5E3 build complete - low speaker buzz

[scstill]

Looking for some advice. My 5e3 deluxe build aka "Goldeluxe 03" is completed. Point wiring. My third build from scratch. Sounds really good.
I've mounted this in a 40's skate box with cutouts for the speakers and the custom chassis (all from scratch)
Unfortunately the speakers I've selected have buzz on certain low notes. Worse with humbuckers. The speakers are a pair of 50s ceramic jensen 6x9 harvested from old organ. Thinking that these don't have the low end that the 5e3 demands. I have tried several same type of speaker and they all have buzz (some worse). There is no buzz when I run it into my Egnator 12 cabinet. Is there anything that I might do with the circuit or the 6x9 speakers short of designing a new cabinet for a modern 12"?
Thanks

20200429_213422.jpeg

[sluckey]

Weber sells some 6x9s that may help...

https://www.tedweber.com/6x9a

[Dr Tony Balls]

Have you tried plugging the amp into another speaker to first verify that the speakers are definitely the problem?

[ChopSauce]

Great build from scratch! Did you folded the chassis yourself?

PS You're lucky if you live closer to Weber than I do ...

[scstill]

The buzz isnt on every note only on a few low ones, and surprizingly not even the lowest
I should have mentioned that I isolated cabinet buzz (has some in the hinges and latches and handle)
The speakers are out of the cabinet on a carpeted floor, buzz becomes less if I lightly touch the cones
seems that one of the speakers is worse than the other
I have also tried a couple of other same model speakers (I have a few) and they buzz to different degrees
I also ran the amp into a Egnator 12 and even eminence 6" - no buzz
Bummer is that The cabinet is tight and fully custom to 6x9s and the chassis. I did not fold the chassis just layout and cutout

[scstill]

Update....

I tried an equalizer in front of the amp and cut the lows. The buzz was gone,\
So, I tried to reduce the preamp coupling capacitor (on the bright channel) from .1 to .02 thinking too much bass. 
But it still buzzed the speaker. Its ok at low volumes. Any thoughts about cutting the bass?

The other thing I did was with the speakers out of the cabinet I laid them on the carpeted floor and the buzz was gone.
So I thought the gasket might be ineffective. I added some felt washers at each corner to see if that might help.
But the buzz is still present when not pointed at floor.

Maybe I'll try new gaskets and then look at the weber 6x9s
But its sad that the Jensens aren't working

[sluckey]

There are two 25µF caps, one on V1 cathode and the other on V2 cathode. Replace these with 2.2µF or 4.7µF caps. Then replace the two .1µF coupling caps between the PI and power amp grids with .022µF or .047µF caps. All this will reduce the bass in the amp and may hide the effects of your buzzy speakers.

[scstill]

There are two 25µF caps, one on V1 cathode and the other on V2 cathode. Replace these with 2.2µF or 4.7µF caps. Then replace the two .1µF coupling caps between the PI and power amp grids with .022µF or .047µF caps. All this will reduce the bass in the amp and may hide the effects of your buzzy speakers.

Do you think the coupling cap between preamp gain 2 and PI should also be reduced? Value?

As well as the coupling caps between preamp gain 1 and gain 2?

Alot of surgery. What will this ultimately do to the tone of the circuit?

[scstill]

Is there any thought about replacing the gaskets on the c69r jensens?
What do you think the low response is of these speakers?
What do you think the power handling is?

[sluckey]

Do you think the coupling cap between preamp gain 2 and PI should also be reduced? Value?

No. Leave it at .02

As well as the coupling caps between preamp gain 1 and gain 2?

Change to .02 or .047.

Alot of surgery. What will this ultimately do to the tone of the circuit?

This will minimize the boomy bass of the 5E3 circuit. Maybe the decreased bass will allow you to use those inadaquate speakers.

A lot of people will do some or all of the mods I described even when using a proper 12" speaker with the 5E3. You have a novel idea for your project. I like doing stuff like this too. Heck, I even have an amp in a '60s toaster oven. But you have to accept the limitations of your project. Those organ speakers can't handle the boom that the 5E3 will give it. A pair of the Webers will probably give you a nice 5E3 sound at parlor volume and allow you to keep your cool cab, but don't expect those to play in a club unless mic'ed.

[scstill]

This will minimize the boomy bass of the 5E3 circuit. Maybe the decreased bass will allow you to use those inadaquate speakers.

I'm thinking the Jensens are inadequate as well. But when you look at the circuit that they came out of (link below), they were each driven by 7189 in push pull which delivers 16w (like the 5E3) and I cannot see anything that would cut the low end from the 6x9 channels.

http://www.captain-foldback.com/Leslie_ ... cs/102.gif

[didit]

[...]
But when you look at the circuit that they came out of (link below), they were each driven by 7189 in push pull which delivers 16w (like the 5E3) and I cannot see anything that would cut the low end from the 6x9 channels.

Hmm .. 0.02uF PI->power-tube coupling capacitors and 10uF cathode resistor bypass capacitor on a lo-gain stage? Seems like that amp designer might have getting sage advice from sluckey.

Best .. Ian

[ChopSauce]

I'm thinking the Jensens are inadequate as well. But when you look at the circuit that they came out of (link below), they were each driven by 7189 in push pull which delivers 16w (like the 5E3) and I cannot see anything that would cut the low end from the 6x9 channels.

Might that have damaged them already?

[scstill]

Do you think the coupling cap between preamp gain 2 and PI should also be reduced? Value?

No. Leave it at .02

As well as the coupling caps between preamp gain 1 and gain 2?

Change to .02 or .047.

Alot of surgery. What will this ultimately do to the tone of the circuit?

This will minimize the boomy bass of the 5E3 circuit. Maybe the decreased bass will allow you to use those inadaquate speakers.

A lot of people will do some or all of the mods I described even when using a proper 12" speaker with the 5E3. You have a novel idea for your project. I like doing stuff like this too. Heck, I even have an amp in a '60s toaster oven. But you have to accept the limitations of your project. Those organ speakers can't handle the boom that the 5E3 will give it. A pair of the Webers will probably give you a nice 5E3 sound at parlor volume and allow you to keep your cool cab, but don't expect those to play in a club unless mic'ed.

As a follow-up on the "Goldeluxe 03" custom build, I replaced the 6 caps as suggested and went thru the lot of 6x9 speakers to find the best of the best.
It sounds good now, but still can overdrive the speakers. The 5E3 is a beast. Planning on trying the webers.
Not sure I will keep the modified circuit or go back to original.
In any event I learned alot from this post and appreciate everyones suggestions.
Thank you all...