JJS designed Submini Amp

himister · Post by **himister** » 26 Mar 2010, 10:47

Fellas...I apologize once again. I redraw this one from the pic posted at JJ's site and done little mess with ground plane, I changed mistake I made with jack connection...it was some time ago when I drew this one, so I forgot that didn't finish it.
Here is the new layout and transfer and also a SprintLayout file so if anyone would like to make some changes, feel free to go.
Rar file needs to extracted to C:\ of your hard drive so the original JJ's layout picture can retain settings made for redrawing and comparing. If anyone spots any other mistakes, lemme know and I'll make changes when my time allows.
Cheers.

Layout:

JJSUBAMPlay.pdf: (20.62 KiB) Downloaded 555 times

PCB:

JJSUBAMPpcb.pdf: (15.18 KiB) Downloaded 404 times

SprintLayout project file:

JJSUBAMPSL5.rar: Extract to C:\; (85.95 KiB) Downloaded 341 times

criszu · Post by **criszu** » 27 Mar 2010, 16:25

hey....about the tube. Are 6021w and 6111wa same as with 6021 and 6111? Or the it's only Philips and Raytheon?
My local store only sell 6021w and 6111wa. I ask the owner, he doesn't know about those tube, are same as 6021 and 6111?
I google the datasheet for 6021w, but I can find it.
Does anyone know?

Wilco · Post by **Wilco** » 28 Mar 2010, 08:10

No problem, you can use those 6021W and/or 6111WA.

Here's some more info:

http://amps.zugster.net/projects/subminiature

viewtopic.php?f=2&t=511&start=60

bancika · Post by **bancika** » 28 Mar 2010, 20:20

6111 should be even better for output stage, but are lower gain so I wouldn't use them for V1 unless that's what you need...

Wilco · Post by **Wilco** » 29 Mar 2010, 10:25

bancika wrote:6111 should be even better for output stage, but are lower gain so I wouldn't use them for V1 unless that's what you need...

That is in fact exactly what I did: 6021 for V1, 6111 for V2. I found this the best balance between gain/overdrive and available clean headroom. I don't really play high gain stuff, but even in this configuration it has more than enough distortion on tap.

I made tube sockets just like JJS did: http://jjs.at/electronic/class_a_subminiature_5.png so I could try different tubes in V1 and V2. I tried all different combinations of 6021, 6111 and 6112, but I liked 6021 in V1 and 6111 in V2 the best.

bancika · Post by **bancika** » 29 Mar 2010, 12:41

love when practice confirms theory

criszu · Post by **criszu** » 07 Apr 2010, 16:06

My nixie powes supply won't work....what inductor I should use??
I use 100uH 2.5 amps http://www.mouser.com/ProductDetail/Fas ... m%2fYrw%3d

and this one, 100uH 1 amps http://www.mouser.com/ProductDetail/Fas ... m%2fYrw%3d

but they don't work, I'm affraid they blow. What inductor I should use for these nixie power supply?
Please any help, I don't have any experience with inductor.
Thank's

frequencycentral · Post by **frequencycentral** » 07 Apr 2010, 16:54

I've had good luck with this one in the nixie smps:

http://www.rapidonline.com/sku.aspx?tie ... ef=88-1630

Maybe you can check the spec and find something similar at mouser.

I've tried the first one you linked to, but it doesn't play nice in the 555 smps. It works really well in a MAX1771 based smps though.

lunchie · Post by **lunchie** » 08 Apr 2010, 21:40

I used this one with success - I am getting 300+V while powering 2 12ax7s

Mouser part:
652-RLB0912-101KL

daz · Post by **daz** » 15 Apr 2010, 14:24

Hi all,
Well finished building it and it powers up and gets sound!

Excuse the dirty enclosure, dodgy paint is coming off the OT I sprayed. I'm refinishing it all later.
I've left the dc jack not attached to the enclosure until I've refinished it.
However:
- i get high pitched distortion / whistling and fartiness even when volume is turned down low. I tried reversing the primary wires but it made no difference.
- 5v fan does not work with dropping resistor (but goes high speed at 12v!)
atm the nixie power supply is tweaked to B+ 165v using the standard 100uf inductor supplied with the ledsales kit. I even tries upping the B+ alittle and it made no difference.
I'm using two 6021 and a 12v 2A switchmode power supply.
Any thoughts?

lietuvis · Post by **lietuvis** » 15 Apr 2010, 15:59

hi Daz , try it with normal regulated power supply and tell the difference

daz · Post by **daz** » 16 Apr 2010, 04:49

lietuvis wrote:hi Daz , try it with normal regulated power supply and tell the difference

Normal regulated power supply makes no difference. I can hear the tone of the amp. It's just like another layer of noise and distortion on top.
I had one of the electro caps round the wrong way (thank god it wasn't the filter caps!) but didn't make any difference when corrected.
Might have to check my grounding scheme.

Edit: actually come to think of it, might be a microphonic tube that i'm hearing....

frequencycentral · Post by **frequencycentral** » 16 Apr 2010, 06:19

Just a guess, but removing C12 might remove the whistling.

daz · Post by **daz** » 16 Apr 2010, 07:08

Thanks I'll suss it out.
Looking at Wilco's gutshot on the 1st page, it does look like he had the secondary and common OT wired around the wrong way on the PCB?

Wilco · Post by **Wilco** » 16 Apr 2010, 07:38

I don't think so. Amp was (and still is) working just fine as it was on the pics.
I did have quite some oscillation at first, which was easily dealt with by making the OT leads shorter and leading them away from the signal path some more. You could try "manipulating" the leads with a pencil while playing, to see if the high pitched whining goes away.

daz · Post by **daz** » 16 Apr 2010, 13:13

Sorry Wilco didn't mean to sound critical. In fact appreciative for all the help you've provided.
I actually got it all working now. It was a microphonic tube in the end.
It sounds pretty good - alittle too edgey with the strat so may lower or remove c12

Wilco · Post by **Wilco** » 16 Apr 2010, 19:53

Haha, and I didn't mean to sound irritated.

I just really didn't think I had the wires around the wrong way.
But, you've got me thinking, so I actually tried changing out the green and black leads on the OT this afternoon. Didn't make any difference in my amp. I guess changing the red and blue wires doesn't either then.
Glad you've got your amp working right. Time for some mods then?

frequencycentral · Post by **frequencycentral** » 16 Apr 2010, 20:05

....but don't you guys yearn for more features? MOSFET boost, tremolo section, pre amp output, dummy load.....

Wilco · Post by **Wilco** » 19 Apr 2010, 20:24

Hey Rick,

Would you mind telling us some more about this latest creation of yours (not to mention post some gut shots)?

daz · Post by **daz** » 22 Apr 2010, 05:37

Finished - did a refin.
sounds good. Should note you need to fiddle with in internal wiring placement as it's susceptible to noise.
I'll do some clips shortly.