Crackle sound from the 8″ Jensen

[Handley]

So, here’s the issue.
My two stroke build seems to be working fine except for one issue. At overdrive volume settings 5 and up) I get some nice thick chords but when I really dig into it the overdrive changes from warm to crackle. The crackle isn’t exactly harsh or non-musical but just seems like there is not a smooth transition from tube break-up to speaker break up or something. It is a very abrupt change and especially noticeable as the chord sustains and the guitar output drops off. It is more apparent in the Jensen 8″ both by itself and when combined with the 10.

I’ve tried different tubes (got worse with a 6k6GT) to no avail. No lose wires or shorting issues.

any suggestions or experience with something like this?

Is this speaker distortion as opposed to tube overdrive?

Is this a speaker break-in issue that will go away or should I get my hands on a
different speaker?

[Robin]

Sounds like a weak connection somewhere, check the solder joints, tube sockets, grounds.
It’s probably not the speaker. I know you triple checked everything already (we all do) and that all that all the solder joints are perfect (we all do that too), but 9 times out of 10….. Maybe more like 9.9 times out of 10, it’s going to be weak joint, marginal ground, tube socket or something like that. Of course, it could be a lot of things…. bad resister, pot, bad speaker, bad tube. Did you try the chop stick test to see if you an make it happen?

[Robin]

Probably not the speaker, Sounds like a weak connection, check solder joint, tube socket , grounds, etc. It could be a lot of things: bad resistor, bad pot, bad tube….. Did you use a chop stick to see if you could get it to do it after the amp has been on a while?

[Handley]

I know what you are saying about checking and rechecking the wiring but it isn’t that type of crackling sound. It’s not a short, soldering joint, or other type of electrical crackling and it only happens with the 8 inch rather than the 10 and only happens when a guitar is being played through it.

I usually play right at the point of clean/overdrive. I think some people might describe the crackling as just a jump to higher gain or from overdrive to distortion. It just seems very abrupt and I’d like to figure out a way to smooth out the abruptness of it.

[Robin]

Does it happen the same way with the boost switch in every position?
You checked that the tubes are good (replace with known good ones)
and that the sockets are ok? We had to re-tension a brand new octal socket on a TAN kit recently, but it was an easy fix and works fine now.
If it only happens with the 8, maybe it is the speaker, if it’s new, you can send it back to Jensen (5 year warranty), they are really good about that.

[Paul]

It’s tough in words to describe sound, but I can’t help but wonder if the “crackle” you are talking about is a speaker that is not screwed in right (either too tight or too loose) and is vibrating at higher volumes.

since it’s coming from just one speaker, just double check that.

if you don’t hear it with only the 10″ and you can’t fix it by playing with the 8″ speaker screws, then it’s probably the speaker.

I’ve gotten funny sounds out of my two stroke from both these problems on different occasions (and only at higher volumes) and fixed one by simply tightening one screw and the other by having weber replace a speaker under warranty.

[Handley]

Changed out the Jensen C8R for a Weber Alnico 8S and WOW, what a difference. I liked the amp before but was having trouble getting it dialed in for my needs. It always sounded too harsh with my Gretsch so I would use my G&L ASAT (humbucker in the neck). Also, it never really captured the “tweedy” tone I was looking for. Within a few minutes of trying out the new speaker I found myself detuning my Gretsch and playing the intro to “Twice as Hard.”

I’m a worship pastor and predominantly play in churches so I need the amp to overdrive at low(er) volume with a dark/smooth sort of sound. The tone was good before the swap and would have worked well for the club/bar type stuff but just didn’t sit in the mix right for my setting. The speaker swap definitely did the trick and got rid of the crackle.

Not knocking the Jensen speakers or those that prefer them. It just didn’t fit the bill for me.

[Don Frantz]

Hi Handley:

I think I might try that Weber Alnico 8S too. My Two Stroke sounds great as is, but I like the smooth dark early break-up you are describing.

Don

[Handley]

I couldn’t be happier with the tone I’m getting from it now. The Weber is smoother and darker than the Jensen and fits my needs well.

[Andy]

Did you happen to try Weber’s aging technique on the Jensen? I may have to try to compare the Weber 8S with an “aged” Jensen.

It’s interesting that the Weber is darker. My initial guess would be brighter because of the Alnico vs Ceramic. Just goes to show that there is much more to voicing than just magnet.

[Handley]

I did try the acetone aging technique. I don’t have a variac so after the acetone I connected them back up and ran some r&b music through it for an hour or so. It seemed to have more impact on the 10″ than on the 8″. I’m ok with the Jensen 10″ now but figured why just be “ok”? I ordered an Eminence Legend 1028K to try out, about $80 shipped from Amazon so not a huge investment.

[Andy]

Cool. I have been running the Weber 10F150 in place of the 10″. Thats a great option too.

[Handley]

Handley wrote:

$80 shipped from Amazon

Scratch that…
Amazon doesn’t have their models correct. If you order the Legend you will get a Lil’ Buddy instead. At least until they fix the issue.

[Robin]

The Lil Buddy might be the better choice anyway, it’s a great speaker.
I was thinking the same as Andy about breaking in the Jensen. Using Ted Weber’s break-in process (with a Variac) you can hear the speaker blossom in just a few minutes. Especially with some Jensens.

[Author]

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