Taming The Treble

[romberg]

Weber makes many hemp cone drivers.

Thanks. I have looked at the Weber speakers. They have a nice selection. I have an Eminence Cannibis Rex in my Blues Deluxe Reissue and like it a lot. Its kind of a middy speaker and may not work well in a closed back cab.

Arguably, speakers make more of a difference in "tone" than alot of the voodoo, black magic mojo in the amp. Or, at least as big a contribution as the amp. They are after all the part of the instrument that converts the energy from electrical to mechanical pressure waves a person can hear.

Speakers like tone stack settings, can be different due to personal taste. My favorite is the weber 1265. They are a celestion 12-65 clone that weber started doing before the celestion came out. And I'm just guessing that they cost a whole lot less.

Mike

[bluesky636]

Unfortunately, I don't have the $450 needed (plus shipping) to fill my 4x12 right now. We are having the interior of our house painted next week and that is costing over $3K (I hate painting. ). That's why I am looking for cheaper solutions that could be easily reversed if needed when I can upgrade the speakers.

[romberg]

Convince you wife that walls covered in speakers is better than paint!

Mike

[bluesky636]

That's not gonna happen.

[Tillydog]

I currently have the controls set to P=6, B=5, M=8, T=3, and V=6. A

How does it sound if you dial the presence down to 0?

Presence on 6 would be a bit ice-picky on my Express (maybe needed when "playing out", but not at home) - '0' is a flat frequency response.

I see you have 250k tone control pots, which I think will make the amp brighter. You could try dialling mid control back a little, too, as it covers quite a bit of the treble.

I have 250k tone pots in my Express and I like them very much. I realise that it's fairly meaningless to compare settings, but for reference, my "sweet spot" for a humbucker guitar is

Vol: 11:00
Treble :11:00
Mids: 13:00
Bass: 10:00
Presence 9:00
Bright switch on 100pF

After that, then I think you should try it on a different cab, just to see how much it affects the sound.

(You did say *any* suggestions... )

[bluesky636]

I currently have the controls set to P=6, B=5, M=8, T=3, and V=6. A

How does it sound if you dial the presence down to 0?

Presence on 6 would be a bit ice-picky on my Express (maybe needed when "playing out", but not at home) - '0' is a flat frequency response.

I see you have 250k tone control pots, which I think will make the amp brighter. You could try dialling mid control back a little, too, as it covers quite a bit of the treble.

I have 250k tone pots in my Express and I like them very much. I realise that it's fairly meaningless to compare settings, but for reference, my "sweet spot" for a humbucker guitar is

Vol: 11:00
Treble :11:00
Mids: 13:00
Bass: 10:00
Presence 9:00
Bright switch on 100pF

After that, then I think you should try it on a different cab, just to see how much it affects the sound.

(You did say *any* suggestions... )

Actually, your settings are not that far off from mine. Keep in mind, if you looked at the schematic, I used the "modern" presence control wiring that keeps DC off the pot, so it really doesn't start taking effect until after 1:00 or so. My treble is a little lower than your, but bass and mids are close. I don't need to use the bright switch at all with my humbucker equipped guitars.

Here is the frequency curve for my tone controls. Can't show the effect of presence, of course. I have confirmed that all controls operate properly over their full range.

The green curve is with a treble cap of 250 pF and the red curve is with a treble cap of 500 pF (which is what is in the amp now).

[img:921:628]http://farm6.staticflickr.com/5344/8847 ... cc2e_o.jpg[/img]

I have thought about dropping the 100K slope resistor a bit to bring up the lower midrange slightly.

For comparison, here is the curve using a 1Mohm treble pot:

[img:926:632]http://farm9.staticflickr.com/8532/8515 ... 0769_o.jpg[/img]

[Smokebreak]

How about preamp voltages? I think I mentioned this in my thread, but I increased the first dropper to 27K and it brought all my pre and PI voltages to match the voltage chart posted. This may not help the brightness for you, but it's worth a shot. It smoothed out my amp even though power tube plates were still 440. Seems like speaker swaps will be your best bet as suggested. I'm sure you know, but there are always cheap speakers on Craigslist, as obviously folks swap them around quite frequently. I managed to pick up a loaded 2-12 with a vintage 30 and another modern celestion for $150. I wired it stereo/ mono for different amps, and it makes a great a/b box too

[bluesky636]

How about preamp voltages? I think I mentioned this in my thread, but I increased the first dropper to 27K and it brought all my pre and PI voltages to match the voltage chart posted. This may not help the brightness for you, but it's worth a shot. It smoothed out my amp even though power tube plates were still 440. Seems like speaker swaps will be your best bet as suggested. I'm sure you know, but there are always cheap speakers on Craigslist, as obviously folks swap them around quite frequently. I managed to pick up a loaded 2-12 with a vintage 30 and another modern celestion for $150. I wired it stereo/ mono for different amps, and it makes a great a/b box too

Right, you went from 18.2Kohms to 27Kohms. Since I'm already at 22Kohms, I'm not sure it will make that big a difference. I also noticed as you did, that it takes a while for B+ to stabilize when using a zener dropper. But by the time I get everything set up and ready to play after turning the amps on, things seem to have settled and I don't notice any bad effects.

I think I am going to try upping the PI plate-to-plate snubber from my current 100 pF to 250 pF and see what that does first. I'll report back.

[Tillydog]

Keep in mind, if you looked at the schematic, I used the "modern" presence control wiring that keeps DC off the pot, so it really doesn't start taking effect until after 1:00 or so.

Fair comment - I had spotted the differences in the tone stack, but not the presence circuit (other than the different PI tail resistor value). I'd still dial the presence down to zero if the amp is a bit trebly, though.

I took the settings that I posted off the amp across the room from me, but forgot that I'd done the presonance mod. I kept the presence on or near zero before that. The presonance mod may be something that would help you.

Having tried both 250k & 1M treble pots, I think you get a more useful sweep with the 250k ones, but obviously that's no use if the amp is too bright for you!

[bluesky636]

Keep in mind, if you looked at the schematic, I used the "modern" presence control wiring that keeps DC off the pot, so it really doesn't start taking effect until after 1:00 or so.

Fair comment - I had spotted the differences in the tone stack, but not the presence circuit (other than the different PI tail resistor value). I'd still dial the presence down to zero if the amp is a bit trebly, though.

I took the settings that I posted off the amp across the room from me, but forgot that I'd done the presonance mod. I kept the presence on or near zero before that. The presonance mod may be something that would help you.

Having tried both 250k & 1M treble pots, I think you get a more useful sweep with the 250k ones, but obviously that's no use if the amp is too bright for you!

Actually, I have tried the full range of the presence control. One of the complaints of the "modern" configuration is that it really doesn't begin to make its effect known until 1:00 and beyond, so thee really isn't much difference between 11:00 and zero. I've looked at the "presonance" mod before. I'll take another look at it.

I agree about the difference in sweep between a 250K treble pot and 1M treble pot. There is a lot more midrange in the 1M than in the 250K which I found to be even noisier when I first tried the one meg. You'll also note that I only have a 100 pF bright switch. I did not like the 500 pF choice at all.

[bluesky636]

I just finished reading all three "Presonance" threads and think I will pass on that mod. It took me quite a while to get my amp stable (as mentioned in my first post, I can dime all the controls with no oscillations or squealing). I don't want to have to go through that exercise again.

I think my best course right now until I can afford some better speakers, would be to up the PI plate-to-plate snubber from 100 pF to 250 pF and maybe drop the 100K slope resistor down to 82K or 68K (56K might be too much for this amp though is sounds good in my 5F6A clone and modded Blues Deluxe Reissue).

[bluesky636]

I went ahead and upped the PI plate-to-plate snubber cab from 100 pF to 250 pF and dropped the tonestack slope resistor from 100K to 82K. The result seems to be a smoother treble and a slightly thicker lower midrange without any bass bloat. I wasn't able to crank the amp (its after midnight here in Virginia) but even clean it sounds smoother than before. I'll let her rip tomorrow during the day.

Thanks for all the suggestions.

[KellyBass]

I've had success by replacing the silver micas with polystyrenes of the same value.

[Bob S]

Speakers make a huge difference.
The 0.002uF/150k 3rd stage entrance is a good tweek zone too.
Good Luck - you'll get there.

[bluesky636]

I've had success by replacing the silver micas with polystyrenes of the same value.

Interesting.