Build, well, components buy for 124-based ODS

[DonMoose]

As mentioned in the big caps thread, I'm gearing up to start a build on a 124 + built-in d'lator with a precision power supply into a PV MX Flite chassis on an abgamps boardset.

Tight, but manageable because both transformers are stand-ups. The preamp tube order, left-to-right, is Dlator, V1, V2, PI. That diagonal offset should put the tagstrip components and socket wiring at the right distances to bloom.

Here are a couple of fit-check snaps:

[martin manning]

Most people put the D'lator tube between the OD and the PI, as that's where it sits in the signal chain. What's your thought for putting it first?

[amplifiednation]

Martin I was thinking the same thing.

Don you thought about lead dress in that area? I would think there would be wires crossing over the entire preamp which could be avoided by moving the d lator to V3.

Also how are you going to get the necessary voltage past B5?

Great to see a new build thread!

[DonMoose]

Most people put the D'lator tube between the OD and the PI, as that's where it sits in the signal chain. What's your thought for putting it first?

Since I have that big, empty corner to put the D'lator components in, away from the boardset and,

In external D'lator setups, there are shielded cables between the chassises and,

The distance available between the preamp board and power tube sockets is a bit short and,

The wire lengths and tag-strip components won't quite fit between board and preamp tube locations in a straight-on ('normal') configuration;

Lead dress in the preamp section can best approximate 'correct' by having a diagonal offset to create length between board and tube location and,

I can run the D'lator B+ across the rear bottom corner of the chassis, away from all the sensitive preamp bits.

At least, that's what I think so far.

This is a rather narrow chassis. I could reposition the transformers a bit - PT toward the front and OT toward the center - to get the tubes all aligned along the back edge, but they're all rather closer together than 'correct,' where with this biased setup, I can get get them a little farther apart.

[martin manning]

I thought you might say something like that, and I understand your reasoning. So there are no holes under the noval shields where they are standing, and you can put them anywhere you want? Still that is going to be tight. Do you have to angle the rectifier and relay supply boards to fit within the height? How will you mount those? I would at least try to draw it up with wiring to see how it will work out. What's the reason to use this chassis? Are you planning on using the cab too?

[Structo]

Yeah that is pretty cramped.

It's hard to fit all of it in a 19" chassis.

I'm all for saving money but if you think this will be a keeper then you might explore other chassis.

[amplifiednation]

Yeah I don't know how you are going to fit those boards in there, plus the D-lator? I'm not challenging you, I really am curious. How big is that chassis? Looks like 17" on your tape measure.

You might want to think about multi section can caps and mount the dropping string resistors right on them, maybe you can ditch the power board altogether?

Are you going to mount the loop parts on tag strips around the socket?

[DonMoose]

So there are no holes under the noval shields where they are standing, and you can put them anywhere you want?

Anywhere, provided I move the iron to accomodate.

Do you have to angle the rectifier and relay supply boards to fit within the height? How will you mount those?

They fit ... just. I may be dropping a 0.125" spacer in the cabinet to give me a bit more clearance.

I would at least try to draw it up with wiring to see how it will work out. What's the reason to use this chassis? Are you planning on using the cab too?

I'll be acquiring Visio in a bit, so can try to do a full layout. The amp was cheap and PV iron from that era has a pretty good reputation.

Yeah I don't know how you are going to fit those boards in there, plus the D-lator? I'm not challenging you, I really am curious.

No worries about potential offense - I'm here to solicit opinion and advice from the more experienced, after all. The can caps notion may pay off, but the plan is to put the PSU board over the PT's footprint, since it doesn't penetrate the chassis. The loop parts will probably go on a bit of perf so I can get it in and out easily.

Yeah that is pretty cramped. It's hard to fit all of it in a 19" chassis.

I was hoping the fact that I didn't need that gaping canyon for the PT might pay off. And having seen Heisthl's compact (Princeton, T100) layouts, I think I can get there. ... I think.

By the way, My intention is to mount the tube sockets from the inside to ease removal from this chassis in the names of mod and repair. Is there a reason that's a bad idea?

Thank all of you for your patience and your hard work in exploring these miraculous machines.

[Structo]

Well there are top mount and bottom mount sockets.
So it just depends what type you have on hand.

I never counted how many parts are in these things but it's about a bazillion.

[DonMoose]

Well there are top mount and bottom mount sockets.
So it just depends what type you have on hand.

I never counted how many parts are in these things but it's about a bazillion.

Oh, I'll share the BOM (with orderable P/Ns and links)

Um - this top/bottom mount socket thing - Would you care to point out an example or two? (ceramic, if you have that info handy) I thought it just needed a slightly bigger hole to pass the carapace (can't think of the word I mean).

[Structo]

I think it is more of a matter of the way the attachment flange is shaped than anything.

Here is an assortment of noval sockets that detail that.

http://www.tubesandmore.com/products/9_ ... ecommended

[DonMoose]

Nuts - no bottom-mounts that take shields.

Oh, well - more shopping,

Thanks, Tom!

[martin manning]

Don, some sockets I have (recent purchases) came with extra bayonet mounts for the shields. You can mount the socket inside and the shield on top.

[DonMoose]

Don, some sockets I have (recent purchases) came with extra bayonet mounts for the shields. You can mount the socket inside and the shield on top.

Yup - and Angela has some pretty colored ones that I can add to any noval socket lacking such. Less that $2/ea, too.

http://angela.com/blue9pinj-slottubeshi ... t7etc.aspx (blue)

Thanks!

[Structo]

I have used the colored ones before too.
I like them.

Something else you can do it polish the aluminum shield cans to a high luster.

I think one of the biggest difference between top mount vs bottom mount is the size of the hole in the chassis.
Bigger for bottom mount smaller for top mount.