Rocket w/ Reverb

amplifiednation · Post by **amplifiednation** » Sat Feb 19, 2011 12:38 am

martin manning wrote:Looks like the layout is showing a typical arrangement: coax with the shield tied to the input jack ground, and the grid stopper spliced on the other end. If you need a piece I can put some in the mail.

Sure martin! That would be great! How is the ods cab coming?

martin manning · Post by **martin manning** » Sat Feb 19, 2011 1:34 am

The head cab is going slowly at the moment; another project is in the way. Your Rocket is coming together pretty quickly, though- how much cable do you need, about a foot?

This stuff is pretty fine, so when you make up this lead prepare the more difficult end first, which is the one with the resistor on it. You'll want to cut back the outer covering about an inch and then trim the shield braid back to that same point. Then strip the inner conductor back to ~1/8-inch of the outer covering, and make sure that there are no strands from the shield left to contact the inner conductor. Shorten one of the resistor's leads, spiral wrap the inner conductor around it and solder. Put some heat shrink over the solder joint, inner lead, and back onto the outer cover of the cable for a half inch or so. After you get the other end of the coax stripped, solder the other lead of the resistor to the input tube grid lug, with the body of the resistor close to the lug. On the jack end of the coax you can just strip the outer cover back, separate the shield from the inner conductor and solder them both to the input jack, with the shield going to the ground lug.

amplifiednation · Post by **amplifiednation** » Sat Feb 19, 2011 1:48 am

Killer sounds perfect! I can't wait to see if this amp works! I think work will be happy to have me back once it's all done!

Recognize the board martin? It worked perfectly thanks again!

martin manning · Post by **martin manning** » Sat Feb 19, 2011 7:41 pm

It's in the mail!

amplifiednation · Post by **amplifiednation** » Tue Feb 22, 2011 1:54 am

Getting ready for some start up tests. I reflowed a bunch of solder joints and put in some additional grounds that I hope will help. I'm sure I'll have to do some tweaking.

OOOh, also i don't have any EL84's. I gotta pick some up quick!!

angelodp · Post by **angelodp** » Tue Feb 22, 2011 5:22 am

Looking good, nearly there.

amplifiednation · Post by **amplifiednation** » Tue Feb 22, 2011 11:44 pm

alright, got my bulb limiter tests out of the way and we have an amp without shorts!! or so it seems...

I'm getting close to liftoff.

Recto and preamp tubes in.

Voltage readings seem wayyy off.

Heaters across the board are 3.25 AC. Why?? I came right off the PT??

Why are these so far off? My number is first/voltage chart second

B+1 is 328/290
B+2 is 323/279
B+3 is 173/212
B+4 is 105/187
B+5 is 100/183

Tube voltage isn't even close to where it should be

M Fowler · Post by **M Fowler** » Tue Feb 22, 2011 11:51 pm

The filament you have is 3.25vac on one pin and across both is over 6 volts.

Your voltage is the larger numbers? Depends on which PT you used and which taps such as 300v verses 260v. The voltage chart I believe is for 260v tap.

amplifiednation · Post by **amplifiednation** » Tue Feb 22, 2011 11:59 pm

M Fowler wrote:The filament you have is 3.25vac on one pin and across both is over 6 volts.

Your voltage is the larger numbers? Depends on which PT you used and which taps such as 300v verses 260v. The voltage chart I believe is for 260v tap.

Mark,
How does that add up? I'm getting 3.25 on each of the brown heater leads coming direct from the PT, so how does that get me 6.3vac? I went across 4/5 and still I'm only 3.25. Does that makes sense?

I think i used the lower taps...or at least I meant to. They are RJ transformers Hayboers. i followed the colors from the normster layouts. I'm getting 260 at the rectifier

ChrisM · Post by **ChrisM** » Wed Feb 23, 2011 12:40 am

DMM set to AC V, one lead on pin 4/5 the other on pin 9. What do you read?

M Fowler · Post by **M Fowler** » Wed Feb 23, 2011 12:48 am

Wait these are unloaded voltage readings right no tubes in?

When you put the tubes in then you will get accurate readings.

Yeah pin 9 to 4/5 is 6.3vac or close.

amplifiednation · Post by **amplifiednation** » Wed Feb 23, 2011 1:48 am

Ahh yes I get it now...and I got the correct readings for the heaters. I was grounding to the chassis for the readings and only measuring with the hot lead. I got to find a thread on taking voltage readings!

Thank you mark!

amplifiednation · Post by **amplifiednation** » Wed Feb 23, 2011 2:00 am

Thanks everyone for your continued help my rocket will be flying soon

Normster · Post by **Normster** » Wed Feb 23, 2011 3:24 am

amplifiednation wrote: B+1 is 328/290
B+2 is 323/279
B+3 is 173/212
B+4 is 105/187
B+5 is 100/183
Tube voltage isn't even close to where it should be

B+1 & B+2 look OK. B+3 - B+5 don't look right at all. With no tubes installed, those voltages should be much higher. I looked closely at your PS cap wiring and it looks correct. Not sure about the ground side of your PS caps. Are the top 3 caps grounded?

angelodp · Post by **angelodp** » Wed Feb 23, 2011 4:47 am

Does the power supply need an additional node for the reverb section.

Ange

The Amp Garage

Rocket w/ Reverb

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Almost there

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Reverb node