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BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318 [documentation]
Posted: 09 Mar 2018, 09:46
by bajaman
Hot off the drawing board - vero layout to follow shortly
This is the amplifier that after the VOX AC30 changed the sound of British rock for ever - based on the circuit of the 1959 Fender Tweed Bassman it used the European EL34 entode output tubes because they were a lot easier and most probably a lot cheaper for Jim Marshall to purchase in post WWII Great Britain.
enjoy and have fun
bajaman
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 09 Mar 2018, 15:16
by Frank_NH
Whoo hoo. I'm running out of TL064s!! Thanks again.
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 09 Mar 2018, 16:31
by HEAD
Frank_NH wrote:Whoo hoo. I'm running out of TL064s!! Thanks again.
... still waiting for mine to arrive. Running out of 100k pots, too!
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 10 Mar 2018, 03:39
by bajaman
- Baja Mars Hall 1959 vero cuts.png (7.4 KiB) Viewed 7212 times
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 10 Mar 2018, 15:20
by roseblood11
What's the advantage of the tl062 over the 072 or other opamps here?
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 10 Mar 2018, 16:45
by HEAD
... lower slew rate -> less harsh sound.
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 10 Mar 2018, 23:59
by Frank_NH
Quick question. Did you intend to have 100K to ground for the JFET buffer?
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 11 Mar 2018, 08:45
by bajaman
Quick question. Did you intend to have 100K to ground for the JFET buffer?
Good spotting - Yes - I found it improves the signal to noise ratio as the fet is now running at a much lower current.
cheers
bajaman
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 11 Mar 2018, 18:18
by Frank_NH
OK. Yes, 100K will lower the current flow, though wouldn't the higher resistance introduce more noise?
Well I can simulate it in LTspice and see. Thanks!
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 13 Mar 2018, 10:23
by 287m
first try in perf
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 13 Mar 2018, 12:33
by FausterCraster
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 14 Mar 2018, 00:20
by gght
Anyone have clip to listen to this??
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 14 Mar 2018, 02:57
by bajaman
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 14 Mar 2018, 05:00
by bajaman
some pictures of my build - recycled enclosure again
cheers
bajaman
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 14 Mar 2018, 18:21
by gght
Sweet
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 21 Mar 2018, 18:37
by HEAD
287m wrote:first try in perf
Edit: Made a mistake and fixed it.
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 22 Mar 2018, 08:01
by 95H
Hallo,
what type of capacitors are used away from the 1uF multilayer ceramic?
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 22 Mar 2018, 11:59
by 287m
95H wrote:Hallo,
what type of capacitors are used away from the 1uF multilayer ceramic?
MLCC, like
this
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 22 Mar 2018, 12:52
by 95H
287m wrote:95H wrote:Hallo,
what type of capacitors are used away from the 1uF multilayer ceramic?
MLCC, like
this
The question was what type of caps for the other values than the 1uF. Except electrolyte .
Re: BAJA Mars Hall 1959 plexi amp overdrive pedal 9v 090318
Posted: 22 Mar 2018, 13:16
by 287m
I build all with MLCC, because all i have.
But you can use poly box caps and/or ceramic for some pF value
