I purchased a Vox Escort amplifier a little while back, and it's quite a cool little transistor amplifier. It's a simple transistor amp from the early seventies with an IC-based amplifier. It screams when turned up.
Here's my original post with more information on the amplifier (including a schematic).
Anyway, I thought I might try recreating one, albeit in a different format, ideally one that can run on a standard pedal power supply or a regular 9v battery as a practice amp.
I recently purchased the amplifier IC, which is still readily available at a reasonable price - so here it is, a work in progress. The vero layout may go through some evolution as I play with this. I'm not sure if I will try to fit it in a Hammond enclosure or a small wooden box.
Project Intent
- Create the sound of a small speaker that's being driven into oblivion
- Small enclosure for an amp: a Hammond or a small wooden box
- No expensive components
- Not mains powered, battery or pedal power supply
It will spend some time on the breadboard first, so I may also tweak some values to suit my preferences and tune it to the enclosure I end up using (whatever that may be).
NOTE: This has successfully been built by Ian, see comments below. I actually made some mistakes and cooked mine...
VOX ESCORT AMP - VERO LAYOUT
looking forward to your posts, Happy New Year
ReplyDeleteHappy new year Colin. This project could go in a number of directions…. Still need to find a little speaker and think about a box for it.
DeleteHow is that 1kuF laid out?
ReplyDeleteHi Markie. It’s on its side with each leg on row 5, either side of the cut on column 25.
DeleteHi Ding. My Vox amp is nearly fifty years old - it has this chip and is still going well. Doesn’t look like Vox did anything special with it. It doesn’t even have a heat sink
ReplyDeleteHi Andy, did you manage to get this working. I recently put a Mullard 1W amp together and its really cool with a treble booster. This Vox looks good also!! Cheers
ReplyDeleteHi Ian - I accidentally cooked the IC and haven’t got around to getting back to this project. Do you have details on your Mullard project anywhere? Would love to have a look.
DeleteHi Andy, I took the following schematic
ReplyDeletehttps://www.dropbox.com/s/nktve7gnp68fk3s/Deacy%20Style%20Amp.png?dl=0
then discovered there was already a stripboard layout using a similar schematic at
https://paulinthelab.blogspot.com/2012/06/brian-may-deacy-amplifier-stripboard.html
Its probably not 1W but it is loud enough for messing around in the house. Stick a treble booster in front and it sounds real good. I tried a couple of speakers - first was an old 4 ohm 8 inch speaker (taken from an old hi-fi), then an 4 ohm 8 inch 15W celestion and the old one sounded better but the Celestion was slightly louder
DeleteYour Vox project looks pretty cool, I've managed to find some IC's so will have a go when they arrive
1w can be loud enough for practice at home. Thanks for the links too - hopefully I’ll get back to this another time.
DeleteCheers Andy, looks like a great project. It certainly is nice to do something a little different instead of pedals.
ReplyDeleteI hope it works for you - if it sounds anything like the Vox I’d be happy. It really is a very surprising little amp.
DeleteHi Andy, finally got round to building this and it worked first time - it's loud and very dirty.
ReplyDeleteI used a 4 ohm vintage hi-fi speaker at first and I could feel, if I turn the volume right up, it would end badly. In the end I settled for a decent 4 ohm guitar speaker which could handle full volume.
Transistor was a 2N3904.
Did I mention, its really dirty!!!
Slight difference between channels - in the Brill channel, if you turn the tone all the way it screams. Normal is fine.
It's a fun amp to play with, I may try a couple of other speakers. I'm using a 6.5 inch at the minute and I feel a bigger one would sound better.
Awesome - I may have to revisit this. The original Vox only has a small box, and the enclosure is a sealed box, roughly the same size as a modern Pathfinder.
DeleteMine is really loud and gets dirty, which is where it sounds best.
Hi, did you use Andy layout, its work fine (verified)?
DeleteHello - Ian built it using this layout and it works. See comment above.
Delete