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June 02, 2023, 10:40:07 AM

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Sunn Beta PCB

Started by Tassieviking, November 05, 2021, 10:51:07 AM

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Tassieviking

After thinking about it for a long while, I finally decided to create a Sun Beta PCB for myself and order some.
I was trying to work out the correct dimensions between the pots but it was really hard, until Fishheadjoe posted some pics for me of his head on the TalkBass forum.
The spacing is most likely not spot on but it is as close as I can get unless I have a original PCB to work from.
I made the PCB up in Kicad, and I added some of my own mods because I like them.
All the 2.2uF NP Electro capacitors ( originally 2uF ) can be used or there is space for WIMA MKS type at 5mm pitch and up to 7.2mm x 7.2mm body in the same place.
I made it for both Bass and Lead, just remove the pots you don't need, Lead - remove the Bass Level pots and Bass Master pot, Bass  - remove the reverb pots and Lead Level and Master.
I bet some who look at the pics will think it has some funny spider pot on there instead of either a Lead Reverb or Bass Level in the same place.
I also added a different power supply plug where the power goes through a 7815 and 7915 regulator in case it is needed to make +-15V
Just delete C1 D1 U1 C2 D2 U2 and the 18-35V supply plug if you already have a +-15V supply handy.
I also made a different footprint for the supply caps C156, C157, C1, C2,  originally C156 and C157 was 10uF 25V, the footprint will fit caps up to 10mm with 2.5mm or 5mm pitch so you can go for a higher value if you want.
The foot Switch circuit is one I got from DiscoVlad on the FSB forum, he used it and said it works fine. Original chips used by Sunn are too hard to find.
This PCB is not tested to see if it works so use at your own risk
I have ordered 5 PCB's from JLCPCB and am waiting for them to arrive, I will post if I have any trouble with them, Its my Xmas present for myself.
I am going to stick it in a 2U or 3U ( front send / return jacks ) rack mount case for myself and my daughter, Lead for me and Lead and Bass for my daughter.
I made all the connectors Molex KK396 type as Tayda carries them and I get most of my components from them when its for me or my daughter, I might just solder wires straight to the PCB though instead of using connectors.
There are no stupid questions.
There are only stupid mistakes.

Loudthud


Tassieviking

I remember reading that post on the Sunn forum a long time ago, thanks for reminding me LoudThud
There are no stupid questions.
There are only stupid mistakes.

Jimladladlooklike

Hey Tassieviking. Awesome work on this, I'm jealous of your PCB design skills!

I was just wondering if you'd made any progress with the building process as I'd be really interested to have a go at this project myself. I've built two tube amps (currently on my third!) but I'm a big fan of SS stuff and would like to branch out.

Cheers.

Tassieviking

Unfortunately I haven't completed this one yet, my dad got really sick early last year so I flew up to where he lived and stayed with him for quiet some time.
And then it was the funeral, cleaning up his house and sorting out what I wanted to keep etc.
It kept me occupied for 6-7 months and then I didn't get back to the Sunn Beta project.
I did finish one of the Marshall 12 watt amps I made a PCB for though.

I remember I was tweaking the resistor values in the channel switching circuit so it would work better and only use 1/4 watt resistors, I don't think I had a lot left to do before the PCB was finished for the BASS version I was building.

I can not see any reason why it will not work, I left the Gerber files I sent to JLCPCB to get the PCB's made in the first post

Thanks for reminding me, I will drag it out and get into it again very soon.
Are you interested in the Lead version or the Bass version ?

There are no stupid questions.
There are only stupid mistakes.

Jimladladlooklike

Sorry to hear of your Dad's passing. I know how difficult and derailing such things can be. Hope you're coping alright nowadays.

The 12 Watt Marshall sounds cool. Would love to hear that if theres a link you can share?

I'm interested in the Lead version. In order to get PCBs made I'm presuming I just send the Gerber files to whichever manufacturer I choose? Apologies, this is my first time ordering PCBs from files.

Thanks

Tassieviking

I don't have any audio files so you can hear the 12w Marshall amp I made.
The PCB I made up is made so you can build all 5 versions I found schematics for, you just have to use the right components from the BOM.
I also changed the power amplifier so it can be made into a 30watt amp as well.
You can pick Lead, Reverb,Bass etc.
Link: https://www.ssguitar.com/index.php?topic=5164.0

I was never a good player and I have bad arthritis in my hands now so I can't be bothered to make any sound clips.
But I love to make up PCB's and build stuff when I can.

To get PCB's made you just have to upload the Gerber to the PCB manufacturer, I personally have only used JLCPCB as they are a good price.
The one problem with JLCPCB is that you have to order 5 PCB's minimum of the same type, but it still works out cheaper then buying 1 PCB from most online shops so I just end up with spares.
The shipping can get very expensive with JLCPCB as well, but if you pick the cheapest postage they are ok, and still fairly fast (2-3 weeks).




There are no stupid questions.
There are only stupid mistakes.

joecool85

Quote from: Tassieviking on April 03, 2023, 04:53:29 PMI don't have any audio files so you can hear the 12w Marshall amp I made.
The PCB I made up is made so you can build all 5 versions I found schematics for, you just have to use the right components from the BOM.
I also changed the power amplifier so it can be made into a 30watt amp as well.
You can pick Lead, Reverb,Bass etc.
Link: https://www.ssguitar.com/index.php?topic=5164.0

I was never a good player and I have bad arthritis in my hands now so I can't be bothered to make any sound clips.
But I love to make up PCB's and build stuff when I can.

To get PCB's made you just have to upload the Gerber to the PCB manufacturer, I personally have only used JLCPCB as they are a good price.
The one problem with JLCPCB is that you have to order 5 PCB's minimum of the same type, but it still works out cheaper then buying 1 PCB from most online shops so I just end up with spares.
The shipping can get very expensive with JLCPCB as well, but if you pick the cheapest postage they are ok, and still fairly fast (2-3 weeks).






I recommend you try OSHPark.  They aren't as cheap as overseas places, but still very reasonable.  Good example, I just did a mini board that is basically a strip with 6 connections points and two mounting holes.  A set of 3 boards cost me $1.50 shipped.
Life is what you make it.
Still rockin' the Dean Markley K-20X
thatraymond.com

Jimladladlooklike

That's fair enough!

I ordered 5 boards (min order) from PCBgogo about a week ago, they should be arriving soon. All being well I should have the time to start this project properly later on this year. I will post here with any updates.

Thanks again

Tassieviking

#9
Great,
If you have problems finding the B1M dual gang pots you can get them from Tayda, that's where I get most of my parts from
https://www.taydaelectronics.com/pb-1m-ohm-linear-dual-taper-potentiometer-pc-mount-round-shaft-l.html

I have read that changing the level and master pots to A100k instead of B100k makes it easier to control the volume, also one of the tone pots can be improved by going to C100k, but I can't remember which one right now.(Treble ?)
I also changed the values of the resistors in the foot pedal circuit to higher values and 1/4 watt but I haven't proven that yet except on a breadboard.

The Sunn Beta has a strange plug for the foot pedal, I was going to use a 4 pin GX12 or GX16, but any 4 pin plug will do.
https://www.taydaelectronics.com/connectors-sockets/midi-connectors/4-pins-male-circular-connector-12mm-gx12.html
https://www.taydaelectronics.com/connectors-sockets/midi-connectors/4-pins-male-circular-connector-gx16.html
Cheers
Mick
There are no stupid questions.
There are only stupid mistakes.

Jimladladlooklike

Great, thank you for all of that info. I'm sure I can scour some more forums and find out some other peoples recommendations regarding those pot values.

Now to figure out what chassis/transformers to buy

Tassieviking

I think I was going to put it in a 2U rack case originally, but I think it would be better in something like a Hammond 1441-33 case (17x4x10).

You also have to consider what Power amplifier you are going to use with the pre-amp, that will determine the transformer you need.

If you are looking for the font for the writing on the front panel (c-mos) I think the font "FontsFree-Net-bitwise.ttf" comes close.

here are some pics of a front panel PCB I was working on, I sometimes use a PCB as a fascia on my home jobs.
I have made the front for Lead and the back for Bass, on the Bass I labeled the reverb pot as comp as I was going to add a 1 knob compressor to it separately and place a pot in the reverb position.
There are no stupid questions.
There are only stupid mistakes.