trinityamps.com

Hi everyone,

I posted this quesion already in another thread (viewtopic.php?t=1818), but I thought it may be good to start one myself.

This will be my first amp kit build, so expect more (dumb) questions...

This is what I posted:

....Right now I have the control pot in the second speaker jack hole, and plan on mounting the vrm board at the hole for the power ground. My chassis has an extra hole near the power ground more towards the power tubes. This Is where I will relocate the power ground.

I haven´t wired it up yet, as I am not sure if the pot and board will be too close to the heater wires, and if the leads from the vrm board to the pot will be too long.

I have routed the heater wires from the pilot light along the right side of the power transformer, down to the first power tube; and from there according the layout along the edge of the chassis from tube to tube.

Any thoughts on how to make this work as best as possible are greatly appreciated.....






Today I thought it might be a good idea to drill a hole in the backplate off the cabinet, right opposite where the vrm board is mounted, and place the control pot there.

This way the leads going to the pot will be the shortest, and the pot will not be so near to the heater wires as before.

I would love to hear some comments on this, since the cabinet Stephen sold me is spectacular, and I don't want to put any holes in it before I'm sure that itt will work.

Thanks

I'll wait to hear other comments, but you can replace the standby switch with the VRM control if you want.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks Stephen,

I thought about that too, but I get nervous when things I use are not labeled correctly.... Kind of neurotic, I know. I can´t help it, that´s how I´ve been trained

Boom, as Stephen suggests, the standby position is a good place for the VRM pot on a Deluxe. That's where I put mine. I don't think you'd have any confusion with that placement, if you use a switched (on-off) pot, because it then becomes obvious what control you have there - there is no other way to power up the amp (and the power on lamp indicates "on" as well). There is room on the floor of the Deluxe chassis, at the PT end of the board, to place the VRM itself, and the wiring in that location is fairly short and simple (both the B+ to the board and to the pot).

Steve posted his rationale for locating his VRM here viewtopic.php?t=1818

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks guys,

I guess I´ll opt for the standby switch location after all...

Of course I wouldn´t really be confused or anything, it´s just that I don´t like it when something isn´t labeled correctly. But then again, as you say, when you use a switched pot it becomes a standby switch of sorts again.

So a 1/4 or 1/2 watt rated 1M pot will do ? Is there a reason why you (Stephen) suggest a lin pot ? I can see why HarmonyOfTheSpheres likes the log pot. It would feel more like a volume control, I guess.

Now to find someone in Europe that has those pots. The only one I found was Mouser, but then again....20 euros shipping costs for one pot ?!

Stephen, I would like to use the same chickenhead knob as you supplied with the kit. Are those easy to find ? Or can I buy one from you ?

Thanks again for you insights ! (All of you)

Hey Boom, sorry, I inadvertently misled you. I installed the VRM on my Deluxe in the place of the ON/OFF toggle, not in place of the Standby toggle. My standby is still intact in the circuit.

So, with the switched pot, the first bit of travel on the pot turns on the power (leave the standby engaged until the amp warms up, then standby off). The pot travel after that increases the VRM output, effectively increasing amp volume without changing the tonal/saturation settings of the two volume pots.

If you didn't find circuit diagrams or a layout of the wiring for this already, email me privately and I'll send you my layout. Sorry I don't remember where I purchased my pot, but it was not expensive.

Thanks everybody.

I've started this build, and decided to take up HarmonyoftheSpheres's advice. I'll replace the power switch with a switched pot.

I hope to post some progress udates soon.

Boom, I just wanted to mention that you should make sure that switch section of the switched pot you select is rated properly for this application. I see the Deluxe is fused at 2 amps, probably a slow blow type fuse to allow for the "kick" of the transformer turning on. If I were me (which I am) I would spec the switch for at least twice that current if possible to be on the safe side. I see a lot of those rotary type switched pots are rated at 2 amps which may not hold up over time if there is arcing. A cap across this switch probably wouldn't hurt either, but I'll let the experts chime in on that one

Joe G

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Hi Joe,

thanks for the tip. I can´t seem to find any switched pots with a 3 or 4 amp rating, but I´ve bought this A1M Alpha switched pot which is supposedly use as an on/off switch for the Champ. I would have preferred the B1M, but the only store that has that one seems to be mouser. (1 pot shipping to the netherlands would be very expensive)

I tried to get the specs for this pot, but even on Mouser and Alpha´s website I had no luck finding the switch amp rating.

I guess we´ll find out when I plug it in. (220V here)

I finally finished my install last night.

I rejected using a switched pot, which limited my options a bit. In the end, I decided on a hidden fuse holder.

I drilled a new hole for the fuse holder on the end of the chassis, and moved the standby switch into the old fuse location. The new power supply control layout is as follows: power switch, standby, VRM and pilot light. I think it looks tidy, and the wiring runs are nice and short.

Photos are here:

http://www.facebook.com/album.php?aid=1 ... 53764e3a3c

Pardon my sloppy wiring. I was pretty anal about the original build, but this time, I was rushing to get the thing mounted, so I could enjoy it!

Well, that's a new way to mount in the Deluxe. Hope it worked out foryou.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Seems to be working great. Of course, the downside is that I would have to pull four screws and the back panel, should I need to replace the fuse...

Actually, you can also replace the standby switch with the VRM control. You can then turn the VRM to min, turn on the amp, and after a suitable period of time, turn the VRM to where you want it.

So you actually get a variable standby.

the other option is to replace one of the output jacks with the VRM control. Just twist the wires to the VRM board. You could also mount the VRM module on the outside of the chassis & feed the wires through if there was too much noise introduced this way, but I think it would be OK.

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I like the idea, but on my Deluxe there isn't enough room around the standby switch to rotate a chicken head knob, as the cab is in the way. Any suggestions for a suitable alternative knob?

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Just about any bakelite knob that doesn't have an aluminum insert in the top, will fit in nicely with chickenhead knobs.

Old-style Jazz Bass knobs look pretty cool. They're round, with an easy-to-see white pointer line on them, and they tend to be cheaper than radio knobs.

Ham radio gear can be a feast of old-timey looking knobs, and those guys love to trade.

Toronto used to be a treasure trove of surplus stores. I got a ton of bakelite knobs for cheap from one of them (can't remember the name), that sold a lot of old gear as setpieces to the movie industry.