Hi all. First post! I am looking to build the first 2 stages of the AB763 circuit, add a small twin reverb and a direct out and put it into a rack space for recording. This is a popular move in the Grateful Dead/Jerry Garcia tone chasers world for getting what Garcia used from 70 or so until 1991. Several of the people that used to make these and resell them have stopped! So i figure it cant be that hard.
I can deal with the soldering, schematics (to a degree) and tubes i believe. What I am not really any good at is designing a PCB correctly. Or even finding the parts on the Easy EDA web tool. Looking for tube sockets, anything like that or even a 1/4 in input has been quite a challenge!
Who's had good luck with a specific software/web tool to do these sorts of PCB's with tubes and all the audio type connections that we prefer? Thanks!
I can deal with the soldering, schematics (to a degree) and tubes i believe. What I am not really any good at is designing a PCB correctly. Or even finding the parts on the Easy EDA web tool. Looking for tube sockets, anything like that or even a 1/4 in input has been quite a challenge!
Who's had good luck with a specific software/web tool to do these sorts of PCB's with tubes and all the audio type connections that we prefer? Thanks!
That.https://sep.yimg.com/ca/I/alembic_2229_20991
If at all possible, direct mount to chassis pots, jacks, switches, etc. and put components only on PCB.
Or do what Leo did: clone one of his eyeletted boards 🙂
http://www.prowessamplifiers.com/schematics/fender/twin_reverb_ab763_layout.pdf
clone only the normal channel.
In fact, the Alembic preamp Jerry Garcia used had two of those in a single rack unit:
If at all possible, direct mount to chassis pots, jacks, switches, etc. and put components only on PCB.
Or do what Leo did: clone one of his eyeletted boards 🙂
http://www.prowessamplifiers.com/schematics/fender/twin_reverb_ab763_layout.pdf
clone only the normal channel.
In fact, the Alembic preamp Jerry Garcia used had two of those in a single rack unit:
I use DIY Layout Creator for guitar amp designs:
DIYLC Latest Version
I can make PCBs using turrets or eyelets and connect to flying lead components as with a Fender circuit for example.
That software is still actively being improved / fixed and is free.
DIYLC Latest Version
I can make PCBs using turrets or eyelets and connect to flying lead components as with a Fender circuit for example.
That software is still actively being improved / fixed and is free.
It would be really interesting to use that layout creator to make baseline layouts for drop-in turret board replacement PCBs that you then use as a baseline to transfer over to easyEDA, that way you populate a board and then just load up the chassis with jacks. Would make circuit swaps and beginner builds really easy- they'd be trivial to put together. Get the pads on the PCBs sized right to take turrets fit right in.
Then make your own versions of stuff like this-
https://tubedepot.com/products/5e1-...l43NwNGPlcBadLqsBIHiJC1hapDD2_sxoC-uYQAvD_BwE
Then make your own versions of stuff like this-
https://tubedepot.com/products/5e1-...l43NwNGPlcBadLqsBIHiJC1hapDD2_sxoC-uYQAvD_BwE
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Ki-cad is very capable but has a learning curve. I know people who design with it for a living.
In general most PCB packages allow you to (relatively) easily design your own parts footprints.
Even IF they include tube sockets, multi section pushbutton switches, a couple jacks ... you will always use some locally available product with its own quirky size, so ....
Usually not much more difficult than placing some array of suitable pads at convenient places and drawing a silkscreen image around it to assist in placing, then you "group" those elements together, give it a name (such as Noval-2) and add it to a parts Library.
Even IF they include tube sockets, multi section pushbutton switches, a couple jacks ... you will always use some locally available product with its own quirky size, so ....
Usually not much more difficult than placing some array of suitable pads at convenient places and drawing a silkscreen image around it to assist in placing, then you "group" those elements together, give it a name (such as Noval-2) and add it to a parts Library.
What is that, seven turrets? Hardly worth making a PCB, let alone the phenolic/epoxy-tainted sound of PCBs.
EDIT: I see I snipped a couple cathode networks. Ten turrets. 10 copper tacks in cigar-box wood.
Thanks for the rec's. I started making the schematic pre mods. But I cannot find the correct transformer layouts. I guess i can worry about power later. But when I ran a quick test I guess according to the schematic checker, i dont even have any power here. HA. Is there a way to layout the actual power and have the voltages change within the circuit on the schematic or does everything have to be written out? Thanks!
These are rad! Vibrato channel. Normal channel wasnt used. Garcia didn't use these. He used his chopped Silverface twin with the original Blackface as a backup.That.https://sep.yimg.com/ca/I/alembic_2229_20991
If at all possible, direct mount to chassis pots, jacks, switches, etc. and put components only on PCB.
Or do what Leo did: clone one of his eyeletted boards 🙂
http://www.prowessamplifiers.com/schematics/fender/twin_reverb_ab763_layout.pdf
clone only the normal channel.
In fact, the Alembic preamp Jerry Garcia used had two of those in a single rack unit:
I think Phil used these Alembics though and Bob.
In the early 1990's until his death Garcia used one of these Groove Tubes Trio's which was modified but still through his McIntosh and JBL speakers!
Attachments
Treble and volume pots connected wrong.
Voltages? Are you doing PCB layout or circuit design? While the both can be found together in some (usually very expensive) software, I suspect if you copy Leo's values the voltages will find themselves.
Maybe so but this thread is not "what Jerry Garcia used" but how to make a PCB for housing
which is exactly what Alembic F2B has inside (two such channels):
and I suggested "why make a PCB at all?" since it nicely fits in a very simple eyeletted board (what Leo used), simpler than turrets.
Neither could Alembic 😉 , it´s hard to wind hair thin wire (actually thinner, go figure) for thousands of turns for high voltages without going veeeeryyyy slow and even more, still having lots of breakages. A true PITA.
Any transformer winder around here will confirm that.
But look at what they did: used a voltage doubler, so half the turns, twice the wire section ... a win-win situation.
Start searching for a similar transformer yourself.
In fact a simple cheap 1:1 120V-120V isolation transformer will take care of he HV rails, you still need 6.3V winding: if lucky in the same HV transformer as shown in schematic, if not care of a second 6.3V filament transformer ... easy peasy.
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