Matchless Lightning build

[M Fowler]

Here is a Matchless Lightning I built this week. Will make faceplate and cabinet soon.

Master volume works well at mid to high volume but fizzy at low volume.
The Master volume pot cuts out at 75% so that will be replaced.

Cheap Weber chassis, Heyboer 18w Marshall tranny set and Hammond 158m choke.

Mark

[David Root]

More nice work! Couple of comments if I may.

I noticed those Illinois caps (IC). Are they OK now? two or three years ago they were not so good, people had trouble with them.

I have heard (not tried in Marshalls myself) that the ARS can caps from California are the best for Marshall circuits. Lot of people use JJ incl. myself. Just curious. I have a '77 50W MV that will need caps pretty soon.

I also noticed you tie your iron down with Fender washers. Have you had trouble with it moving about?

[Andy Le Blanc]

Those caps have the highest max RMS ripple current rating at their price point.

looks good but why the fender dress?

This schematic? I heard a discussion about the choice to use parallel 12ax7
current vs voltage , that'll sound nice.

If your gonna replace the master put in a push pull switch, pull to disable.

[Gee]

Nice build. A newborn Lightning is a thing to celebrate.

[M Fowler]

Thanks guys I used the fender washers because the ones I had were too small and these were handy. Its funny because I never use fender washers and I had read that for tubes down amps people like to use them for extra protection from the heavy transformers. So I looked in my parts drawer and saw them and said OK they're big but I'll use them this time. See what happened, two posts on the fenders

The caps, well I have never had any problems with IC or can caps and I keep hearing stories about both.

Andy I think I have a dual 1MA pot I can put in there thanks.

[tribi9]

That looks really nice Mark. I bet its going to sound awesome once you're done tweaking it. (It probably already does now)

[Andy Le Blanc]

Whats your plan for the faceplate? Will you be able to fabricate in house?

[Bear]

Your OT is 8k? Have you tried an intentional mismatch to check out the 4k sound? You may prefer it -- that's one of the quirks of the originals.

If you ditch the MV, a Cut control will sometimes really suit these amps, which makes sense given their heritage.

[M Fowler]

tribi9, I will be working on it this week and decide on what direction to go next with it such as Master volume dual pot or not or cut control which I like.

Andy, I usually go with FrontPanelExpress and have not been successful in making my own front panels. I have been incontact with a local vinyl vendor and have thought going that route as well.

Bear, I had read about that with Gee's threads and so far have not gone that direction but it could be something to consider. I do like a cut control as you mentioned so that is something I will try besides Andy's mention of the dual MV pot to turn off the Master. I have empty holes on the front so I could install some more pots and switches.

[Andy Le Blanc]

Its not really a mismatch if its design. Was the OPT in Bears reference use to increase or decrease
the reflected impedance that the tubes see?

[M Fowler]

Its not really a mismatch if its design. Was the OPT in Bears reference use to increase or decrease
the reflected impedance that the tubes see?

Andy I can't see the difference if I go with 4k and have to change impedence or stay with the 8k at 4 or 8 ohm. The turns ratio is the same depending on the impedence load right?

Mark

[Structo]

Nice Mark.

Do these lean towards the Vox tone?

Did you use the Schematic Heaven schematic?

[M Fowler]

Thanks Tom, I have about three different Lightning schematics/layouts and what I did was use part of Ceriatone, part of Trinty 15, and Dockery amps. There is very little difference other than six filter caps on Trinty/Dockery and 5 on Ceriatone.

I used Turretboards.com 18w Heyboer tranny set and Hammond 158m choke. Ken Watt's 18w tranny set uses standup PT which I like so my last three 18w builds have used that set. I think it leans toward Marshall to my ears but I am not messing around yet.

I have been busy with my Swamper amp get it ready to gig with.

[Gee]

Andy I can't see the difference if I go with 4k and have to change impedence or stay with the 8k at 4 or 8 ohm. The turns ratio is the same depending on the impedence load right?

On my Spitfire and Lightning/Royale builds I switch my 8ohm speaker to the 16ohm setting to get the 4K primary. However, so far I prefer the normal 8K, i.e. 8ohm output to 8ohm speaker. There is is slightly more distortion and less output when using the 4K. The drop in volume when going from 8K to 4K may be misleading though. Your ears can get tricked into thinking the sound is not so good when the volume drops.

[Andy Le Blanc]

The transformer X drops when you do it that way, but I remember the DCR
of the transformer stays the same. Going the other way the DCR is lower
relative to the Impedance that the tubes see.