Search found 158 matches

by Heikki
Thu Jul 03, 2025 7:21 am
Forum: Transformerless VariMu
Topic: Instructions, Schematics & Specs (NEW VERSION)
Replies: 7
Views: 335

Re: Instructions, Schematics & Specs (NEW VERSION)

This is the type of tube socket I recommend using.
https://www.tubetown.net/ttstore/en/soc ... leads.html

If gain reduction LEDs light up too early change R150 & R151 on the sidechain board to 12k or 15k.
by Heikki
Fri Jun 20, 2025 1:24 pm
Forum: Transformerless VariMu
Topic: Instructions, Schematics & Specs (NEW VERSION)
Replies: 7
Views: 335

Re: Instructions, Schematics & Specs (NEW VERSION)

Use heatsinks or mount regulators U1 & U2 on DC-DC PS board to chassis!
valmis3.jpg
valmis4.jpg
by Heikki
Fri Jun 20, 2025 1:21 pm
Forum: Transformerless VariMu
Topic: Instructions, Schematics & Specs (NEW VERSION)
Replies: 7
Views: 335

Re: Instructions, Schematics & Specs (NEW VERSION)

Mount the sidechain board to front panel.
front2.jpg
front1.jpg
by Heikki
Fri Jun 20, 2025 1:16 pm
Forum: Transformerless VariMu
Topic: Instructions, Schematics & Specs (NEW VERSION)
Replies: 7
Views: 335

Re: Instructions, Schematics & Specs (NEW VERSION)

Assembly and wiring.

Layout
https://ghr.fi/varimu2/schematics/layout.pdf

Use plastic standoffs under PS board
PSplasticstandoff.jpg
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boardsmainpsmeter.jpg
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kasauskuva1.jpg
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by Heikki
Fri Jun 20, 2025 1:12 pm
Forum: Transformerless VariMu
Topic: Instructions, Schematics & Specs (NEW VERSION)
Replies: 7
Views: 335

Re: Instructions, Schematics & Specs (NEW VERSION)

Mount the tube sockets with standoffs before soldering!
standoffs.jpg
kompurakanta2.gif
by Heikki
Fri Jun 20, 2025 1:05 pm
Forum: Transformerless VariMu
Topic: Instructions, Schematics & Specs (NEW VERSION)
Replies: 7
Views: 335

Re: Instructions, Schematics & Specs (NEW VERSION)

Before populating the boards use main board, PS board & meter board to mark mounting holes to the chassis.

Populated boards
main1.jpg
-

U1 on power supply board should be mounted to chassis. U2 can be mounted to chassis or should have a heat sink.
psandmeter.jpg
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sichainfull.jpg ...
by Heikki
Fri Jun 20, 2025 12:57 pm
Forum: Transformerless VariMu
Topic: Instructions, Schematics & Specs (NEW VERSION)
Replies: 7
Views: 335

Instructions, Schematics & Specs (NEW VERSION)

If you want to buy boards send me a PM or email

Schematics & Layout
https://ghr.fi/varimu2/schematics/

Calibration instructions
https://ghr.fi/varimu2/specs.pdf

Front Panel Designer file
https://ghr.fi/varimu2/varimu3Ughrrotarybigboard.fpd

BOM
https://ghr.fi/varimu2/bom/
by Heikki
Fri Jun 20, 2025 12:49 pm
Forum: Transformerless VariMu
Topic: New version coming soon!
Replies: 23
Views: 27924

Re: New version coming soon!

Specs and calibration instructions
https://ghr.fi/varimu2/specs.pdf
by Heikki
Fri Jun 20, 2025 12:46 pm
Forum: Transformerless VariMu
Topic: New version coming soon!
Replies: 23
Views: 27924

Re: New version coming soon!

Meter board had inputs in one opamp crossed. Pictures with new working meter board.
valmis4.jpg
valmis3.jpg