Jump to content

kgst


kevin gilmore

Recommended Posts

Looks very good - only annoying thing is that I already ordered a couple of boards of the older version and the KGST amps  8) I can see the amp board has been upgraded to v0.51 as well, can I ask what was changed?

 

Oh, one minor error in the silkscreen by the way - one of the big caps is marked as 50V, not 500V.

 

 

//UFN

Link to comment
Share on other sites

Group buy announcement!

 

See why I said there would be a short pause?  As soon as these two gentlemen commit to a final for production for the group I will do the group buy.  Hopefully in the next few days.

 

I will pm all people who have put their names down for confirmation and payment.

 

The total requests for amps was around 80 boards and PS 50.

  • Like 1
Link to comment
Share on other sites

Just so it is clear, this PSU is exactly the same as the other one I did.  Kevin just wanted to move it to the same layout architecture we use for all other boards so we drew it. 

 

Ohh and everything changes for us.  There is nothing set in stone so constant improvements.  I've lost count of how many revisions there are of the KGSSHV boards, at least 60 minor ones and almost 20 major ones. 

Link to comment
Share on other sites

Group buy pcbs;

 

I have just pm'ed everyone who asked for boards.

 

If anyone else wants KGST amp or PS boards - shout now because the order will go in a few days.

 

Confirm the number you want and I'll tell you how much to paypal me.

 

 

Cheers

Is there still a possibility tot order a set of boards?
Link to comment
Share on other sites

Since this will me my first amp built with tubes, I have two questions.

 

1. Which tube sockets should I get?  Are these the right ones and ok? http://www.ebay.com/itm/4pcs-GOLD-9pin-PCB-Ceramic-vacuum-tube-sockets-valve-base-12AX7-12AU7-ECC83-6N11-/231285734941?pt=Vintage_Electronics_R2&hash=item35d9b43e1d

 

2. Which 6s4a tubes should I get. Can I use other types of tubes? If I understand correctly I need at least matched pairs, better matched quads. Which tubes are a good choice for the KGST?

 

Help is really appreciated, thanks!

Edited by insanity
Link to comment
Share on other sites

That socket should fit but these are the most common ones and what I used/designed for:

 

http://www.ebay.com/itm/10-9pin-Ceramic-Tube-Socket-PCB-B9A-6DJ8-12AX7-ECC83-ECC82-12AU7-6922-6N11-Valve-/131242710847?pt=Vintage_Electronics_R2&hash=item1e8eacd73f

 

Available from pretty much everywhere.  The board also takes the teflon sockets such as this one:

 

http://www.ebay.com/itm/NEXUS-MUSIC-Premium-9-PIN-9P-Gold-Plated-Teflon-Tube-Socket-12AU7-ECC83-2PCS-/181469359862?pt=Vintage_Electronics_R2&hash=item2a406aaef6

 

For tubes its the 6S4A that works and nothing else.  There are really no tubes like it though some are similar but with incompatible pinouts.  I got some 6973's on Friday which are a beam pentode and in current production which might work on a modified ST board triode strapped.  As soon as I get my new board then I'll try it. 

 

As for matching, you need matched pairs for each channel but a matched quad doesn't hurt.  Matched build is also what I'd go for so all of them RCA or GE, the actual branding doesn't matter. 

 

A note about the voltage though.  After running my tiny 400V for some time now I would advice people stick to +/350V rail voltages as 400V runs too hot for comfort.  It's the first amp I've ever had to use a fully vented cover for... 

Link to comment
Share on other sites

Thank you for your reply. 

 

If I go for 350V rail voltage, what are the transformer specs I need? 

 

0-6.3V 1.4A (2x)

-18-0-18V  ??A

300v? ??A

 

I think the Zenerstring would need to be 150 100 100V, right?

Anything else that needs to be adapted? What about the bias voltage?

That socket should fit but these are the most common ones and what I used/designed for:

 

http://www.ebay.com/itm/10-9pin-Ceramic-Tube-Socket-PCB-B9A-6DJ8-12AX7-ECC83-ECC82-12AU7-6922-6N11-Valve-/131242710847?pt=Vintage_Electronics_R2&hash=item1e8eacd73f

 

Available from pretty much everywhere.  The board also takes the teflon sockets such as this one:

 

http://www.ebay.com/itm/NEXUS-MUSIC-Premium-9-PIN-9P-Gold-Plated-Teflon-Tube-Socket-12AU7-ECC83-2PCS-/181469359862?pt=Vintage_Electronics_R2&hash=item2a406aaef6

 

For tubes its the 6S4A that works and nothing else.  There are really no tubes like it though some are similar but with incompatible pinouts.  I got some 6973's on Friday which are a beam pentode and in current production which might work on a modified ST board triode strapped.  As soon as I get my new board then I'll try it. 

 

As for matching, you need matched pairs for each channel but a matched quad doesn't hurt.  Matched build is also what I'd go for so all of them RCA or GE, the actual branding doesn't matter. 

 

A note about the voltage though.  After running my tiny 400V for some time now I would advice people stick to +/350V rail voltages as 400V runs too hot for comfort.  It's the first amp I've ever had to use a fully vented cover for... 

Edited by insanity
Link to comment
Share on other sites

I believe it should be 280V and around 140-150mA, so complete min. specs for a custom wound would be:

 

Pri: Whatever voltage(s) you need, power = 120VA or higher.

Sec. 1: 280V/min. 40VA

Sec. 2: 280V/min. 40VA

Sec. 3: 15V/min. 10VA

Sec. 4: 15V/min. 10VA

Sec. 5: 6.3V/min. 10VA

Sec. 6: 6.3V/min. 10VA

 

You can go higher power if you want of course. The 15V windings can be higher voltage (16-18V) if you want but it should not be necessary given the dropout voltage of the LM78xx/79xx regulators. It can also be 15-0-15 center-tapped instead of two discrete secondaries if you prefer.

 

//UFN

Link to comment
Share on other sites

Since this will me my first amp built with tubes, I have two questions.

1. Which tube sockets should I get? Are these the right ones and ok? http://www.ebay.com/itm/4pcs-GOLD-9pin-PCB-Ceramic-vacuum-tube-sockets-valve-base-12AX7-12AU7-ECC83-6N11-/231285734941?pt=Vintage_Electronics_R2&hash=item35d9b43e1d

2. Which 6s4a tubes should I get. Can I use other types of tubes? If I understand correctly I need at least matched pairs, better matched quads. Which tubes are a good choice for the KGST?

Help is really appreciated, thanks!

If it helps at all, I was able to get a matched quad of 6s4a for $32 from http://vacuumtubes.net. They seem to be one of the few places with a large enough stock to do any matching

Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

Are there any non-custom transformers that would work, maybe something from Antek? Or is custom the way to go?

Also, is there any reason not to mount the tubes on top of the amp with chassis mount sockets (aside from the extra work)?

Sent from my iPhone using Tapatalk

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.