Mojotone JTM45 Schematic in Emailable Form?

[M Fowler]

The quality of the mojo garolite boards is terrible, board chipped, not cut straight, and turrets were not in straight line (where they should have been), so I used my own.

Sure it would have functioned but if your going to build an amp, do it well and looking good is important too.

Mark

[martin manning]

...and shipping a kit with parts that don't fit the board is pretty cheesy.

[The New Steve H]

If he's crazy enough to splice tiny wires onto his resistors, I am sure he has what it takes to get the job done. I guess we'll be fine.

[ToneMerc]

...and shipping a kit with parts that don't fit the board is pretty cheesy.

True, I know George of MetroAmp set his kit board up so that the turret spacing wasn't as wide, which facilitated the use of modern resistors like Xicon with the shorter leads.

TM

[Phil_S]

While it is really convenient to use a board made specifically for the layout, you can often get close by simply using a very inexpensive generic board like this one in the picture. There is an added advantage, too. It forces you to think about the layout. I always learn something in the process and building with this type of board and it has always worked out fine, even if a bit unconventional. Not sure how this picture will show, but you might be able to see where I marked it with a fine point Sharpie. Sharpie rubs off with a rag/q-tip and alcohol. These can be bought from Apex Jr. (look in New Arrivals) for $4 and sometimes less on eBay. The price point is so low compared to made to amp turret boards that I have lost my desire for the expensive stuff.

[surfsup]

The quality of the mojo garolite boards is terrible, board chipped, not cut straight, and turrets were not in straight line (where they should have been

I rarely use my drillpress. Too big, bulky, timeconsuming, and hard to use. I found the $20 I paid for the watts drill template was well worth the money. Its a piece of thin gauge steel 3.125x12" with holes popped every 3/8". I just hand drill with it on top of my paper template (centers aligned) and you can't see the slight errors from holding a drill by hand unless you looked sideways down the edge of the board. Popping holes with a hand drill is 3x faster for me. You can see it in this pic with a turretboard I built for a 4 gain Express I'm doing now:

[img1552]http://www.chicagocadcam.com/ChrisHahn/ ... /board.jpg[/img]

[ToneMerc]

I found the $20 I paid for the watts drill template was well worth the money.

One man's treasure is anothers man's junk, I really don't like mine and it's about 3 steps from the trash bin. I prefer to just make a template in Visio.

TM

[The New Steve H]

Now my vet friend is concerned because this amp has EL34 tubes and a JTM50 transformer.

I told him to put it together, attach the current limiter, and turn it on.

[The New Steve H]

You guys are hardcore with the circuit boards. I do mine freehand on the drill press. I draw lines with a ruler and then go to town. I figure if it's within 1/32, it's okay.

To make sure the standoffs line up right, I tape the boards to the chassis and drill through them. The holes may be off, but if they're all off in the same way, they'll still work.

[ToneMerc]

Now my vet friend is concerned because this amp has EL34 tubes and a JTM50 transformer.

I told him to put it together, attach the current limiter, and turn it on.

What's the concern? That would be the proper output tube/output transformer plate load combination.

However, like i said in my previous post, I'm confused as to what's in the kit. On the website, I see mention of the 1987 circuit and I see what looks like 1987 parts, but it mentions a JTM45 type kit. If i didn't know any better, it appears to be Plexi 50 kit with a tube rectifier.

TM

[The New Steve H]

I haven't seen this thing. Just the schematic and layout drawings.

[ToneMerc]

I haven't seen this thing. Just the schematic and layout drawings.

JTM45: generally uses KT66 tubes and either 6.6K, 8K or 9K OT

JTM50: really a JTM45 with either tube or s/s rectification, EL34 tubes, 3.4K OT w/buried 100V tap

1987(Plexi 50), split cathode circuit, EL34, 3.4K OT

TM

[overtone]

I found the $20 I paid for the watts drill template was well worth the money.

One man's treasure is anothers man's junk, I really don't like mine and it's about 3 steps from the trash bin. I prefer to just make a template in Visio.

TM

I picked up a few "junk" perforated sheet metal samples from a friends architectural office. I use these as drill guides, but still draw up the layout as a template in CAD to the same spacing beforehand, so it is paper layout under a drill template. I don't use the drill press much now.

[surfsup]

I found the $20 I paid for the watts drill template was well worth the money.

One man's treasure is anothers man's junk, I really don't like mine and it's about 3 steps from the trash bin. I prefer to just make a template in Visio.

TM

I picked up a few "junk" perforated sheet metal samples from a friends architectural office. I use these as drill guides, but still draw up the layout as a template in CAD to the same spacing beforehand, so it is paper layout under a drill template. I don't use the drill press much now.

Tonemerc, same here. Notice the CAD layout, then the completed board, then the drill guide. I use the drill guide to not have to worry about if the drill crawls. The holes are all pretty straight and superfast. I tried the drillpress. Geezus it was like an hour and a half. With a hand drill I can drill and mount the turrets in less than 30 minutes and have less to put away afterwards.

[steven21042]

I'm the Vet/newby/PITA that's been buggin' the NEW STEVE H about this amp kit. I guess the real problem is that I have NO INSTRUCTIONS & only my limited electronic skills to go on and don't want to blow up or otherwise incinerate this kit I've waited so long to get. The little bit I think I know about the 45 is that it uses KT66s (?) and my kit came with EL34s. Both OT & PT are labeled "JTM45" but there's mention of a 1987 circuit. So I really only have my gut and the guts of others to go on.