K60 - switching remotely and VVR

[deuce42]

Hi guys

I would like to switch my fast/gradual with a footswitch but didn't seem to get much luck from Hall amplification.

I'm wondering if the following from Kevin O'Conner would do the trick although I am wondering whether it could handle the high power that may normally go through the Asteroid's fast/gradual switch:

http://www.londonpower.com/all-kits/ele ... -relay-kit


On another note, I read that Hall Amplification's VVR is limited to amps up to 50w. I see on ampgarage here that some guys have put a VVR circuit into a K60. Can the VVR handle the extra watts for a k60???

Thanks guys

[Colossal]

There's no need to put DC on the relay at all. Route the inputs from the split load to the relay open and closed via a coupling cap. The relay common then becomes the output to the next stage. You only need one common, not two as shown in the diagram (which is for a switch version)...basically two in, one out...either Fast or Gradual.

Like this...

[deuce42]

Ok so the addition of the 2n cap and the relay. How is the relay then powered? Just via its own source frm the HT tap or 6.3v?

[Colossal]

Ok so the addition of the 2n cap and the relay. How is the relay then powered? Just via its own source frm the HT tap or 6.3v?

Yep, relay needs a power source. 6.3VAC is good. Rectify, filter heavily and drop to 5VDC (assuming of course your relay is 5VDC).

[pablogt]

Attached is the schematic of my K50 with VVR and footswitchable speed.

P.

[passfan]

Halls VVR is a resounding no on a Komet 60. Try something from London Power

[pablogt]

I used London Power's SB1 which is no longer produced, I think it has been substituted by SV1. Works fine. I think Dana's VVR would work fine too if used to regulate just the PA section.

P.

[deuce42]

Screen Shot 2019-03-14 at 11.08.06.png

There's no need to put DC on the relay at all. Route the inputs from the split load to the relay open and closed via a coupling cap. The relay common then becomes the output to the next stage. You only need one common, not two as shown in the diagram (which is for a switch version)...basically two in, one out...either Fast or Gradual.

Like this...

hi guys, I'm sorry to dig up an old thread, but hoping for some clues.

1) In the diagram attached here, I understand the 2n coupling cap for the switching relay, but what is 150k resistor? Is it some sort of buffer coming off the common switch?

2) I've also got a horrific feedback squeal in fast mode with the amp volume past about 6. I cannot work out where the problem is but am guessing it's somewhere around this remote relay switch. I used the Colossal switching relay board from a few years ago. Works really well. The squeal is possibly some other issue not in the board or how/where I've routed the wires to the board?

3) Also, looking at the K60 schematic and the above scheme, in addition to the 150k resistor, are the circuits slightly different? ie the 0.1uf cap goes to a 220k/330k then to pin 7 of V2b on the K60 schem. I'm a bit confused.

Thanks for any help in advance!

[Tony Bones]

1) Without the 150k, what would the DC grid bias be?

2) Swap the primary wires on the OT.

3) Except for the fact that they're both fast/gradual switches, the two circuits are completely different.

[deuce42]

ok thanks Tony bones.

I think I'm almost there. Just one last thing I realise and then I'm a happy build user and grateful to everyone here for all their help.

There is a "Bass mod", "Cameron Mod", "Pete Thorn mod", insert whatever name its otherwise called.... and please excuse me if I've not credited anyone here who did devise it. I understand its the 100n cap in the gradual switching circuit I posted above. Given this diagram adds a relay board switch and has another cap (2n), can someone tell me what value it could/should be changed to stop the mushy bass response?? Does having both the 100n and 2n caps already in the switching circuit change things? This is my last buggy issue!

Cheers guys and thanks

[deuce42]

Hi guys, any advice regarding the cap value and where to insert it for this mod would be so appreciated.

As I've used the switching circuit for the gradual/fast, I just can't seem to determine what cap would be changed to do this mod?

Cheers and thanks
deuce

[Colossal]

Hi guys, any advice regarding the cap value and where to insert it for this mod would be so appreciated.

As I've used the switching circuit for the gradual/fast, I just can't seem to determine what cap would be changed to do this mod?

Cheers and thanks
deuce

Deuce, if memory serves, I believe the fast/gradual mod you are speaking of is lowering the 0.1uF to 0.022uF. That's it. There are the so-called Mark Knoplfer mods that change a few other values in the K60. Search the foum for those key words, this has definitely been discussed before.

[deuce42]

Oj thanks Colossal - I strangely just had this idea things would be different if it was using the switching boards of yours. I'll swap out the 100n for a smaller cap now.

Thanks again!

[Colossal]

Right on! Let us know how you do.