Schaller Tremolo / Hearthrob Tremolo

Post by **modman** » 04 Nov 2007, 11:13

Thanks oldrocker,

Saw this coming... as the folder description says the post in here should contain schematics and any form of layout (which doesn't matter), but a schematic is essential.

I'm very grateful to MarkM for his contribution, but this is a grown up pedal forum, so we don't do anything without schematics. Even the best cannot make up what's going on from a parts layout.

It's kind of crazy to publish a layout that says 'based on Schaller Tremelo' in tiny letters and not publish that schematic. I simply don't build without accompanying schematic, because it's a hell to debug. And you learn hardly anything about the circuit at hand.

I thought these thing were obvious...

oldrocker · Post by **oldrocker** » 04 Nov 2007, 11:48

Well I did use the two 22uf caps and the 330K instead of the 470K resistor.that Mark's layout called out for. I wanted to make sure mine sounded like his.
I did a perfboard layout as I built it like I always do. I used a combination of the layout and the schem to make sure I got it right. I'm working on the offboard wiring now.

I'm at the debugging stage and as I expected I'm having problems with it. But I'm sure I will soon figure it out.

oldrocker · Post by **oldrocker** » 04 Nov 2007, 23:25

Okay. All done and IT WORKS IT WORKS. I may tweak it a little but it sounds and works great. Thanks Mark and all. I added the blinking LED too so that's cool.

nokaster · Post by **nokaster** » 05 Nov 2007, 12:03

i'm wondering how this hearthrob trem would sound with 4 germanium NPN transistors in it...
would it work with for instance AC187's?

maybe someone who has build it or is building it can try this out?

maybe some rebiassing will be required?
maybe the germaniums are to low gain to make it work?

just a thought... any input welcome!

oldrocker · Post by **oldrocker** » 13 Nov 2007, 05:33

Well no tweaking required with this. I had C6 and C9 swapped by accident. Swapped two leads and wham it sounds great. Nice job Mark.

John Lyons · Post by **John Lyons** » 14 Nov 2007, 16:01

Mark for some reason does not post schematics...or at least not that I know of. Schematics are key to understanding what's going on.

By the way, anyone heard from him in the last month? I emailed him a couple different times...nothing.

Glad you got your going Randall. It's a nice versatile trem isn't it?

John

DougH · Post by **DougH** » 14 Nov 2007, 16:05

John Lyons wrote:Schematics are key to understanding what's going on.

I agree. Layouts are of no value to me. I always do my own anyway and I don't do PCB or vero.

I breadboarded the schaller trem (it's called something else at ggg I think) and it is nice. I got the transistors for a vox repeat percussion which I was going to try next but haven't gotten around to it yet.

oldrocker · Post by **oldrocker** » 14 Nov 2007, 16:15

Thanks John, What I think Mark is trying to do is give people who build PCB's a layout resource to build from.
I haven't seen Mark in the forum in quite some time. I hope everthing is OK with him.
Hi there Doug, like you I only perfboard all my projects. No vero or PCB's either. Glad to see I'm not the only one.

bajaman · Post by **bajaman** » 14 Nov 2007, 19:26

Has Mark had an accident perhaps - hope he is still with us???!!!

nokaster · Post by **nokaster** » 15 Nov 2007, 22:27

does anyone, by any chance, have a vero board layout for the hearthrob?
or maybe the schaller tremolo?

i've learned a lot the last few weeks, but the schaller trem schematic or marks hearthrob layout are still a little tricky for me to turn them into a veroboard layout...

so any help appreciated!
(i know i could hve the pcb etched, but i kinda like building on perfboard!

)

oldrocker · Post by **oldrocker** » 16 Nov 2007, 16:22

I'm sure someone will be doing a vero layout for the Heartthrob sooner or later. It's too nice of a trem not to. Unfortunatly I don't do vero only perf.
On the one Schaller schem it shows if you put a SPST switch to ground from the base of Q1 (MarkM Layout) it will bypass the trem. What's nice is since I added the blinking LED on Q4 it will shut off when bypassed without doing anything else.
Here's mine boxed. P.S. I added the red power on switch. I ran out of stereo jacks at the moment.

p.eat · Post by **p.eat** » 02 Dec 2007, 15:30

Hi oldrocker,

how exactly did you implement the blinking LED? I did a search at aron's forum, but couldn't find a definitive answer.

thanks,

Peter

oldrocker · Post by **oldrocker** » 02 Dec 2007, 22:13

Hey p.eat, Positive side of the LED to the collector of Q4 and the other end to ground.

Markm quote "Place the cathode end at the collector of Q4 and the anode at ground."

You don't need to add this for the blinking LED. But the first transistor in the circuit that has it's collector going to the the other side of the first input resistor acts like a bypass when it's base is grounded and turns off the blinking LED.
So add a SPST switch to go from the base of that transistor to ground which is in parallel with the dwell pot to act as a bypass. It will shut off the blinking LED when used as a bypass.

vanessa · Post by **vanessa** » 04 Dec 2007, 02:51

Strange enough, my EH Pulsar build sounds identical to the samples John has. Some people complained about the Pulsar build having built it from the tonepad site, but I found an error in that layout and fixed it. Once I did it became one of the best tremolo units I've had to date. Mine sounds pretty darn close to the Hearthrob (at least in those samples) so I can guess why people are raving about the Hearthrob.

sosodef · Post by **sosodef** » 04 Dec 2007, 03:09

vanessa, few questions. Can you PM me the fixed schematic or is the tonepad schematic correct? I built one and its ok but has issues. The rate knob works really strange.

can you swap out the switch for a pot on the pulsar?

Also what IC did you use as I always thought the pedal needed a bit more headroom.

oldrocker · Post by **oldrocker** » 04 Dec 2007, 23:44

I've built my Pulsar on perfboard from Tonepad too and I always liked it. It is a great sounding trem. I never knew it had errors.

vanessa · Post by **vanessa** » 05 Dec 2007, 01:33

Yes there is a trace error. Some had issues, and some did not. But with the error corrected it works perfect.

This was my original post that will help you cut the trace and re-wire it. If you did not like the sound of it you should try these fixes, you'll love it.

"I wanted to share a couple of things (real quick) that helped make this a really great tremolo. First the tick that most people come across with this unit have built it from the Tonepad layout is that there is a trace error in the layout. You can see it if you look at Tonepad's schemo @ Q3's collector to R14. On the PCB Q3's collector connects to the wiper of R15. I have the schematic for the original version of the Pulsar and it's very similar to Tonepad's schemo so the fault lies in the PCB. Just cut the trace from Q3's C right before C8 and jumper that trace to R14.

And the modified pcb:

John Lyons · Post by **John Lyons** » 05 Dec 2007, 04:41

I built the pulsar a couple years ago. I made a few mods from posts in the build reports at tonepad and I liked it a lot. I sold it to a friend so I can't compare it to the heartthrob right now.

Thanks for the Fixed Trace Vanessa. There was a thread about this at DIYSBF a while back as well.

John

vanessa · Post by **vanessa** » 05 Dec 2007, 07:27

John Lyons wrote:I built the pulsar a couple years ago. I made a few mods from posts in the build reports at tonepad and I liked it a lot. I sold it to a friend so I can't compare it to the heartthrob right now.

Thanks for the Fixed Trace Vanessa. There was a thread about this at DIYSBF a while back as well.

John

No problem John, That's from the thread I posted over at DIYSBF a while back. I'm not sure why they [Tonepad] never updated the pcb layout but if you build one from the modified pcb layout I posted you'll be very impressed.

RiGLEY · Post by **RiGLEY** » 18 Dec 2007, 12:42

Is there a "tone-suck" or a volume-drop with this tremolo?
I'm looking forward to build this pedal.