Budgie SE Rev A prototype

a 3W single ended EL84 amp for home, work & school

Budgie SE Rev A prototype

Postby Shannon Parks » Thu Aug 21, 2014 10:01 am

Underside hook ups turned out pretty neat! I did a miscalculation on the bobbin width of one of the rear OPTs (it bumped up against the rear of the chassis), but I'll fix it for the production run. I may rotate it 180 degrees and place them almost touching so that you can easily connect Fast-On connectors. If not, I'll put 1/2" pieces of heatshrink tube on the exposed connectors. I *hate* to be shocked by B+, and those open frame outputs look like a perfect way to do it.

All the nickel plated screws will be replaced by black alloy screws in a few days when my order from FMW Fasteners shows up. They're my new favorite nuts-n-bolts place. Sorry, Fastenal!

Shannon
Attachments
budgieunderside.jpg
budgieunderside.jpg (670.83 KiB) Viewed 7119 times
longasblack.jpg
longasblack.jpg (574.03 KiB) Viewed 7119 times
User avatar
Shannon Parks
Site Admin
 
Posts: 3762
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Re: Budgie SE Rev A prototype

Postby TerrySmith » Thu Aug 21, 2014 10:22 am

Shannon, that looks really nice! Are you still planning to sell it with the OPT's? FWIW, I built my Budgie SE with the open frame Edcors and they sound every bit as good (to me anyways) to the GXSE-10's. The wife uses it daily in her sewing room.

I'll be sure to check out FMW fasteners, I've been using Bolt Depot.
T. Smith
User avatar
TerrySmith
KT88
 
Posts: 973
Joined: Sat Jan 31, 2004 12:51 pm
Location: Maryville TN

Re: Budgie SE Rev A prototype

Postby Shannon Parks » Thu Aug 21, 2014 10:53 am

TerrySmith wrote:Shannon, that looks really nice! Are you still planning to sell it with the OPT's?


Not sure what the game plan will be beyond getting both Rev A boards out (main PCB and top plate). Going to do tests over the next week comparing the XSE10s I bought with some XSE5s that Ty has loaned me. I'm assuming the XSE5s will be superior.

Also rethinking my 20/20 scheme for the headphones. I need to decide how useful are the SPL ratings of the headphone manufacturers. SWAG that over a certain level, use the 20/20. Under a certain level, use no divider. Need to read some datasheets, I guess.

Cranking Led Zeppelin's Coda album with the new Budgie SE and my Audio-Technica ATH-M50x headphones. [:)

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3762
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Re: Budgie SE Rev A prototype

Postby Ty_Bower » Sat Sep 06, 2014 9:00 pm

Shannon Parks wrote:Going to do tests over the next week comparing the XSE10s I bought with some XSE5s that Ty has loaned me. I'm assuming the XSE5s will be superior.

Also rethinking my 20/20 scheme for the headphones. I need to decide how useful are the SPL ratings of the headphone manufacturers. SWAG that over a certain level, use the 20/20. Under a certain level, use no divider. Need to read some datasheets, I guess.

Cranking Led Zeppelin's Coda album with the new Budgie SE and my Audio-Technica ATH-M50x headphones. [:)


For the record, those aren't XSE5. They're GXSE5.

I'm a headphone nut too. I keep looking for my favorites. How do you like the ATH-M50x? Compare them to the MDR-V6, if you can. I've recently been playing with a pair of UE-6000 and some on-ear Street 50, but I keep going back to my old Sonys.
"It's a different experience; the noise occlusion, crisp, clear sound, and defined powerful bass. Strong bass does not corrupt the higher frequencies, giving a very different overall feel of the sound, one that is, in my opinion, quite unique."
User avatar
Ty_Bower
KT88
 
Posts: 1494
Joined: Wed Mar 21, 2007 2:50 pm
Location: Newark, DE

Re: Budgie SE Rev A prototype

Postby Shannon Parks » Wed Sep 10, 2014 7:13 am

Ty_Bower wrote:For the record, those aren't XSE5. They're GXSE5.

I'm a headphone nut too. I keep looking for my favorites. How do you like the ATH-M50x? Compare them to the MDR-V6, if you can. I've recently been playing with a pair of UE-6000 and some on-ear Street 50, but I keep going back to my old Sonys.


I've caught myself once on that series designation, but I admit I get confused quickly with the Edcor scheme. (lol)

My MDR-V6s which are working great (wifey loves them), but the pads fell apart and the replacement pads were a tiny bit smaller and with half the foam. They just weren't as comfortable as they had been. I started off with some nice Sennheiser HD558 headphones, but the open air design isn't a fit for me. Too noisy for those around me, and no isolation for me, particularly bad when the forced air turned on (isn't a headphone's noise floor a key figure?). So when for the M50x's and love them. They adequately isolate, are comfortable for my fat head, sound great, etc. Build quality seems fine. We'll see if they last as long as the Sony's. The "x" designation of the new M50 means we now have a detachable cord and the unit comes with three cords. It's intuitive and works great. I like the short cords for my notebook and use the coiled one with my Budgie SE. I would heartily endorse it for an every day pair of headphones.

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3762
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Re: Budgie SE Rev A prototype

Postby Auricle » Tue Sep 16, 2014 2:52 am

Going to do tests over the next week comparing the XSE10s I bought with some XSE5s that Ty has loaned me. I'm assuming the XSE5s will be superior.


Hi Shannon, Have you reached any conclusions as to whether either of these transformers are superior to your originally-spec'd GXSE10 ?

Regards,
Auricle
Auricle
 
Posts: 41
Joined: Mon Jul 28, 2014 1:22 pm
Location: Vancouver BC Canada

Re: Budgie SE Rev A prototype

Postby Shannon Parks » Fri Sep 19, 2014 8:47 am

Auricle wrote:
Going to do tests over the next week comparing the XSE10s I bought with some XSE5s that Ty has loaned me. I'm assuming the XSE5s will be superior.


Hi Shannon, Have you reached any conclusions as to whether either of these transformers are superior to your originally-spec'd GXSE10 ?

Regards,
Auricle


The GXSE10 is superior to both of them with more primary inductance, but the smaller outputs are handy in that they should make the build with the new top plate *super easy*. Even with a DIY chassis like the 12x8x3 aluminum Hammond, it couldn't be easier drilling a couple #8 holes.

As far as head to head tests vs the two open frames, I haven't done that yet. But I will shortly. ;)

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3762
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Re: Budgie SE Rev A prototype

Postby lego4040 » Thu Dec 11, 2014 4:03 pm

Shannon I got mine up and running but troubleshooting is my next step. I can say that when looking at your PDF pages for build you show CT for 6.3v going to A but your build here had it going to B. I have the same purple board here. I did fire it up at first with it soldered to A and made the idiotic mistake of having the 12AX7 in the EL84 socket and vise versa. :'( I did not realize this until I fired it up with my iPhone hooked up and playing. Music started coming out of speakers and then I got a high pitch sound. After realizing this I powered down and swapped tubes correctly but still got high pitch squeal. I changed tube set and got same squeal. I powered down, discharged caps and tested all resistors and they turned out good. I can't test caps for damage unless I pull them out. They didn't blow so that's a good sign, one thing I did was put snubber caps on the under side as one of the fellas here did with his build, I need to check there
lego4040
 
Posts: 20
Joined: Sun Oct 12, 2014 6:07 am
Location: The Big Apple

Re: Budgie SE Rev A prototype

Postby EWBrown » Thu Dec 11, 2014 5:26 pm

Check to make sure that the NFB connections aren't reversed, that would make it positive feedback (oscillating) and that would make it squeal or growl.

Simple to fix, just reverse the two secondary OPT connections

/ed B
Real Radios Glow in the Dark
User avatar
EWBrown
Insulator & Iron Magnate
 
Posts: 6389
Joined: Wed Mar 19, 2003 6:03 am
Location: Now located in Clay County, NC !

Re: Budgie SE Rev A prototype

Postby lego4040 » Fri Dec 12, 2014 11:15 am

I'll check those NFB's out, thanks. There is a little difference between the PDF and the purple board build. The PDF jumpers and the board are opposite for the OT screen and plates. Thanks for the advice
lego4040
 
Posts: 20
Joined: Sun Oct 12, 2014 6:07 am
Location: The Big Apple

Re: Budgie SE Rev A prototype

Postby lmaynard » Fri Dec 12, 2014 3:08 pm

Hi To all. Looking at one of posts concerning point (B) on the circuit board the brown/white center tap connects here. Looking at the PDF it shows Right output trans. connection from pin 3 ot the tube going to (A). The Left output connection from pin 3 of the tube to (B). Are these A&B points on the board
the ones your asking about?
Thanks,
l.maynard *)
lmaynard
 
Posts: 7
Joined: Sat Jan 04, 2014 11:36 am
Location: cary, n.c.

Re: Budgie SE Rev A prototype

Postby lego4040 » Fri Dec 12, 2014 8:36 pm

The A on the Board is the CT for the secondaries on the 6.3volts. On my Board(purple) there is a A&B, not sure what B is for. I'm coming from guitar amp building and hifi is new. Here is my noise on my build via YouTube http://youtu.be/py6u11u9Bqs
lego4040
 
Posts: 20
Joined: Sun Oct 12, 2014 6:07 am
Location: The Big Apple

Re: Budgie SE Rev A prototype

Postby Shannon Parks » Sun Dec 14, 2014 7:59 am

[A] and [B] are just the cathode bias test points for the EL84s. I've moved them around from the previous revision. I changed the heater center tap hook up from [A] to [B] just because it is closer to the edge of the PCB and further away from electrolytics (less chance of a soldering iron melt job on a cap). So either [A] or [B] is fine for the 6.3VAC center tap - it doesn't matter.

lego4040, that sounds like a typical reversed NFB oscillation as Ed points out. First just disconnect the feedback (disconnect connection at J8). Then retest for oscillation. It that fixes it, swap the wires at your Edcor OPTs (8 ohm and GND) and reconnect J8 and retest. If it is still there, possibly we damaged C9 or C10 by shorting HV to the cap with the 12AX7.

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3762
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Re: Budgie SE Rev A prototype

Postby lego4040 » Sun Dec 14, 2014 12:06 pm

Will try, on your PDF you show OT plate(blue to pins 1) and screens(white/blue to pin 2) on the board it's reversed. I will make sure all is correct there as well. As for C9&C10, I checked them over and over while on the board and they show a 123 ohm reading? When I lifted a leg off the board I got the correct 1.2kohm reading. Weird to me
lego4040
 
Posts: 20
Joined: Sun Oct 12, 2014 6:07 am
Location: The Big Apple

Re: Budgie SE Rev A prototype

Postby Shannon Parks » Sun Dec 14, 2014 3:20 pm

lego4040 wrote:Will try, on your PDF you show OT plate(blue to pins 1) and screens(white/blue to pin 2) on the board it's reversed. I will make sure all is correct there as well. As for C9&C10, I checked them over and over while on the board and they show a 123 ohm reading? When I lifted a leg off the board I got the correct 1.2kohm reading. Weird to me


The manual changes from the red PCB to the purple PCB, and I haven't updated all the links yet (still some edits to do). Hopefully, I shipped you the updated manual that matches the PCB. Basically the old red board didn't really explain which was pin 1 or pin 2 - a problem.

Ultimately follow the PCB silkscreen on the purple board. I put it there to make sure it gets hooked up correctly. :) You should be able to ohm out a short between the plate connector on the OPT to pin 7, and likewise a short between the screen OPT tap and pin 9 (on the corresponding EL84). Obviously do these checks unpowered.

I think your caps are OK. Sounded like the typical NFB oscillation that happens to all of us. Disconnect J8 and test.

Shannon
User avatar
Shannon Parks
Site Admin
 
Posts: 3762
Joined: Tue Mar 18, 2003 5:40 pm
Location: Poulsbo, Washington

Next

Return to budgie se

Who is online

Users browsing this forum: No registered users and 1 guest

cron