Rocket a bit too dark

[hans-jörg]

Hi,
my Rocket clone is a bit too dark.
Because I have a lot diff. stuff in front (RJ Booster, G2 control, K.F. Master Nr2 or LarMar) I couldn`t implement the Cut controll (250k pot+0,004µF). Could this be a reason? Or is it only a high cut - means: I can dial hights out but not in.?
I´m considering to reduce the PI coupling caps from 0,047 to 0,022µF.
Or better the two before?
Allthough a bit bassy the sound is staight and hard until max of gain. Crunch comes up at the last third.
I know that the speaker is apart of the sound too. But I tried it on different ones.
Good punchy envan hard sound at full - but allways dark.

What do you suggest as the best solution to get more bright in?
Its rearley far away from a Voxy sound - more an Ampeg

Talking about the "ground sound". At second stage cathode I have a switchable 1µF. Thats fine, a small boost/coloure. But that is to add on, not for normal playing.

Coupling caps or a kind of bass cut?
Btw: Treble pot is not able to solve this.
I have everywhere the original cap sizes (0,047µF and 0,022µF+50pF in TS).


I forgot to mentione: guitar is a Epi Les Paul, a dark animal too

Best

Hans-Jörg

[cbass]

Try a smaller cathode bypass cap .68 , 1 uf or 2.2 uf

[hans-jörg]

Hi,
thank you.
Thats my point that I´m not shure whats the better solution. Because the sound is greate and very precise until max of Volume. This I dont want loose. Only bass content has to be reduced.
I know both ways: bypass caps or coupler.
You mean that would be tha way to keep the punch but reduce the bass.
I´ll try.

Btw: a second small question: what effect is it to rise R3 (first Rk wich is 1k5 regular) to 2k7 or to lower to 820 ohm.

Thanks again

Hans-Jörg

[cbass]

I like to reduce bass in the first stage when needed.Makes things a bit more focused.I think to reduce bass with smaller coupling caps you will need go much smaller like from .047 to .0047 to notice a big difference.

http://www.ampbooks.com/home/amplifier- ... capacitor/

[hans-jörg]

Hi,
thanks for the link.
Makes everthing mor clear for me.

Best

Hans-Jörg

[redshark]

I wouldn't change a thing from the original circuit.

You can max the cut control, all the way up!!

or try an alnico speaker, the celestion gold 16 ohms sounds fabulous!!

or 2 celestion blues in series 2 8hms for 16 ohms

[M Fowler]

Increase the 100pf silver mica cap on the volume pot to 250pf or higher.

I always add a two way bright switch on my Rockets by either leaving the 100pf on the volume pot and selecting my other caps to work with that existing 100pf cap or remove it and only have the two on the bright switch.

I always have bright engaged usually 500pf.

[hans-jörg]

I Thank you all for your replays.

Will try the bypass cap and the volume cap one after another.

But what I think is, that I made maybe a mistake in the entrance:
because this is a amp for my daughters FIRST band (she´s 16 years old) I put a 0,47µF cap direct to the entrance - means: guitar, cable, 0,47µ, tip of the jack in series. But there is the pull down 1M resistor to ground too. Is it not a high cut? The reason was to protect her from any accidental DC. I think that was too much.
She loves the tone and growling sound and don´t want to change anything (stile: Arctic Monkeys)- but thats no rocket sound and I think when she gets the rearly one she will love it too.
I built her a good old Rangemaster which she uses now between guitar and amp - allways in ON position.
That shows me that she needs some heights

Am I right that I´m wrong with this 0,47µ?

Best

Hans-Jörg

@redshark: there is no cut control as I wrote in my first post. There was no more space for an other pot in front (in the back too - there´s line, recording and headphone exits ans some switches. Its a very compact amp)


+some pics, sorry they are 10 months old - therefore no plates on

[M Fowler]

Was that .47uf cap put there to knock down noise? It will definitely sound brighter without it.

If your getting input noise, isolate the jack from the chassis.

[hans-jörg]

Was that .47uf cap put there to knock down noise? It will definitely sound brighter without it.

If your getting input noise, isolate the jack from the chassis.

Thank you Mark. I allways thought so, but coudln`t verify it because my daughter dont wants to return the amp - evan not a day. So I have to do it once in the dark

You see the red cap right above on the corner of the chassis. It´s in series withe the input signal. So my idea was not to shunt high frequece to ground but to protect ev. DC on his way to guitar.

But I´m now shure too that this is may problem/mistake.
The amp by itself is perfect and stable (what else).

I know my wireing is chaos pure but very stable - no noise at all.

Kind regards
Hans-Jörg

[Tillydog]

I don't believe that the cap in series with the input signal will have any audible effect (but is a good safety feature!).

I very much like the cab, btw!

Any way you could have made a wiring error around the tone stack?

[hans-jörg]

Hi, you are right,
when I bypass this cap thee is no difference. Nevertheless I put it out.
I gave 0,68 at first stage and a switchable 10µF at the second.
Now ist more that what my daughter Needs for "her" Sound.
And I went down from 133 Ohm each side (two tubes) to 100 Ohm. What gives a 50 Ohm if both PS sides would have only one resistor and one cap.
Now there is at each side 100ohm plus 220µF cap. This will give an other pepper. Before there was less than 10 Watt dissipation. In the evening I will check the new diss.
I think, the lower bypass cap will meet better with the speaker which she use: WGS ET65 12". Ist a more darker speaker I think.
If this all dont works - I have to give her my personal old Italian Alnico 65Watt speaker. Whats not rearly my intentiion

Best
Hans-Jörg

BTW: Cab: Amp and cab was a Christmas present from me and I wanted she create her own cab. So I tolexed it with Ivory Tolex and bought her 20 dif. colloured permanents to write or paint whatever she wants on.

[Gaz]

Hans, you are the coolest dad ever. That head box looks awesome too. I think it was wise to reduce the first bypass cap like you did, however make sure the dissipation isn't too high with the new 100R resistor. I think right around 100% dissipation is good (12W), but any higher is foolish with modern tubes.

[Turbojunkie]

Hi Hans-Jörg,
I replied to your other post about Rocket speaker choices before I read this post about this being your daughter's amp...you are truly an awesome Dad for doing this for her, really cool! The head cab idea is great, I love it!
I just played my Rocket a bit, and am wondering if the fact that you couldn't implement the "Cut" control could be it?...Is the amp completely missing any or all of that circuitry? Being such a newbie, I'm not sure exactly how that might affect the amp, but with my Cut control off, my amp is WAY too dark as well, even with Treble dimed...
I was checking out the schematic that Colossal (I think...maybe Rhinson?) drew up for the Xits X10 amp, and saw that the theory with that amp is a fixed resistor and cap that gives you the setup of a normal Vox/Rocket-style Cut control set at halfway, without needing to install a control pot in the amp.....
I'm very new to amp building, just learning, so I apologize if any of this sounds ignorant, just trying to make sense of this stuff myself

TurboJunkie

[Turbojunkie]

If my post above made any sense, here's the page for Colossal's schematic download with Rhinson's fixed Cut idea....

https://tubeamparchive.com/viewtopic.ph ... &start=105

Good Luck with the amp, I hope you get it sorted for your daughter, whatever the problem might be!

TurboJunkie