Presence=more attack?

[Steven_nl]

Hi guys

I have a Ceriatone OTS in this layout:
http://home.kpn.nl/s.scholten17/ots-v2.jpg (thanks to Scott, Ayan and J Zucker)
I also use a loop made by Erwin_ve. Not sure, but the design may be from here.
With my setup I need to turn up the Presence to about 8 to add some brightness (to get rid of the blanket so to speak).
Unformtunatly I feel adding more presence also adds more attack which I don't like. Is this a correct observation?
For me the bright switch doesn't do the trick because it makes the low end thinner.

What would be an alternative to get the same result without adding attack? I did try a cap on the master. Maybe I should retry it in combination with a push pull.

Thanks.
Steven

[Bob-I]

You can adjust the value of the cap to change the frequency it acts on. Lowering the cap will raise the frequency. .68uF or .47uF will put the range up out of the audible range adding to the overtones, 2.2uF will bring it down into the upper mids.

Experiment. I personally like .68uF but that's me. BTW it will affect the tone slightly even with the presence on 0.

[Structo]

Bob are you talking about the bright cap on the Master volume or on the presence?

I generally run my Presence at 7-8 for medium volume settings.
I have a 1uf electrolytic cap there.

I believe Scott suggested using a 30pf to 47pf bright cap there on the master with the loop.
He also said that if you use a Dumbleator that the cap should be used.

Bob, or are you talking about the feedback cap (presence?)

The other thing you can do is adjust the the 330pf cap on the mid boost switch.
This cap is in series with the .002uf cap on the board to give you a 283pf total with the mid boost is off.

[dogears]

Try the following.

Reduce snubbers to 270pf or 330pf. I use around 270....

Raise bypass cap on V1B grid to a 500pf.

Reduce screen resistors to 470ohm or 500ohm. If using 6L6. It will change feel slightly.

Make sure preamp voltages are in 200V range.

Increase main filters a little. Top end is not as bright with 50uf total.

Let me know what you think.....

Hi guys

I have a Ceriatone OTS in this layout:
http://home.kpn.nl/s.scholten17/ots-v2.jpg (thanks to Scott, Ayan and J Zucker)
I also use a loop made by Erwin_ve. Not sure, but the design may be from here.
With my setup I need to turn up the Presence to about 8 to add some brightness (to get rid of the blanket so to speak).
Unformtunatly I feel adding more presence also adds more attack which I don't like. Is this a correct observation?
For me the bright switch doesn't do the trick because it makes the low end thinner.

What would be an alternative to get the same result without adding attack? I did try a cap on the master. Maybe I should retry it in combination with a push pull.

Thanks.
Steven

[talbany]

Presence/NFB definitely effects the attack.. Perceived tone is less bright but also the NFB used in your amp effects the dampening factor of the speaker softening it a bit (less throw) .. Bright caps IMO help to brighten the tone but to me doesn't really change that initial attack response of the speaker so to me it's more of a feel thing.. If your referring to a more percussive attack then you can file that in the tone category and therefore IMO address the bright cap issue.. There are things you can do to address both issues but we need to be clear on what type attack your referencing here...

Tony

[Bob-I]

Bob are you talking about the bright cap on the Master volume or on the presence?

Presence of course. The bright cap is small 22pF to 47pF. The presence cap is typically 1uF.

[erwin_ve]

Scott,
I 've exactly the same thing going with my amp. All the suggestions you made sure help(I have all of them in my amp) but the presence still has to be set high to get a good open non bass heavy sound.
The attack is no problem for me, I like it for its sitting well in the bandmix.

Every single D-clone I heard in the Netherlands has the same issue; crank the presence to get a good open sound. The only one I 've heard that doesn't need that was a Van Weelden.

I measured every cap and resistor in my amp, they are all on spec after replacing some off spec.

Last thing I haven't tried yet is replacing all shielded cable with a low capicitance one.
Maybe there's the clue; any off you guys have experience with that particular part?

Btw in my dlator builds I already use mil spec RG-178 coax(29.4pF/ft)

Try the following.

Reduce snubbers to 270pf or 330pf. I use around 270....

Raise bypass cap on V1B grid to a 500pf.

Reduce screen resistors to 470ohm or 500ohm. If using 6L6. It will change feel slightly.

Make sure preamp voltages are in 200V range.

Increase main filters a little. Top end is not as bright with 50uf total.

Let me know what you think.....

Hi guys

I have a Ceriatone OTS in this layout:
http://home.kpn.nl/s.scholten17/ots-v2.jpg (thanks to Scott, Ayan and J Zucker)
I also use a loop made by Erwin_ve. Not sure, but the design may be from here.
With my setup I need to turn up the Presence to about 8 to add some brightness (to get rid of the blanket so to speak).
Unformtunatly I feel adding more presence also adds more attack which I don't like. Is this a correct observation?
For me the bright switch doesn't do the trick because it makes the low end thinner.

What would be an alternative to get the same result without adding attack? I did try a cap on the master. Maybe I should retry it in combination with a push pull.

Thanks.
Steven

[bluesfendermanblues]

........Last thing I haven't tried yet is replacing all shielded cable with a low capicitance one.
Maybe there's the clue; any off you guys have experience with that particular part?
Steven

I changed all the shielded cable in my Ceriatone OTS to Geroge L (21 pf per Ft), which made the amp very bright.

have ordered the standard RG174/U cable (38pf per Ft) which will help soften the top end. I have the treble at 9 o'clock with a strat and a Thiele EVM12L cab.

George L will brighten your amp, but I would try Dogear's master vol bright cap. Its a much easier mod, Try 15p-47p to taste.

[erwin_ve]

........Last thing I haven't tried yet is replacing all shielded cable with a low capicitance one.
Maybe there's the clue; any off you guys have experience with that particular part?
Steven

I changed all the shielded cable in my Ceriatone OTS to Geroge L (21 pf per Ft), which made the amp very bright.

have ordered the standard RG174/U cable (38pf per Ft) which will help soften the top end. I have the treble at 9 o'clock with a strat and a Thiele EVM12L cab.

George L will brighten your amp, but I would try Dogear's master vol bright cap. Its a much easier mod, Try 15p-47p to taste.

Hi blues, thnx for the update on your use of coax! I already have a big bright cap on the master. Greetz Erwin

[bluesfendermanblues]

Anytime

[Steven_nl]

Presence/NFB definitely effects the attack.. Perceived tone is less bright but also the NFB used in your amp effects the dampening factor of the speaker softening it a bit (less throw) .. Bright caps IMO help to brighten the tone but to me doesn't really change that initial attack response of the speaker so to me it's more of a feel thing.. If your referring to a more percussive attack then you can file that in the tone category and therefore IMO address the bright cap issue.. There are things you can do to address both issues but we need to be clear on what type attack your refering here... Tony

Hi
Hard to discribe and I'm not quite sure I sully understand your remarks. Are you suggesting raising the Presence/NFB softens the damping factor of the speaker? I would expect raising the Presence lessens damping? Maybe I'm misinterperting "damping" (did a quick search on wiki, more complicated then I thought.)
Anyway, I think I am refering to the percussiveness of the attack.
I prefer the Presence to be set to about 3 or 4 for a softer atack. But then my amp is to dark. When set at 8 it sounds nice and open without being harsh, but when you hit a string it has that percussive pop.

Thanks guys for your expert advise.
@ Scott tnx for you detailed input. Erwin has helped me a lot already so he knows how my setup works. Mine is comparable to his.

@ blues. are you refering to the fx send and return cables or internal wiring?

[bluesfendermanblues]

.....@ blues. are you refering to the fx send and return cables or internal wiring?

Internal wiring. Changed six coax cables in total.

raising the Presence/NFB softens the damping factor of the speaker? I would expect raising the Presence lessens damping?

Hint: If you want a looser sound with less damping, try moving the feedback wire from the 4 omh tap to the 8 ohm tab. I prefer this for lower levels.

[marcos]

Another worthhwhile experiment :Try disconnecting the V1b feedback loop.This will make the amp more open and presence-y.However, the distortion will have a different, rougher
texture.Easy to try and revert if you don´t like it.You may have to adjust
the od entrance trimmer, because this adds a little gain as well.

Have fun, Marcos

[llemtt]

It seems that you don't have enough damping on your speaker, try a 3k9 feedback resistor instead of a 4k7, IMO that's the correct value for a 50w.

(moving the feedback tap from 4 to 8 ohm as suggested as the same effect)

cheers
teo

[bluesfendermanblues]

It seems that you don't have enough damping on your speaker, try a 3k9 feedback resistor instead of a 4k7, IMO that's the correct value for a 50w.

(moving the feedback tap from 4 to 8 ohm as suggested as the same effect)

cheers
teo

No, it has the opposite effect. Moving from 4 to 8 will provide lower damping and thereof looser bottom end and in effect looser attack.