Orange 86 Build Thread - no PCBs for sale

[guavatone]

Hi,
I know the BOM recommends a 14" deep 2-RU box for a pair with e88cc output drivers, but do you reckon a 12" deep enclosure would be close enough?

I just measured and 2 PCBs "should" fit.  Although, the Output transformers will need to be mounted on the side.  An this may cause a bit more crosstalk.  If you have a small PSU for P48 and relays and use AC heaters, this will save space on the sides.

Sorry for the delay folks.  This winter has been like having a third job doing snow removal.  I will get to other posts soon.

 

[guavatone]

-while seeing Jdbakker post on page 1 about D12 and D14
i was wondering if J2 and J3 need to be linked or not ?
-with the suggested hammond transformer
and 24v relays, i assume i have to use the voltage doubler and not tripler right ?
-are the 1/2W 100R from heater to Star Ground needed for DC heater  ?
if needed , should i put them on the PSU pcb from the LT transformer secondary to star ground
or on the preamp PCB ?
-You also suggested to wire EF86's pins 2 and 7 to ground , is this for both DC and AC heater or only AC ?
thanks for your help,
regards,
francois

Tha's for P48.  J2 is linked to J3 for Trippler.  Doubler is for the 24V suggested transformer.

for V1 just wire like the docs say.  They are the blue lines.  That is LT ground from the PSU PCB.
-I am not sure why you are asking this since the PCB has pins 2 and 7 linked already.

You may want to go with AC Heaters if you are fairly new to this.  I hope this helps. 

 

[pacemaker]

Thanks for your reply Guavatone,
I've wired everything as in the build manual,
I was guessing that the voltage doubler or tripler
was depending on the transformer secondary voltage
and as i bought the recommended hammond transformer,
i thought i have to use the doubler config, just needed to be sure.

i just saw a post about wiring pin 2 and 7 to star ground directly,
and i 'm wondering if this is just for AC heaters,
or if it's suitable also for both AC and DC heaters,
i allready have build everything so it might be easier for me
to stay with DC heaters 

sorry for all these rookie question but i'm on this build since one year
and i'm finally close to fire up the unit,
and wanted to be sure about everything .
Best regards,
francois

 

[guavatone]

np.  What was the post about VQ1's Pins 2 and 7?

 

[pacemaker]

A post from Ian / IMO

and also detached the jumper from pin 2/7 of V1 from the heater low and attaching it to the ground point nearest.

and your reply

YEs the EF86 should have pins 2 and 7 to ground and not AC.  There may be a mistake in the document.
So Jumper shield to the ground plan point on the board below(looking from the input/output section on bottom)
I generally don't like LT center taps and use 1/2W 100R to Star Ground.  Not to PCB ground.  Like in fender amps by the big old jewel lamp.

And i thought it logical, at least for AC heater
but maybe with your PSU, DC heaters, and a strong grounding scheme
It's not needed.
Regards,
Francois

 

[guavatone]

Oh!

Now I remember.  Version 1.5 of docs have correction with AC heater.  There was a mistake in the AC heater
diagram.  AC Filaments should connect the tube's shield to the preamp PCB's ground plane.

When using DC Filaments/LT/Heaters (too many names for one thing)...  We want the tube's shield to be wired
to LT 0V DC which comes from the PSU PCB.

Glad you are almost done.

 

[ethervalve]

do you reckon a 12" deep enclosure would be close enough?

I just measured and 2 PCBs "should" fit.  Although, the Output transformers will need to be mounted on the side.  An this may cause a bit more crosstalk.  If you have a small PSU for P48 and relays and use AC heaters, this will save space on the sides.

Hey thanks for checking Charlie; I'm not terribly worried about crosstalk. (Sorry I missed your message)
I got the 3-ru 12" enclosure and I'm thinking it'll be fine.
I'm planning on placing the final parts order tonight and start assembling on Monday.

So how's everybody coming along with their builds?

 

[imo]

Wanted to chime in that i finally figured out what was messing up the DI/relay part of the build.
I literally had replaced every single part on the DI, replaced the relay, replaced the transistor, checked everything repeatedly, and finally decided to snip the LED on the non working DI pcb. It solved the problem. My thinking is that somehow the LED was sourcing too much current. It was an ultrabright clear, whereas the other one was a standard red. The DI flips the relay now as it should. worth noting..For what its worth, i cobbled together a 48v/24v board of my own. This may not be a problem using the Guava powerboard.
Ian

 

[ethervalve]

Does anyone know the appropriate fuse for a two channel build for North American voltages? Would a 1 amp slo blo be alright?

 

[guavatone]

Lets do the math:

Filaments:
V1 2x .3A = .6A
V2 2x .6A = 1.2 A

Preamp:
under .03 x2 = .06A

Total = ?

Fuse = Total + 1/2A or so

 

[ethervalve]

Thanks

 

[imo]

charlie,
you wouldn't have an extra of the pad pcb's would you? i borked one just as i was finally wrapping up this build(using the plastic lorlins and trying to fit an old dakaware knob). Switch broke and lifted a couple of traces getting the old one out. I have a somewhat working board, but would love to have it done..
thanks
Ian

 

[guavatone]

imo, I PM'd u.

 

[ethervalve]

Hi all..
I'm getting close to finishing mine, but I've run into a snag:
The relay voltages are too high (20v for the 12v and 40v for the 24v).
I'm using the Hammond 164F24 (115v primary only http://www.hammondmfg.com/pdf/5C008-9.pdf ) and I omitted D7 and shorted C11 with a jumper. I confirmed that R11 (91R) and R12 (220R) are the values on the schematic. 
All other voltages are OK (48vdc/6.3vdc/290ish at the power link).
Thanks in advance for any clues.

 

[guavatone]

unloaded the voltages would be a bit high.  12*1.414=16.9 and 24V would be around 36V.  When the relays are engaged the resistor load and relay load will drop the voltage.  Did you test with them engaged?

 

[ethervalve]

Thanks for the quick reply Charlie. No I didn't try with the relay sections hooked up--novice paranoia.
I'll hook everything up and see if it works.

 

[guavatone]

You should be fine.  Test your mains.  my guess is that they are spitting out 120-125 VAC

 

[ethervalve]

Thanks Charlie. I'm getting 122.5 from my AC.

So... I powered it up and everything works and sounds great except for the DI functionality (neither channel is working).
With a 1/4" jack plugged and the LED installed the DI relay voltage goes down to about 34vdc. (BTW you were right about the output polarity voltage--in circuit it's almost a perfect 12v).
I had idiotically plugged the molex headers on both DI pcbs (VC-Ind; Ring; GND; and OUT) backwards so I hope I didn't destroy any components.

I was able to verify that test signal applied to the DI jacks was making it to the tip and sleeve pads on the main board, but I'm a bit confused as to what happens in the relay control section.
Edit: fixed grounding error--now everything works great!
(Aside: one of the things I like the most about this design is the 3-way Lorlin switch variable pad--great idea)

 

[guavatone]

Cool. Glad to hear you sorted it out.

 

[plinker]

Hi Folks,

Is there a sonic difference between the 12BH7 or e88cc for the output stage?
<edit: just found this on page 6 -- "I recall hearing something great with the 12Bh7 ef86 combo that the  E88CC/6922 did not provide.  It seemed to track the dynamics of the acoustic guitar I was recording.  It was like "that sound".>

Anything to add?

Thanks,
Jim