70's style build 100 watt

[dcribbs1412]

Quick check of voltages are as follows...
I think they are in the ballpark?...might change string to get 4 and 5 up a little.
I'll try some different tubes first.
B+1 440V
B+2 437V
B+3 418V
B+4 266V
B+5 259V
Loop nodes
275V
235V

Darin

[talbany]

Darin
The sweet spot for the 2nd generation's are 185 V1 190-95 V2

Real Dlators can have in the 255V range on the pin 1 of the cathode driver section. Around 28-31V on pin 3 if using the 27K/1.8K combo.

The recovery amp has 230-235V on pin 6.

The B+ is indeed in the 335V range.

What is your dropping resistor for the PS node to the loop?

Good Luck

Tony

[dcribbs1412]

Darin
The sweet spot for the 2nd generation's are 185 V1 190-95 V2

Real Dlators can have in the 255V range on the pin 1 of the cathode driver section. Around 28-31V on pin 3 if using the 27K/1.8K combo.

The recovery amp has 230-235V on pin 6.

The B+ is indeed in the 335V range.

What is your dropping resistor for the PS node to the loop?

Good Luck

Tony

Tony
Thanks for the sweet spot voltages to shoot for.
spent a few minutes with it at lunch.
FET is not working properly...volume drops when switched on,
not sure about that. Also PAB does not seem to boost much.
I'm using 10m resistors. (no 22m on hand)I have to look at that closer also. Drop resistor for loop is around 75k then 33k I will double check.
I'll work on voltages as I figure out the FET and PAB problems.
Very much appreciate your time.

Thanks
Darin

[dcribbs1412]

Changed the drop string from 30k to 24k and now have 182V on v1 and 192V on v2.
I have 252V on pin 1 of loop
202V on pin 6 and 13V on pin 3...seems a little low
Drop resistor for PS node to loop measures 82k, might get a 75k(none on hand) in there and see if voltages come in line.

Darin

[amplifiednation]

Darin,
Your build is fantastic! Great job. Did you change any values on the PAB to make it more noticeable? Mine doesn't do much..

How do you correctly have the master(s) wired? Clean master?

[Structo]

Changed the drop string from 30k to 24k and now have 182V on v1 and 192V on v2.
I have 252V on pin 1 of loop
202V on pin 6 and 13V on pin 3...seems a little low
Drop resistor for PS node to loop measures 82k, might get a 75k(none on hand) in there and see if voltages come in line.

Darin

On my D'lator for which I used a Fender Reverb PT, I had 278v on pin 1 and 213v on pin 6.

The nodes measured 342v and 278v.

This is using the 27K/ 1K8 divider.

[dcribbs1412]

Darin,
Your build is fantastic! Great job. Did you change any values on the PAB to make it more noticeable? Mine doesn't do much..

How do you correctly have the master(s) wired? Clean master?

Thanks Taylor
still working on the PAB...same here not much change when engaged.
good to know yours does the same...I was looking for that big boost
the other PAB's have. Quick question is your .02 cap on the bass pot from
3 to 1 or 3 to 2?

My problem is the FET...it cuts the volume way down when engaged.
Not sure whats causing this...

As far as the master wiring...I'm still messing with it, not sure how to do the separate Clean/OD masters with the internal loop. Right now its wired as separate...but the loop also controls the volume. I don't think I have it right. I have no lead to the .05 of the loop. All of the internal layouts I have seen have a lead from the master to the .05 of the loop.

Tom
I think my loop voltages are a little low. I may change a dropper to up it a little, like to get the FET working first. What voltage do you have on pin3 of your loop?

Thanks
Darin

[Structo]

31v on pin 3 is what I recorded when I built it.

But every tube is different so you have to consider that.

I think I used a JJ 12ax7 when I first got it going.

Now I have a Rayethon LP 12ax7 in it.

[dcribbs1412]

Thanks Tom
still working on issues
I pulled the PAB relay...after a few changes I decided to go without it.
Jazz/Rock switch actually works better now...
Still working on the FET circuit. So far I really like this style D circuit...
Clean and OD has very usable tones. Hoping a working FET adds another
level.

Edit...Got the FET working...bias issue, big thanks to Martin Manning and his diagram for the guide thru. I have 19.6V on top...8.9V on bottom and callin it close enough for rocknroll. Hope to clean up some wiring and get her in a cab soon.

Darin

[dcribbs1412]

Before I get her in the cab I revisited the PAB relay.
Not sure what the problem is...seems to be wired like a normal PAB...
I've done searches for anything different for a 2nd/3rd or 70's style PAB,
but found nothing other than the normal wiring. It just seems to not do anything, in fact the rock /jazz switch doesn't seem to work with the relay in the circuit, but worked when I took the relay out and wired it straight.
Any comment or suggestions are greatly appreciated

Darin

[ToneMerc]

Before I get her in the cab I revisited the PAB relay.
Not sure what the problem is...seems to be wired like a normal PAB...
I've done searches for anything different for a 2nd/3rd or 70's style PAB,
but found nothing other than the normal wiring. It just seems to not do anything, in fact the rock /jazz switch doesn't seem to work with the relay in the circuit, but worked when I took the relay out and wired it straight.
Any comment or suggestions are greatly appreciated

Darin

Darin, these univ relays(vs the D relay in the layouts) and the different switch combinations can trick you up. What type of switch did you use for the R/J switch, on/off/on or on/on and how do you have it jumpered? Also, to keep the wiring simple I like place both 22Ms on the PAB relay. Try this, at the L and R middle terminals on your R/J switch, transpose the connections.

TM

[amplifiednation]

Before I get her in the cab I revisited the PAB relay.
Not sure what the problem is...seems to be wired like a normal PAB...
I've done searches for anything different for a 2nd/3rd or 70's style PAB,
but found nothing other than the normal wiring. It just seems to not do anything, in fact the rock /jazz switch doesn't seem to work with the relay in the circuit, but worked when I took the relay out and wired it straight.
Any comment or suggestions are greatly appreciated

Darin

I've got a very noticeable rock/jazz switch on my 2nd gen, but nothing for PAB. I used the same layout as you. I haven't had time to tweak anything though...but as you say, everything seems normal. I used on/on for R/J

[CHIP]

Darrin, Post some closeup pics of the PAB relay, R/J switch, and the tone controls, then we might be able to see what's going on with the PAB. My #183 builds PAB and R/J switch were screwed up until I finally wrapped my brain around it and got it right.

[ToneMerc]

I might be wrong, but I don't think the PAB boost will work with that hybrid layout as drawn. The bass pot doesn't have a reference to ground.

TM

[dcribbs1412]

Thanks guys
TM switch is a on/off...switched connections at mid terminals and still no go
Taylor...your comment earlier that your PAB was not working properly got me interested in figuring out why. Both of us using the same layout and all.
Chip I've been searching/starring and changing things so much I had to call on some more eyes and knowledge on this, but its gotta be something silly simple I am doing wrong. Here's some pics..I made the relay board(it was doing the same thing using one of Jasons pcb relay boards) brown lead goes to middle of bass pot..out of 22m resistors so 2x10m heat shrinked...
Really appreciate you guys and your time

Darin