rocket with tremolo circuit?

Express, Liverpool, Rocket, Dirty Little Monster, etc.

Moderators: pompeiisneaks, Colossal

User avatar
cbass
Posts: 4344
Joined: Sat Jul 23, 2011 6:17 pm
Location: Between Pomona & Bakersfield

Re: rocket with tremolo circuit?

Post by cbass »

pleasantbullet wrote:Will there be a problem, if I implement this tremolo circuit in my express... if i've used a lar mar mastervolume?
I don't know of anyone that's tried it. But there my be some issues with ticking or thumping considering the high gain nature of the express . I would Maybe try to mount the pots for the trem on the rear panel to keep the wiring away from the preamp controls.
DLR is a Captain beefheart wannabe
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

pleasantbullet wrote:Will there be a problem, if I implement this tremolo circuit in my express... if i've used a lar mar mastervolume?
Hi,

I have the circuit already in, with pots to the rear. The only thing ist to change the FS wire one step left. Allthough its a work of minutes, I´ll have it on weekend finished. Than I can tell what happens.
The Depth pot is wired like the Princetone Schem above. Rest like Jacky T.´s scratch which is almost same like the Fender circuit.

And yes, I have the LarMar too.

Let´s see, I will report.

Best

Hans-Jörg
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Jackie Treehorn wrote: The cathode follower will not add any voltage gain.
Ups, you are right. It has nothing to do with it. It´s for low output impedance. Comes from writing byside work :?

Please allowe me one detail more: as on 6g3 and Princeton Rev. Schemata one 1M goes to ground but the other (in line with the FS goes to cathode side of 3k3//25µ - not to ground side. This helps the tremolo start immediately after switching on - instaed of waiting for loading of the cath. bypass cap (see ValveWizzard).
http://www.valvewizard.co.uk/trem1.html
I read this 2 minutes ago 8) Not my skills :lol: .

Best
Hans-Jörg

PS: in V.W. is also a nice possibility shown to implement a flashing LED for visual frequency control - what a feature :D
Last edited by hans-jörg on Fri Jun 27, 2014 12:06 pm, edited 1 time in total.
User avatar
Reeltarded
Posts: 9926
Joined: Sat Feb 14, 2009 4:38 am
Location: GA USA

Re: rocket with tremolo circuit?

Post by Reeltarded »

hans-jörg wrote:
Reeltarded wrote:Sorry to disrupt this just to name the amp topology.

Tremocket

Sorry.
Hi
sorry but we are talking about the "Exprolo". :lol:

Hans-Jörg
haha :P
Signatures have a 255 character limit that I could abuse, but I am not Cecil B. DeMille.
Jackie Treehorn
Posts: 236
Joined: Thu Jan 20, 2005 4:54 pm
Location: New Orleans, LA

Re: rocket with tremolo circuit?

Post by Jackie Treehorn »

hans-jörg wrote:
Jackie Treehorn wrote: The cathode follower will not add any voltage gain.
Ups, you are right. It has nothing to do with it. It´s for low output impedance. Comes from writing byside work :?

Please allowe me one detail more: as on 6g3 and Princeton Rev. Schemata one 1M goes to ground but the other (in line with the FS goes to cathode side of 3k3//25µ - not to ground side. This helps the tremolo start immediately after switching on - instaed of waiting for loading of the cath. bypass cap (see ValveWizzard).
http://www.valvewizard.co.uk/trem1.html
I read this 2 minutes ago 8) Not my skills :lol: .

Best
Hans-Jörg

PS: in V.W. is also a nice possibility shown to implement a flashing LED for visual frequency control - what a featcher :D
I like the LED biasing. I don't think his description of a delay, at least with this implementation, is totally accurate, it's more like 2 cycles of pulsing at lower depth so you get a nicer transition/ramp up into the full trem effect. It's subtle but I like it. But it's your amp, so you should do it whichever way gives you the result you want.

I'm curious to hear how it works in an express. I think you may be looking at bigger plate loads/more b+ to get the depth up.
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Hello,
the good one: it works fine
but (the second one): when I connect, to test switching, the tip of the FS jack to ground, a big buzz, or better a Shrrrrrrr comes through the speaker.
And I cannot read more a cathode voltage. If I put the +Tip of my Volt meter (- is at ground) direct to the cathode, the terrible sounds is away, but the voltage don´t stabilize and jumping goes on. Bad grounding at cathode?
Or could it be crosstalks of wires - but wich one.

The picture down below - (please dont judge the built - its an Express with parts I had by hand and in that chassis been more than 2 amps before :roll: - but: the Express works very well! :)
- shows the wireing.
I guess the two black wires - one to ground, one to the FS jack tip - are approx. 5 cm (2 inch?) very close together and therefor ... or?
Whats your opinion?

The upper pic without Tremolo.

BTW. my Tremolo "build" is almost 100% same like 6g3 amp. And the mid lug of Depth/intensity goes to both Lug 3 (double pot 250k) of LarMar (for better understanding because the pic don´t shows it.


Best

Hans-Jörg
You do not have the required permissions to view the files attached to this post.
Last edited by hans-jörg on Fri Jun 20, 2014 4:47 pm, edited 3 times in total.
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Sorry, one more:
is it normal that the bias (mA at testpoint) is pulsing between the installed 32mA and up to 50 mA during Tremo action, without playing one note?

Oh, and I have only 2m speed pot - problem?

Best
Hans-Jörg
Jackie Treehorn
Posts: 236
Joined: Thu Jan 20, 2005 4:54 pm
Location: New Orleans, LA

Re: rocket with tremolo circuit?

Post by Jackie Treehorn »

The oscillating means it's working. It should stop when you ground the grid with the footswitch, of course.

So, tremolo on everything works right...when you ground the tip of the footswitch jack to turn off the tremolo, you get the buzz. When you then put the meter on the cathode to check the voltage, the buzz goes away?

I don't think it would be crosstalk. If you turn the depth knob all the way down, does that also take out the buzz?
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Hi Jackie,,

yes everything is working but only with the Voltmeter at the grid or cathode (makes no different).
The buzz don´t stops with Depth or Speed at Zero. Only a small diff. in sound of buzz.
Never had something like that: buzz goes away with Voltmeter on it.

AND: as long I don´t put the meter on grid or cath. there is no tremo Sound only the normal guitar sound! With Voltmeter hanged on everything works - w/o no tremo Sound and buzz when switching of. Weired!

Someone an idea?

May be I Need a capacitor some where to ground? I see at the Fender schematic there a cap in Addition hanging on the wire goig to the bias Point(2x220k).

Best
Hans-Jörg
Jackie Treehorn
Posts: 236
Joined: Thu Jan 20, 2005 4:54 pm
Location: New Orleans, LA

Re: rocket with tremolo circuit?

Post by Jackie Treehorn »

Ok, a couple preliminary ideas. One end of .1 cap with the blue wire looks like it's got less solder than the others, I 'd check that. Also the mounting bolt for the trem board looks like it's awfully close to that lead from the .01 cap. Maybe some heat shrink over that? They might be fine. I'm thinking grounding is the issue. If you've got some test leads, I would take out the ground wire you've got now, and see if another spot has better results. The can cap's ground point would be my first thought.
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Good morning Jackie T.
Thank you for your oversight.
The solder Point at 0,1 is checked but is fine though I resolered (resoldered every point). The screw is close but 1 cm away from leads.
I agree meanwhile with "grounding" as Problem.
Allthough the grounding Points are solid, I´ll try other places - can cap as you mentioned.
I connected the - Tip of the multimeter at the main gr. Point during testing and when I put the + tip to circuit it was all well. Looks realy I have to Change the gr. Point of circuit.

I´ll Report

Best R. and a quiet sunday

Hans-Jörg
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Hello,

very strange. It´s still the same. I tried different groundingpoints.
But when I put the +Tip of Voltmeter anywhere (cath, grid, anode) the trmolo works and no buzz when off. But it acts so even the minus is nowhere connected, means plus Tip solo used (no closed testing circuit - only plus tip). thats strange!

I have no more ideas. only: should I try to shield grid wire? Maybe the Voltmeter acts like a shield?

Hans-Jörg
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Well, grid is now shielded and it works very well.

I could have it easier and shield it from start.

But: yes this Tremolo circuit works with Express. with around -33 VDC. 300 V at anode and around 2 V at cathode.
No buzz more when off (needed only shield at grid because of relativ long grid wire)

Some Dates:

B+ (EL34 screens) 395 VDC
Anode:256 VDC
Cathode: 2 VDC
neg. Bias: -33VDC
Bias: 30 mA

Thanks for time and help,

very best

Hans-Jörg
Last edited by hans-jörg on Thu Oct 02, 2014 11:26 am, edited 2 times in total.
Jackie Treehorn
Posts: 236
Joined: Thu Jan 20, 2005 4:54 pm
Location: New Orleans, LA

Re: rocket with tremolo circuit?

Post by Jackie Treehorn »

Great news! I wouldn't have guessed shielding. I'm very pleased to hear the Exprolo is fully operational. Now we need some clips!!
User avatar
hans-jörg
Posts: 463
Joined: Mon Nov 01, 2010 10:11 am
Location: Vienna/Austria

Re: rocket with tremolo circuit?

Post by hans-jörg »

Jackie Treehorn wrote:Great news! I wouldn't have guessed shielding. I'm very pleased to hear the Exprolo is fully operational. Now we need some clips!!
Hi,
I apologize, but before August there is no chance for clips. Perhaps someone else will be faster, because they know now that your Tremo fits in an Express ( over 4800 clicks here :wink: )

Thank you
Hans-Jörg
Post Reply