and it gigged a helleva lot more than the Twin)I havn't used the amp in years but can't seem to get rid of it because, well, because strangly through all of those repairs, I feel connected to the darn thing. It's really a good sounding amp.Hey I just saw Warren Haynes play through one.

I believe the amp has the spirit of a woman.

"Not tonight Dear, My solder joints are cramping and my back(plate) is sore" or "Do you really think you're going to put that jack in there and I'm just going to work? I don't think so!"

I enjoyed the posts

[Caevan O’Shite]

Originally posted by blazinslow2.8:

"Upon reasessment, I would define the problem as very dirty tone coming through the clean channel. The problem is just more evident when playing in the lower range. The amp is breaking up extremely early."

 

The repair guy replaced the four output tubes, as well as several of the driver tubes and replaced the 12at7 with a 12ax7. The amp still sounds the same.

 

Next he checked the wattage of each of the four brand new output tubes, which was about eleven watts tops each with the power switch on "HI." At this setting, the maximum wattage is supposedly 100, but apparently I'm getting about forty-four. Herein lies the problem.

 

He says he MIGHT be able to fix this, but I will have to pay a bench charge of seventy bucks just for him to look at it.

 

Here is my question, is this amp worth all the grief?

Well, compared to the price of a lot of gear-type things people spend money on, $70 doesn't look so bad.

 

I'd run this by Myles (Myles rose, see the "Feel free to ask Myles"-thread above this one), spare no details, but be concise and clear and to the point, written in brief.

 

Uhmn, just a thought- there is a circuit in there that allows both the clean and dirty channels to be on simultaneously, depending on which input is used... perhaps this is related?

 

Originally posted by blazinslow2.8:

I'm begining to think that dysfunction is just the unavoidable nature of tube amplifiers.

Sometimes, I feel the same way...

 

Originally posted by janalon:

What does "sag" mean. I've heard it thrown around left and right in guitar and effects forums, ,but have never bothered to ask. In all this time I never could quite grasp the definition through context clues - can you explain?

 

Thanks

When an amp is pushed hard, cranked-up to the point of overdrive, and a demand is placed upon the power-supply that begins to exceed its realistic capabilities, a squishy, saggy, lagging, compressed response results, particularly affecting the picking-attack of notes hit hard. The amp has trouble keeping up, and a softened, rounded feel and sound reminiscent of smaller vintage amps turned way up. This is often described as "sag".

 

Originally posted by Linguine:

Killin' time on the computer and looked up my old red-knobbed twin (Circa 1987. Got a real hoot at reading the posts. Every single one of the gliches that are mentioned in the posts happened to mine. I too broke the back panel. I screwed in two big metal bars across the break and it it broke in another place. Fixed it again and it broke in ANOTHER place.

The solder joints have gone bad. So often did this occur (one time at an important gig-Had to borrow someone rack system-UGHH!) That I ended up doing the solder joints myself instead of another trip to the shop.

The red knobs stick out precariously past the face of the amp and they break easily. Twice even the stem of the pot. broke. I was smart and bought a few extras back in the eighties.

The jacks are made of plastic and I have been told that they cannot be upgraded to metal because they contain switching circuits in them.

Iv'e stripped a couple of them

This being said, I too have a love hate relationship with the amp. The amp provides both joy and heartache...and backache. It has sounded remarkable at times and it's ability to provide the goods surpasses many amps around, but it has broken down way too much. (I am not hard on amps either. My 62 Concert has NEVER broken down and it gigged a helleva lot more than the Twin)I havn't used the amp in years but can't seem to get rid of it because, well, because strangly through all of those repairs, I feel connected to the darn thing. It's really a good sounding amp.Hey I just saw Warren Haynes play through one.

I believe the amp has the spirit of a woman.

"Not tonight Dear, My solder joints are cramping and my back(plate) is sore" or "Do you really think you're going to put that jack in there and I'm just going to work? I don't think so!"

I enjoyed the posts

Hah! Yes! I had to do some re-soldering and touch-up in mine back in the day, even cobbing together a sort of a "jumper" to compensate for a bad PCB-trace and a waaay short lead on a small cap. And one of my pots suffered a sheared-off shaft, as well. (If I already stated these things before in this thread, I apologize for the redundencey here... )

[Dr. Ellwood]

Sag is also applied sometimes to describe the medium or low condition of dry batteries. There are certain effects that display a certain "special" set of characteristics that are seen as desirable to tone. This "sag" condition on some power supplies used to eliminate batteries in floor effects is sometimes duplicated to get this low power supply phenomenon.

[Caevan O’Shite]

Originally posted by ellwood:

Sag is also applied sometimes to describe the medium or low condition of dry batteries. There are certain effects that display a certain "special" set of characteristics that are seen as desirable to tone. This "sag" condition on some power supplies used to eliminate batteries in floor effects is sometimes duplicated to get this low power supply phenomenon.

Oh, yeah; I used to have a few pedals- old, "vintage" ones- that I liked the sound and feel of with old-style carbon batteries that were a bit tired. Conversely, the ic-stylee version of the EH Big Muff Pi pedal that I used to have sounded its best with as robust of a power-supply or alkaline batteries as I could give it; I often actually ran it with two 9v alkalines wired in parallel for this reason, so as to eliminate sag and get a bold, powerful response from it.

[jimash]

N.O.S. Sylvania "STR's. Also sold as Mesa 6L6 STR.

4 could set you back $300 easy. (if you can find 'em)

But they are the stuff for Fender high power amps like that badass Evil TWin.

[Toby_Gray]

Greetings,

 

'just found this forum after becoming a new owner of a '92 Red Knob. After going through it and repairing a broken pot, cracked back plate, adding tilt legs, etc., it's all looking and sounding very good except for a reverb reedback that comes on if the reverb knob is turned much past 9:00. After turning the reverb knob to "0" it goes away and is hardly noticable if the reverb isn't turned up too far. Changing the setting on the "loop" switch settings can increase the volume of the feedback but not eliminate it.

Any experiences or thoughts on what is going on?

 

TIA!

Toby

[Toby_Gray]

Stock Speaker impedance set up?

 

The 2 12" 8 ohm speakers in my red knob have been wired in series to be 16 ohms. Is this standard?

 

Thanks,

Toby

[Clive Hugh]

I know this is way out of date but I just found this forum, I have two of these, one is The Twin in combo form and the other a Dual Showman SR (spring reverb?), I play the Showman through an open backed cab. I made with 2x12 Eminence Red White and Blues Patriots. Of the two I prefer those speakers. As far as reliability goes I have replaced my reverb tank twice on The Twin, the Showman is in showroom condition, It had never been out of the previous owners home studio except when in the shop and it was used by and signed by Vinnie Moore. The Twin is currently playing up with crackles and no reverb again, but having said that it plays out in one of the harshest climates on the planet and has never let me down on a gig. I am driving to our state capital about 1200 miles and that is about the only bugbear there is to me, I have to go so far to get it repaired, but seeing as my daughter is getting married there it is a good chance to get it fixed at the same time. If I found another one in good nick I would be tempted to buy it but maybe not brave enough. I love them, I traded a Vox AC30 in on The Twin and have never regretted it.

[Clive Hugh]

Toby,

This is standard for these amps, both mine are 16 ohms and speakers in series.

Clive

[PhilDSP]

Nice information and stories gentlemen!

 

About 1990 I played one for the first time and immediately thought "Wow! this thing is a monster. I've gotta have one". I bought a used one in great condition about 8 years ago but never really took the time to play it much.

 

I just ordered an extremely expensive Mesa and was thinking maybe I'll sell the Fender. But I played it, really played, it last night and thought "Yeah, this is a nice amp" even though it doesn't come near to the tonal clarity you get from a Mesa. I has a coarser nature but a really fine bass extension even at high gain settings. I had always considered it an "evil twin" because of the extremely aggresive gain you can wrangle out of it.

 

Maybe replacing the tubes and recalibrating might bring in a substantial amount of tonal clarity and better articulation?

 

I discovered last night too, that using the channels in parallel REALLY gives you a fine sound - neither clean nor raunchy but the best of both worlds. That's the incredible 70's Steve Howe sound that has eluded me all this time. It was stacked Dual Showmans that he used in the early 70's I believe.

 

Now I have to figure out a way of parallelizing the channels on the Mesa...

 

What's the situation with Showmans? Could you overdrive them at all? Is the "red knob" Showman a re-issue in the same vein as "The Twin"? With parallel channel mixing and a decent amount of gain?

 

Philip

[Clive Hugh]

It would seem that the red knob "Showman" and "The Twin" are the same amp, jut put into different boxes, one in a combo and the other a head. Love 'em both.