Orange 86 Build Thread - no PCBs for sale

[Holger]

Are you saying it's an "in your face" sound?

Top notch build Holger!

But I still have yet to understand the need for a meter on preamps.  It would distract me from making sources sound good in the studio.

Yes, that's what I tried to say 
It's more or less a correct translation of a response I got.
The meter: well, I had it, it looks good, so, why not why not putting a VU meter in such a build?

Thanks for liking. I've lend it out ot a sudio owner here who has access to some fine pre amps like Tube Tech.
He prefers mine over a wide range of signals.
I would say that this pre amp is the pre amp for vocals and guitars.
No additional EQ is required. Just use a good microphone. That's it.

 

[buildafriend]

Thank you.

Here's the pad-BOM. Looks to be -15 and -20 db.
My excel doc (v1.4) has multiple sheets, PAD PCB is the 4th one.

 

[guavatone]

I hope it works out for you soon buildafriend. if  u are stuck msg me and we can talk or something. You will soon be there I hope.

 

[junkface]

been looking into building a redd style pre for a while and this project seems like a really adaptable (read: fun) one. obviously with the varied methods and sourcing the price tag will change but I'm wondering what the build price has been (ballpark) for y'all.
also, are there PCB's anywhere out there still? I'm not opposed to custom fabricating one or just cutting it out of the design all together but just wondering.

 

[alexc]

Hi Buildafriend - hopefully you can get this guy going soon.

> I hear buzz and not much sound passes through

You need an 'audio probe' help figure out where the signal goes futz. I use a simple cap/resist thing which plugs into some cheap, self powered pc speakers. That way if you 'probe' a hot spot in a bad way, you won't blow an expensive computer-connected audio interface.

> I have not added the two 100 ohm resistors to ground on the AC heaters. I followed the directions for the jumping the proper pads for AC heaters.

The heater balance resistors can make a small difference but not relevent so far. This is a 'fine tuning' thing.

> The screen on the CMMI7C is not grounded. The mic buzz's when I touch the mic body.

Traffo shield/screen connection is recommended but shold not cause any noticable buzz when touching your mic. That indicates deeper grounding problems to me.

> The DC voltage from HT+ to HTGND is 286 volts which I think might be too low?

286V is fine - spot on I would say. The main thing is that the series pass transistor has some volts to 'regulate'. So as long as it is fed with something, say 7V or so (from memory) more than the output, it is regulating and your output is fine.

> V1 voltages


Pin 1 89 VDC      -> screen: a little high compared to plate, but should work
Pin 2 10mV DC  -> shield : should be grounded in general
Pin 3 1.7 VDC    -> cathode : looks fine at around 1.7mA thru 1K cath resistor or so
Pin 4 6.9 VAC    -> heater - bit high but should be OK
Pin 5 6.9 VAC    -> as above
Pin 6 73 VDC      -> plate : a little low compared to screen but should work
Pin 7 0 VDC        -> shield : looks good
Pin 8 1.7 VDC    -> suppressor : connected to cathode so looks good
Pin 9 0 VDC        -> grid : should be at dc ground, so looks good

Basically OK here for now.

> V2

Pin 1 0VAC          -> plate  wtf ??  Looks like a dud measurement. Should be 145Vdc or so
Pin 2 -10mV DC    -> grid : should be at dc ground but reasonably close
Pin 3 3.7VDC        -> cathode : looks OK for 9.25mA thru this cathode
Pin 4 6.9 VAC      -> heater : should be 6.3Vac but will work
Pin 5 6.9 VAC      -> as above
Pin 6 0 VDC          -> plate  wtf ??  Looks like a dud measurement. Should be 145Vdc or so
Pin 7 10mV VDC  -> grid : should be at dc ground but reasonably close
Pin 8 3.8 VDC      ->  cathode : looks OK for 9.5mA thru this cathode
Pin 9 300mV DC  -> heater centre tap : not connected for this tube so this is a bit suspect

ECC189/6ES8 is pin compatible with ECC88/12AU7 with the proviso that the heater is 6.3V only, on pins 4,5 - which you have. So thats fine. Your pin 9 looks high with dc - you need to check the heater ac supply option wiring.

Your plate values are wrong - but you have some cathode voltages which look good and therefore cathode current, indicating at least one side is conducting.

Check those again - if they are not at 290V when first powered on,dropping to 145V or so when unit is warmed up, then you have a problem. Trace the supply thru R14 and onto the plates.

----

So get that sorted and then you can move onto the next parts.

In general, the thing that confounds a little is the connection of the audio and heater grounds (dc heater).
They use jumpers to provide options for seperation between the two.

So double check you have the grounds properly connected on the pcb and have audio ground where you think you should.

Beyond that, check your overall grounding - the pcb has a star ground point on it, which you look like you have connected to correctly. I'm assuming your 'zap-o-kill' mains connection is properly earthed. If you are still alive, then I guess you have.

XLR pins 1 should be connected to chassis close by. Shielded cable is recommended - start with no shield connections. The you can ground one end at the pcb side and see how that works out. Also then the other. It probably will make no diff any ways, but worth a try in troublesome noise situation.

That heater jumper is probably best done under the board but should currently work.

Not much else - there are no other grounds to worry about really - it's all about the star and the onboard jumpers to make sure audio ground is connected.

The well pi-filtered HV virtually ensures quiet operation, and ac heaters should be fine too.

Cheers
Alec

 

[rock soderstrom]

Hi, voltages on pin 1 and 6 on the second tube are wrong. ECC189 is not a drop in replacement for the E88CC in this application but this is not your problem.

Edit: alexc was quicker!  8)

 

[buildafriend]

8) thanks guys.

I'll be back on the horse with this soon.

 

[guavatone]

Hi Builda.  Is the squish pads jumpered? They are next to the output.  Also check the coupling cap above V1 on your picture is soldered to the correct pads.

You def want military ecc88, but the basic one should pass signal but be noisy.

v2 anode should be much higher. Check with dmm

Also try without Relay to rule that out.

 

[buildafriend]

Squish is jumpered. All components are in the proper pads with correct orientation. I could see why you might think a component lead is in the wrong spot. Some of my cap foot prints are too large and I had to squeeze them in. That's why some look sort of twisted.

If the relay is not getting power, will I not have any input signal? Because it's in there but it has no juice going it's way.

You called it alex. Bad measurement on my end. I have 135vdc on v2 pins 1 and 6.

I just have to wait until I get a few bucks to buy the proper v2. If I had money right now, my enclosure wouldn't be an electrical box that came off of a wall during studio construction. What a dang tease!

 

[rock soderstrom]

Hi, VR1 is for fine tuning the gain, for instance in stereo use.

 

[iomegaman]

I finally got around to building my second channel of this...using the DC option...now as a full disclosure I am using soviet tubes I got from evilbay...and have traded out V2 with 6DJ8's of american origin...but here's my problem...with both channels hooked up my voltages are all over the map, the first channel works fine until I plug in channel 2 (and vice versa) my dc heater voltage sits at 6.3 until I plug it into a channel and then it dropd by about half...I am wondering if the psu is not enough to drive two channels especially in Soviet 6N32's...? They have a minimum of 5 something for dc heater...I built the psu Guavatone provided as per build docs...

My second question pertains to the "PWR-Link" on the board...I just assumed this was for simply running second channel without goign back to psu, sort of daisy chaining them together...and i have gone directly to the psu for both dc heaters...am I missing something here?

With either channel operating as a single unit they sound great (other channel completely disconnected), but I cannot seem to get two channels at once and channel "A" gets incredibly weak while channel "B" gets ugly distorted no gain...

 

[guavatone]

The PWR link is for the HT 300vdc rails. It sounds like you are using it for LT.  No?

Is your V2 HEATER jumpers on pcb hooked up correct?

 

[iomegaman]

No I am not using it...I'll double check but I am using only 6.3 volts since the build docs make it clear that the psu cannot support 2-12 volt heater channels I'm starting to think my tubes are funky...I will order some fresh consistent Western tubes from tube depot or something....

I used Edcors for all of it (except channel 1 input which is a Jensen JT-13k7A (which was another anomaly I noticed it is only rated at 1:5.9 and the edcors reversed should have more gain, but they do not...)

I noticed as well on my 2nd channel that I cannot use the CT on the input tranx AT ALL...it kills the input...(wired in reverse of course WSM 10k/150)...

 

[junkface]

finally getting around to sourcing this project, and having a heck of a time finding the grayhill switch in QTY less than 25. Wondering if I could use a non shorting switch or if anybody has a pair of the shorting versions they'd be willing to part with.  71BF30-01-1-12S-F is the correct switch in the BOM, 71BSF30-01A12N is the non shorting version I was considering FWIW.

 

[guavatone]

I hope you are enjoying this project Junkface.

Try here?
http://www.hairballaudio.com/catalog/parts-store/switches

Non-Shorting should be fine. There may be some small clicks and pops. but as long as there is some resistance, and there is R-FB-1, in the Negative Feedback Loop you should be golden. maybe just try it with a cheap alpha switch first.

See schematics doc

PS
What happened to PtownKid? wasn't he selling some?  I thought someone was.

 

[ethervalve]

Hi all,
After several years of working flawlessly, my Orange86 has recently started giving me some trouble in the relay and phantom voltage supply.
Unloaded (wires removed from the terminal blocks), I can get the +24v and +12v back, but I'm not getting any +48v.
This was initially just an intermittent problem but now it seems like it doesn't want to go away. I checked all the diodes out of circuit and they read OK.  I tried replacing the LM317 and it didn't help.
Even though the secondaries of the Hammond 164F read OK, do you think it could possibly be to blame ? It looks as though it's been hot (foil stickers peeling).  Also the fact the all three voltages are giving me trouble under load could be a clue, right?
Thanks in advance for any help--this is probably my most used, most-loved, piece of outboard equipment!

 

[guavatone]

Hi Ethervalve. Glad you've been enjoying th O86. If you remove them lm317, what is the voltage between R5 and ground?  I would also check the P48 switch  PCB resistor, led and cap connections and the switch. If there was a short on P48  after the reg. Let's see what's going on before the reg to isolate the issue.

 

[ethervalve]

Thanks Charlie!
You got me thinking in the right direction with the search for shorts. It turns out that all my woes led back to a bad solder joint on the J2 to J3 jumper so the ground connection was intermittent (oops!). It's working great again!
Have a nice weekend and thanks again for sharing this great design.

 

[guavatone]

Sure thing. Power to the people! 

 

[kosi]

short question. What are the values for R1, R2a and R2b on the psu board ? I'm talking about the heater section.
Are they really needed ?
thank you !