SOLSTICE: Even easier PT2399 reverb!

[Jdansti]

David-

Thanks for the information about the regulators. I suspected the same, but I think I saw 5V on the output after the Solstice stopped working.  I'm going to substitute a 7805 anyway and see what happens. If I understand you correctly, the temp rise on the TO-220 case should be small enough to not require a heat sink. Is this correct?

I'd say at regulated 9V you won't need heatsinking.

david

Thanks!

[lpanagis]

Hi, I just wanted to let you know that I tried to make my own (smaller real estate) PCB following the schematic and realized that it is wrong: Fsb should be grounded and Fsc should be connected to R22 and R23. It would be nice to have another look at the schematic to check for other errors that could have slipped in!

[Jdansti]

Hi, I just wanted to let you know that I tried to make my own (smaller real estate) PCB following the schematic and realized that it is wrong: Fsb should be grounded and Fsc should be connected to R22 and R23. It would be nice to have another look at the schematic to check for other errors that could have slipped in!

I noticed that too and forgot to mention it.  After I corrected the switch wiring, it seemed to operate fine other than going 100% dry after about 10 minutes.  I hope that switching to the larger 5v regulator will fix this.

[lpanagis]

This was actually the second reason I wanted to make my own PCB: I'll use an LM7805 instead of its little brother. It can easily handle 1A and with its tab I can mount it on the aluminum enclosure and hopefully it will be kept cool. The little 78L05 is a 0.1A device and in the enclosure where convection cooling is practically impossible it can shut down after a few minutes. If the PCB design allowed, epoxying the regulator to the enclosure would alleviate the problem a bit but if you gig with it and it gets hot, it would still shut down on you. I believe an LM7805, mounted to the enclosure is the way to go...

[induction]

I just ran into a similar problem I find that mine works for about 10 minutes and then it sounds 100% dry. The 78L05 reglulator becomes so hot that I can't touch it. If completely power it down and wait for about an hour, it works fine again for another 10 min.

I don't know if you've sorted this yet, but I've had similar problems with PT2399's in the past.  The hot regulator was caused by the PT2399 locking up, and a bigger regulator didn't help.  I followed the advice from here: http://www.diystompboxes.com/smfforum/index.php?topic=93868.msg816797#msg816797 and haven't had any more trouble so far.  Instead of a voltage divider, I just put a 1N400x between the output of the regulator and pin 1 of the PT2399, which dropped the voltage to ~4.3 V.  Worked like a charm.  I can't hear any difference in the result, but I used it for a delay, not a reverb, so YMMV.

I'm planning to breadboard this soon.  The clips sound very nice and un-springy.  Thanks, Merlin!

[bluebunny]

Small resurrection here...  I built my Solstice a couple of weeks ago, but been away on business so unable to play much with it.  Seems it's not working entirely as expected.

I'm getting reverb for sure.  And the reverb changes as I move the pot and the trimmer.  So I'm pretty certain both PTs are doing their job (no sign of overheating, latching up, etc.).  But it's a bit on the quiet side.  And the reverb is there whether it's switched on or not!  So I tried taking the JFET out, expecting nothing but dry.

Reverb.  

And it's a whole lot louder - nearer to the unity I was expecting.  Trick #2: replaced the JFET with a jumper, expecting wet signal to be always on.  Back to quiet reverb.  Hmm...

So is it possible to get signal into the PTs via the RHS of the circuit, i.e. via P1?  And is it possible to suck signal bigtime by letting it through on the LHS, i.e. R9, et al.?

I might have to resort to probing voltages.  I'll need to be brave.  The last time I did this, I managed to turn a sub-mini tube into a light-emitting triode.  Briefly.  

In the meantime, any thoughts?

[merlinb]

And it's a whole lot louder - nearer to the unity I was expecting.  Trick #2: replaced the JFET with a jumper, expecting wet signal to be always on.  Back to quiet reverb.  Hmm...

So is it possible to get signal into the PTs via the RHS of the circuit, i.e. via P1?  And is it possible to suck signal bigtime by letting it through on the LHS, i.e. R9, et al.?

Does P1 still allow you to turn the reverb down to nothing, either with of without the JFET? Pretty sure you've just wired something up wrongly.

[stevie1556]

I love my Rub A Dub reverb from 1776 effects, but the belton brick isn't cheap (and I already killed one!)

Definitely got this and the Equinox on my build list, especially as I have just received a bunch of PT2399 chips!

Thanks for another great layout Merlin!

[bluebunny]

Does P1 still allow you to turn the reverb down to nothing, either with of without the JFET? Pretty sure you've just wired something up wrongly.

Yep, P1 varies the reverb amount as expected.  It's just that the switch/JFET isn't having much effect - except attenuating the signal into the PTs when it's there.  

Will get out my fine-tooth comb...

[bluebunny]

Ah ha!  She flies!   

Thanks for asking the right question, Merlin!

. . . Pretty sure you've just wired something up wrongly.

I was working from my own perf design.  I'd been over it time and time again and was convinced it was OK.  (And indeed, it was.)  The error came when this myopic tw@t translated the good design into a slightly flawed piece of board!  I had a run of five pads where two were connected, then a gap, then three were connected:

(1)=(2) (3)=(4)=(5)

Sadly, I misread my own layout and connected them all together:

(1)=(2)=(3)=(4)=(5)   

The short explained everything: low levels, reverb on always, ...

Anyway, all's well that ends well.  Working perfectly now.  Thanks for a neat design, Merlin, and thanks for the prod in the right direction.

[attila]

Hello

I have bought all the parts for this build....and I am a total Noob at this ... Would like to know if anyone can help with a Vero board layout PLEASE ....  I could go the Equinox route as well if that were available

Attila 

[MrStab]

erm... i think i've got this working properly. it's more delay-ish than i've expected, sounds very bathroom-like with the trimpot all the way down (well, its on an external pot). it has that kinda "pop" with the attack, the trademark of a really short delay time (less so on the neck pickup than with the bridge).

i understand the PT2399 has its limitations, but does that (probably unhelpful) description sound about right? lol. roughly, how did everyone else set their trimpot?

[Jdansti]

I replaced the trim pot with a regular one and called it a feature! 

[MrStab]

I replaced the trim pot with a regular one and called it a feature! 

that's totally what i was thinking! lol

i'm having problems with switching - further back in this thread it was mentioned that the switch wiring was wrong, ie. it should be ground to lug 2 and JFET etc. to lug 3, but this just shorts my power supply. i'm using a J201. it didn't switch at all in the original configuration (had to jumper it for testing), so i don't know what's up.

[MrStab]

ah... see, what happened was a secret lab in an undisclosed desert location fired an experimental gamma ray device into my brain which caused me to forget that JFETs don't work like NPNs and therefore totally overlook the pinout. that's surely the only plausible explanation. surely.

... no shorting anymore, but also no switching. boo. and no LED - that only comes on if i wire the switch as per the schem, but if i do that, then the Off position shorts.

Edit: not working anymore even when jumpered, nevermind guys i don't wanna waste your time with my scatterbrainedness.

[Jdansti]

It's been a while, but I seem to recall a switching issue with mine. I think I went back to Merlin's build docs and wired it as shown in my notes on his images:

[MrStab]

thanks, John - that seems to be how i had it, i'll go back to that if i get things going again. in my frustration i've just omitted the switch altogether for now. i fear i might've killed both PTs, despite my best efforts not to. it's the only explanation i can think of - haven't probed yet as it's late, but i get a buffered clean sound in both on & off states. *sigh*

[MrStab]

got the reverb working again, plus a feedback pot, and i'm still having problems with switching. i've tried a few 2n5952s and a J201 (i'm aware the former may need to be hand-picked). here's something else i don't get, and i don't doubt it's a dumb question: if FSa is 9V+ and FSb is ground, it shorts the power supply. i must be overlooking something?

[MrStab]

after looking at the Equinox schematic, i decided to try using an NPN instead, but first i replaced the 1n4148 with a 10K resistor (also as per the Equinox) and alas, it works when i hook up 9V to the Gate of the 2n5952. was that diode backwards? i'm guessing probably not as no-one mentioned it and i'm not that wise, but in any case it seems to work now. is this bad? will it give me AIDS or cause a thermonuclear war? i assume the diode was there for a good reason

[merlinb]

if FSa is 9V+ and FSb is ground, it shorts the power supply. i must be overlooking something?

Hmm, I think I labelled the layout image wrong. FSb and FSc are labelled the wrong way- swap them over to match the schematic.