Skip to main content

Plug-in buffer

Still on holiday from work, but my back is on the mend thankfully.

I've been tinkering with another pedal (more to come) and it's a bit of a strange one. It has an unusual switching mechanism which means that it's not bypassed in the usual way. I'd heard others report that this effect suffered volume loss when engaged, but my breadboarded circuit suffers from volume loss when in the signal path, engaged or otherwise. In fact, the volume difference between on/off states is negligible in my case.

I wanted to try a few things, and one was whether buffering the effect would make any difference. So I conjured up an idea to make a plug-able buffer that I could use for this purpose now and in the future when breadboarding circuits.

The circuit I used was the bi-polar transistor buffer circuit described in the link, and here is what my finished item looked like.

plug-in buffer
In the end, this particular circuit didn't benefit from the addition of a buffer, but that's another story.
Labels:

Comments

Post a Comment

Popular posts from this blog

Vox Pathfinder 15 Tremolo Repair

Last year, I snapped up a Vox Pathfinder 15 (non-reverb) combo amplifier from ebay. The seller was a charity shop, and the amplifier was listed as "untested", so I was taking a bit of a gamble, but figured I'd have a good chance of being able to fix it it it wasn't working, and cosmetically, it looked almost mint. When it arrived, I plugged it in, and as you guessed, it was not working. Barely any sound, and what sound there was was horribly distorted. One thin I did notice was the the power on LED was not aligned correctly with the hole in the back panel, so I did quickly took it apart, and realigned the potentiometers and LED indicator, but didn't have a look in detail at the circuit. I put it back together, but the problem remained. My guess was that the problem was the famous "cambridgitis" (just google that term and you'll find all about it). Basically, a problem where the optocoupler that controls the tremolo circuit fails. A common failure
1 comment
Read more

Vox Pathfinder 10 and Pathfinder 15 Simulation

I've got a Vox Pathfinder 10 amplifier that I bought a couple of years ago, and I love it. It's a great little amplifier, but I don't care for the distortion channel, it just sounds harsh to my ears. There are quite simple modifications that can be done to this amplifier to remove the clipping LED's and increase the boost of the clean channel (check out Ben Craven's mods  for details). I'd been considering doing some of these, but whilst researching the subject, I discovered that the currently out of production (as at Nov '18)  Pathfinder 15/15R generally receives a lot more love than the Pathfinder 10. I found schematics for both the PF15 and the PF15R online, and saw that there were a lot of similarities between the PF10 and the PF15, particularly the earlier non-reverb PF15. The PF15R (with reverb) is quite a bit different after the first two opamp stages. I thought I'd model both the PF10 and PF15 pre-amp stages in LTspice  to see how they compar
3 comments
Read more

Pete's Bazz Fuss

It's been ages since I built an effects pedal, so to get my soldering chops back up to speed, I decided I'd build a simple fuzz pedal for my long-time friend Pete as a surprise present for his impending birthday. The circuit I chose was the Bazz Fuss (yes that's the correct name)  which you can read about here if you care to. I went for the basic v1.0 of the circuit and used a 2N3904 for the transistor, and boxed everything in a 1590A sized enclosure. Despite a number of stupid mistakes that I had to rectify, I got it all done and boxed within a day, complete with lo-fi graphics. Here's a gut-shot. gut-shot And here is the finished item. lo-fi graphic It sounded OK when I played it although it needed the volume knob maxxed out to get the best out of it. Maybe a higher gain transistor would have been better still. I'm pretty sure Pete will like it though.
Post a Comment
Read more