Jensen Electric Lightning in the Blues Junior

[Middleman]

Just went to the amp show here in LA today and won a Jensen 12" Electric Lightning. This evening I installed it in my Blues Junior which has the Billm mods and the original 12 inch.

In a word it sounds amazing. Very clean and clear low end, sparkling highs which are smoother than the original speaker and completely tames the midrange. It's a little over-rated for the amp so I can run it up to 10 and it doesn't flinch. Very rich sounding with my strat, warm but clear and defined. Not sterile either. Overwhelming powerful and clear is the best description. Almost reminds me of my old Musicman amp in its response.

Anyway, thought I would share. Matches my strat extremely well. I will add some more impressions after I try out the tele.

[JohnnyCrash]

Its supposed to be closer to a Vintage 30, with a slightly less present midrange hump.

Having used V30's for probably 15 years I ordered a Jensen Electric Lightning for my isolation cab. Its not as close to a V30 as I wanted, but it is definitely an awesome speaker. Its been in my Iso cab for months and will likely be there forever. Articulate highs (almost harsh at first, but mellowed after some break-in to a really nice treble), present but smoothed mids (I really like excessive mids though), with enough bass for my needs. If you like V30's but don't want as much "honk," the Jensen EL's are great.

[EdMax]

I have been loving that speaker ever since it arrived!

The Lightning is most likely the best rock & roll speaker Jensen has come up with in recent years.

I agree with Johnny on the Highs, but that is pretty subjective to the type of amp its used in. On tweed circuits, the clarity and shimmer/chime is a real bonus considring its a ceramic magnet speaker.
I think the mids are fairly strong, but pale somewhat with the huge bottom end.
Overall it gives my amp a fatness I had never gotten before with other Jensens. It seems to hold together better on the bottom end as well. Much less flub in my Deluxe and more usable range overall.

Excellent speaker, and the price is not bad either.

[Middleman]

Originally Posted by JohnnyCrash

Its supposed to be closer to a Vintage 30, with a slightly less present midrange hump.

Good to know because I had originally been thinking about the Vintage 30. I am going to hang with this one for awhile.

[Middleman]

Ok, ran my 72 Telecaster through the amp this morning. Between this speaker and the Billm mods, you can turn the bass to 0, run the mids up to 10, treble at 6, pre and master about 6 and to my ears, this sounds exactly like a twin reverb. Well maybe half a twin reverb because there is only 1x12 speaker. Pretty amazing. I should mention I have different cap values than the Billm mods. I have found that you actually get more low end by not using the bass control at all and running the mids up to 10. If you turn up the bass knob a lot of midrange build up occurs.

Pretty nice approach to a lightweight sounding twin. This can get really loud without breakup which is why it takes on a twin tone. If you go the other direction and try to overdrive the preamp, it sounds like a stock BJ on overdrive but a bit cleaner. Not sure this is all that useful and a better approach is an overdrive pedal. Overall a really nice approach to getting some mileage out of a BJr.

[Billm]

more bass with mids on 10, etc.

Did you do the TwinStack mod? Curious to know what values you're using in the stack. My experience is after you do the TwinStack, you get much better separation between the bass and mids controls.

Still, one of the quirks of the Fender stack is that it's flat when you have the bass and treble off and the mids all the way up. Then you can use a little bass and treble for "seasoning."

[Middleman]

Yes, did the twin stack mod. I don't remember the values but I remember I deviated from the norm. I would say the separation is there but I get a more rounded and deeper low end when the bass is rolled off and the mid is at 10. If I bring up the bass the amp gets very honky sounding because its passing more of the mid range as well. Suffice it to say, the best tone is when the mids are at 10 and the bass is rolled off. Not ruling out that I may have done something non-normal during the conversion which would attribute to the results.

[Billm]

I'd love to see a pic of your circuit board and the values if you ever take the back off one day. I'd like to run the values through Duncan's tone stack calculator to see what the interaction looks like.

[JohnnyCrash]

You might consider downloading the Duncan Tonestack Calculator.

As you turn up the virtual Mid control and turn down the Treble and Bass you can see how it makes for a completely even, or flat, frequency response (generally, an ugly sound). It also allows you to plug in cap/resistor values to see what the changes are.

TMB tonestacks work on an attenuation principle where every frequency range is attenuated and you're actually reducing attenution on certain frequencies by turning up the knob associated with it (cranking the treble knob, reduces its dampening or attenuation). Cranking the mids actually reduces any "boosts" (not really boosting, just reducing attenuation) the Treble or Bass knob offer.

A preamp setup, tonestack, coupling capacitors, tube brand/model, output transformer, and finally the speaker all have some frequencies more or less prominent... its a lot of ingredients to make for certain boosts/cuts in certain frequencies, but at least with the tonestack calculator and a few givens (knowing how the amp sounds as-is, the character of the speaker, etc) you can dial in the tonestack to taste.

[Middleman]

Originally Posted by Billm

I'd love to see a pic of your circuit board and the values if you ever take the back off one day. I'd like to run the values through Duncan's tone stack calculator to see what the interaction looks like.

Sure thing. I will pull off the back tonight.

Update: Ok, operator error here. Looking at the front of the amp (which sits up on the amp stand and tilted back) and having not even looked at the controls in awhile, I was assuming the knob to the right of treble was the midrange. The middle knob is actually the bass knob and the mid control is to the right of that. So we have, going from left to right treble, bass, mid and not treble, mid, bass. So I thought I was rolling off bass when I turned down what was actually the midrange. So ignore my setting above. I was actually rolling off the midrange and increasing the bass and not the opposite.

That said, I will get the values off the caps later tonight. Gonna grab a bite to eat.

[Middleman]

Took some pictures but they are not clear enough to provide any data. I wrote down the numbers and the values are 250pf for treble, .1uf for bass and .022uf for mid range. I noticed a lot of my favorite Fender amp schematics used the .1 in the bass position and so I swapped in that value. I really like the tone it provides.

Still can't believe the mid knob is not in between the treble and bass knobs. That is too weird. I ran this through the Duncan TSC 1.3 and it creates a very steep mid range cut which this amp really needs due to the small cabinet size. Anyway, I like the tone now with the mid at 0, bass at 10 and treble at 6. The fat switch is engaged and master and channel are at 6. Killer tone.

[TeleV]

Quote: I wrote down the numbers and the values are 250pf for treble, .1uf for bass and .022uf for mid range. I noticed a lot of my favorite Fender amp schematics used the .1 in the bass position and so I swapped in that value. I really like the tone it provides.

Billm's Tone Stack mods call for:

1. no change to treble cap leave at 250pf
2. change bass cap from .022uf to 0.1uf
3. change mid cap from .022uf to .015uf

So the only difference between yours and Billm's is the mid cap value and you're not even using that.

Billm's Tone Stack Mod: http://home.comcast.net./~machrone/bjr/bjtone.htm

[Billm]

Just changing the bass cap hardly constitutes the Billm mods. :)

Note that on the Duncan Tone Stack Calculator, the Fender stack is essentially the one from the Pro and Twin Reverb; it has the TwinStack jumper, To simulate the stack in the Blues Junior, without the jumper, use the Marshall stack. You'll have to change the pot and slope resistor values to match the Fender parts, though.

I like to reduce the mids cap to .015uF, which leaves more mids in the stack--and a lot more bass. But after the TwinStack mod, you can pull all of the mids out, giving you a bigger range of adjustment.

BTW, there are Orange Drops that actually fit, without all that awful lead bending and tucking under or hitting other components.

[Middleman]

Originally Posted by TeleV

So the only difference between yours and Billm's is the mid cap value and you're not even using that.

Billm's Tone Stack Mod: http://home.comcast.net./~machrone/bjr/bjtone.htm

TeleV: No, you need to re-read the thread. The only changed value is the bass cap which is .1. The mid and treble were not changed.


Billm - What you can't see here is the twin stack mod on the under side of the board so that is also in place. Ok, I won't use your name in vain calling it a Billm mod. Maybe I should say inspired by the Billm mod. I did spend time searching for for smaller caps but could not find them so I went with the current size. I did actually try your values by the way, but it was not the tone I was looking for.

[TeleV]

Originally Posted by Middleman

TeleV: No, you need to re-read the thread. The only changed value is the bass cap which is .1. The mid and treble were not changed.

I did re-read the thread and my statement still stands - the only difference between your current amp and a Billm Tone stack mod is the value of your mid cap which you did not change but Billm does.

-------Billm.....Yours
Bass___0.1____0.1
Treble_250____250
Mid____0.15___0.22

[Middleman]

Originally Posted by TeleV

I did re-read the thread and my statement still stands - the only difference between your current amp and a Billm Tone stack mod is the value of your mid cap which you did not change but Billm does.

-------Billm.....Yours
Bass___0.1____0.1
Treble_250____250
Mid____0.15___0.22

Ok, got you. You are comparing to Billm and I was just commenting on the values I changed. So yes, in the end the only change was to the bass value which was the same recommendation as Bills, mid was not changed.

[JohnnyCrash]

What's your slope resistor's value?

[Middleman]

Originally Posted by JohnnyCrash

What's your slope resistor's value?

100k