SJ Effects. Custom Audio Devices Handmade in Nottinghamshire.

raulduke

Hi Guys, just thought I'd give a quick mention to the stuff I build...

I build custom guitar and bass effects for my clients, ranging from simple switcher boxes to analogue multi-fx units.

I offer a small range of ‘standard’ pedals that are available to order for an affordable price. I also do a lot of custom work for my clients which is priced on a per-job basis.

I am based in Nottinghamshire, UK, and all my pedals are handmade by myself and are built using quality PCB’s, and high quality components.

If you chaps are interested you can take a peek at my website here:

http://sj-effects.com/

Cheers!

Steve.

Some examples of my work:

guitargeek62

Great looking builds, how much would one of those silicon FF clones set me back?

raulduke

Cheers!

I'll PM you with the details on my Fuzz Face builds (I can build them for a variety of specs and looks).

Thanks for the interest,

Steve.

juansolo

Steve does some very cool effects!

raulduke

Cheers Juan!

I'll upload some other recent builds soon.

monquixote

You aren't breaking any rules to show off your products. 

The only thing we don't allow is people doing business sales (the odd second or clearout is fine) or spamming press releases. 

Great looking pedals BTW.

raulduke

Thanks for the heads up and compliments dude!

Here's another one I finished over the weekend.

It's a B+M Champion Fuzz Unit clone.

The original fuzz was made famous through it's use in Edwyn Collins 'Girl Like You' (great song).

This one went in a giant enclosure because, well, why not

juansolo

Oh hello, that's one I haven't built. Does it sounds as good as it does on the track?

raulduke

It gets there definitely. You should check it out mate.

Need to try it straight in to my recording interface DI'd though to really emulate the tone (apparently Edwyn went straight to desk for those parts).

The filter used on some of the parts is more of a mystery. Sounds like a mutator or some other studio filter to me (rather than a mutron).

juansolo

Added to the todo list

raulduke

Another recent build for a customer.

It's a Tremolo and Vibrato combo' pedal.

These are proving quite popular. Built a few of them now (got one going together on the workbench right now).

raulduke

Latest off the line from the bench; the Goldcrest Boost and Eq.

Been working on this one for a while now. It started out as a discrete JFET based design, but I eventually moved over to an op-amp based circuit.

I also simplified the EQ significantly (it was originally a three band eq with sweepable mid frequency). I figured sometimes less is more in terms of controls available on pedals.

I am building these as 'standard pedals', and the small batch that I have sold + also sent out for testing are going down well.

It uses expensive, 'cork sniffer' OPA2134 opamps for the boost and eq circuits (the eq is based on the old tilt eq circuits).

Being honest I didn't think I would be able to tell the difference vs bread and butter TL072's etc. but there was a noticeable difference in clarity with them (and also noise floor), so in they went.

jpfamps

raulduke said:

Latest off the line from the bench; the Goldcrest Boost and Eq.

Been working on this one for a while now. It started out as a discrete JFET based design, but I eventually moved over to an op-amp based circuit.

I also simplified the EQ significantly (it was originally a three band eq with sweepable mid frequency). I figured sometimes less is more in terms of controls available on pedals.

I am building these as 'standard pedals', and the small batch that I have sold + also sent out for testing are going down well.

It uses expensive, 'cork sniffer' OPA2134 opamps for the boost and eq circuits (the eq is based on the old tilt eq circuits).

Being honest I didn't think I would be able to tell the difference vs bread and butter TL072's etc. but there was a noticeable difference in clarity with them (and also noise floor), so in they went.

The OPA2134 is indeed much quieter than the TL072 (in fact the TL072 is one of the noisier op-amps on the market with respect to voltage noise).

Unlike the TL072 the OPA2134 doesn't phase invert when driven near to it's negative rail. My guess is that this doesn't sound very good.

raulduke

It's a very nice opamp for sure. It sounded better than other opamps too (including ne5532 which are nice sounding devices in my opinion). Burr brown stuff is quality in general (although they are TI now).

jpfamps

raulduke said:

It's a very nice opamp for sure. It sounded better than other opamps too (including ne5532 which are nice sounding devices in my opinion). Burr brown stuff is quality in general (although they are TI now).

The only time I've employed an OPA2134 was fixing a pedal that had one in (can't remember what it was. but apparently it was a key feature of that design).

When used in circuits optimised for its use, the NE5532 is capable of lower noise and distortion performance than the OPA2134. However what this translates to in the sound of a pedal, who knows?

Looking at the schematics of various pedals, it does seem that they are not designed for lowest possible noise, so it's possible that a JFET input op-amp may work better in many circuits.

Have you (or indeed anyone else) tried the LM4562? This gives superior performance in terms of noise and distortion when compared to the NE5532.

raulduke

I think a little bit of noise is just an accepted effect with overdrives, distortions and fuzzes. Your amplifying the signal to the point of clipping, so noise is going to be inevitable.

I used an LM4562 in a buffer I built and it sounded great to my ears (THD of 0.00003%!). Hardly a thorough work out for the device though. I think in most scenarios the NE5532 is a great choice. It's low noise, affordable, and it sounds good.

I'm a big fan of the JFET in general. I bought a shed load of 2N5457's before they were discontinued by Fairchild. JFET Overdrive circuits sound really nice to my ears (the higher noise trade off is worth it for the tone in my opinion).

This is quite an interesting article on noise (and mentions the performance of the LM4562): http://sound.westhost.com/noise.htm

Great amps by the way. I've had my eye on the Sir Charles for a while!

jpfamps

raulduke said:

I think a little bit of noise is just an accepted effect with overdrives, distortions and fuzzes. Your amplifying the signal to the point of clipping, so noise is going to be inevitable.

I used an LM4562 in a buffer I built and it sounded great to my ears (THD of 0.00003%!). Hardly a thorough work out for the device though. I think in most scenarios the NE5532 is a great choice. It's low noise, affordable, and it sounds good.

I'm a big fan of the JFET in general. I bought a shed load of 2N5457's before they were discontinued by Fairchild. JFET Overdrive circuits sound really nice to my ears (the higher noise trade off is worth it for the tone in my opinion).

This is quite an interesting article on noise (and mentions the performance of the LM4562): http://sound.westhost.com/noise.htm

Great amps by the way. I've had my eye on the Sir Charles for a while!

Rod Elliot's site is indeed excellent.

Re buffers with the typical guitar source impedance, a JFET input will be lower noise.

I've been using a JFET/BJT complimentary feedback as a buffer, combining the benefits of a JFET input with the extra gain of the BJT to linearise the output. 

I found this circuit in some JFET application notes, and has been used in the ADA MP-1 pre-amp.

http://i.stack.imgur.com/yYHXp.png

The gain of this circuit is still a gnat's below unity (although much better than a JFET source follower), but can be increased to unity (or indeed beyond) by putting a small resistor (22 ohms seems to work for me) between Cout and the JFET source.

To improve on this circuit I was thinking of combining a JFET and op-amp to take advantage on the extra gain and load driving capability of the op-amp with high input impedance and lower noise of the JFET. I've not yet got this to work well.

The discreet circuit could be improved (using a current source instead of a resistive load for example), or perhaps simply using a OPA2134 op-amp would be the all round better solution.

Or possibly this is all overkill for guitar use.......

raulduke

That looks interesting. Thanks for the schem.

Bi-Polar supplies are becoming more common with pedals etc. so ignoring the parts required for that, the parts count is relatively low for the buffer.

I've got LT Spice (great software) so I'll have a go at simmulating it myself.

Thanks again for the heads up!

jpfamps

raulduke said:

That looks interesting. Thanks for the schem.

Bi-Polar supplies are becoming more common with pedals etc. so ignoring the parts required for that, the parts count is relatively low for the buffer.

I've got LT Spice (great software) so I'll have a go at simmulating it myself.

Thanks again for the heads up!

I've got an old SPICE interface which is useful, and I've simulated this circuit in it before using it and it works fine from a single supply.

I'm always fairly paranoid about oscillation so use a gate stopper on the JFET and a 100 ohm resistor on the output.

I've got the schematic drawn up somewhere with the circuit values I've used; I'll try to post it.

The performance is vastly superior to the stand JFET source follower for very little extra expense, and even better can be made exactly unity gain.

Oh, and thanks for the kind words about our amps.