diy*tube clementine project (discontinued)

sweet & juicy SE amp for 1626 Darlings and the 6L6 family

diy*tube clementine project (discontinued)

Postby Shannon Parks » Sat Aug 06, 2011 2:44 pm


Manual:

Clementine Darling 1626, Clementine 6L6/KT88/EL34 and Clementine ULtra Manual with Schematics, Parts Lists, Voltage Charts & Hookup Diagrams
PDF MANUAL


Parts List & Mouser BOM:

Clementine Darling 1626 Parts List & Mouser BOM (Easy BOM entry link)
Power transformer is the Hammond 269EX, or 369EX for universal 120/240 line voltage. Output transformers are the Edcor GXSE15-8-5K (these are for 8 ohm speakers).

Clementine 6L6 (6L6GC/807/1625/6BG6) Parts List & Mouser BOM (Easy BOM entry link)*
Power transformer is the Edcor XPWR005-120. Output transformers are the Edcor GXSE15-8-5K (these are for 8 ohm speakers).

*Added two different values on the parts list and BOM for R18 & R19 depending on dissipation > or < 19W, selected for your power tube type. Changed R17 & R20 to 1.2K. Cathode networks are either 667 ohms or 720 ohms.

Also note that some old 6L6s need pin 1 and pin 8 to be jumpered together, as they are not internally connected. Go ahead and add them to V2 and V3 after you solder the socket in place. It can double as a cathode bias test point clip and permits EL34s to be used.

Chassis Docs:
Board Outline in PDF - Be sure to print to scale.
FrontPanelExpress File for Full Top Plate - Courtesy of BadAssBob using Edcor GXSE10 outputs and a PA774 power transformer
FrontPanelExpress File - Board Outline Only

Cost:
Discontinued

Notes:

4/25/13 - Added manual with more ULtra documents.
12/23/11 - Fixed the voltage chart for the Darling build that had pins 1 & 8 swapped. Fixed the 6L6 schematic cathode resistors (matches old parts list). Added printable board outline. Added FrontPanelExpress files. Still no ULtra notes. See my ULtra post until then.

Image
Last edited by Shannon Parks on Sat Aug 04, 2012 4:03 pm, edited 24 times in total.
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Postby Ty_Bower » Sat Aug 06, 2011 2:55 pm

I would add the RCA input jacks and speaker binding posts to my Mouser order. Mouser also sells Triad filter chokes. I'll go look up the part numbers for my favorites, and post them here.

Binding posts:
Kobiconn 164-19B2-EX, $3.68 per set

Triad filter choke:
C-24X, 1H, 50 ohm, $8.77 each

Alternate Triad chokes:
C-8X, 7H, 240 ohms, $9.86
C-7X, 10H, 270 ohms, $11.74
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Postby Shannon Parks » Sat Aug 06, 2011 5:47 pm

Ty_Bower wrote:I would add the RCA input jacks and speaker binding posts to my Mouser order. Mouser also sells Triad filter chokes. I'll go look up the part numbers for my favorites, and post them here.

Binding posts:
Kobiconn 164-19B2-EX, $3.68 per set

Triad filter choke:
C-24X, 1H, 50 ohm, $8.77 each

Alternate Triad chokes:
C-8X, 7H, 240 ohms, $9.86
C-7X, 10H, 270 ohms, $11.74


And all this looks good. I would just use a jumper at R21 (instead of 100 ohm, 3W) if I used the alternate, higher DCR & H Triad chokes.

Shannon
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Postby EWBrown » Sat Aug 06, 2011 9:24 pm

The other "unused" resistor and connector locations are for the 6L6 implementation, G2 stoppers, NFB loop, etc.

Kind of a "Swiss Army Knife" design, it has many functions O:) [:) (love)

/ed B in NC
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Postby Shannon Parks » Tue Sep 06, 2011 10:48 am

Added the following note concerning standard 6L6s with their 19W plate dissipation:

"If using a standard 19W rated 6L6, we want 680 ohms for the cathode bias instead of 500 ohms. Make R18 and R19 2.2K resistors (72-RWM410-2K2-5)."

My 500 ohms in the parts list (two 3W 1K resistors in parallel) was spec'd using an 807. 500 ohms should be good for all the tubes in that family: 6L6GCs, 807s, 1625s, and 6BG6s.

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Postby apurcell22 » Sun Sep 25, 2011 7:43 pm

I noticed the schematic for the 6L6 variant calls for 600V coupling caps and the bom has 400V. Is 400V sufficient?
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Postby Geek » Mon Sep 26, 2011 4:44 am

apurcell22 wrote:I noticed the schematic for the 6L6 variant calls for 600V coupling caps and the bom has 400V. Is 400V sufficient?
Al


No.

B+ plus Vp-p plus Vbias will easily toast a 400V unit, IMO.

Cheers!
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Postby Shannon Parks » Mon Sep 26, 2011 6:14 am

I just updated the Chubby Clementine BOMs:
- Changed the rectifiers to UF4007s
- Changed the 400V coupling caps to 600V
- Added a GE CL90 inrush current limiter

The coupling cap operates with 230V across it with AC voltage peaks (+/-50Vpp) up to 300V, but since we don't use a 5AR4, we have instant B+ and cold tubes with no voltage drops. Not a huge deal to use a 400V in there, but no reason to not switch to a 600V cap.

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Postby Shannon Parks » Mon Sep 26, 2011 9:01 am

Oh - I do need to spec new cathode resistors at R17, R18, R19 and R20. Right now I have 1K and 2.4K in each network, but I should probably balance it better.

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Postby apurcell22 » Mon Sep 26, 2011 9:18 am

All,
I have a couple of weeks before the Edcor power tranny gets here, so I will hold off on my parts order. I have some 400V auri caps here that I was thinking of using, is why I ask.
Thanks,
Al
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Postby EWBrown » Mon Sep 26, 2011 9:35 am

For the interstage coupling caps, the voltage ratings should be greater than the 6SL7 plate voltage which should be no greater than 300V at the signal peaks. The average or idling DC voltage across it should be around 200-240V, and add in the peak signal excursions which should be not much more than +/- 40V, above that, the amp would be getting into serious distortion and clipping.

Actually, I should have read Shannon's earlier reply, (before i jumped in here) which pretty much states the same thing, and he knows the actual voltages, I was just wagering a wild guess :))

If you put a 100K-300K 2-3W bleeder resistor across the last PSU filter cap, that would reduce the maximum the "cold tube" 6SL7 plate voltage somewhat. Sometimes I go "crazy" and put a bleeder across the first PSU cap, as well as the last / lowest voltage one. Cheap additional "insurance, in case a dropping resistor or choke should fail "open". O:)

I'd wager that the 400V Auricaps would be OK in the circuit.

The CL90 would also slow down the "cold tube" capacitor charging with SS rectifiers. Use a CL140 for the 1626 Darling version, and its lower AC input current demands.

If you are like me and can't leave "well enough" alone, try 12B4As, in place of 1626s (keeping all the same resistance values). and use the drilled out V2 and V3 socket approach, and wire in some 9 pin miniatures, or if you don't want to deface that nice looking board, just wire up the sockets to their octal equivalent locations



/ed B
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Postby apurcell22 » Mon Sep 26, 2011 9:42 am

Thanks Ed,
I have had them for a while. Got them in a trade with some other stuff. The 400V rating has kept me from using them in my recent projects.
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Postby miker » Sat Oct 15, 2011 8:41 am

Not sure if it has already been noted but, the voltage chart for the 1626 version shows 24V (cathode voltage) on pin 1 and 0V for pin 8. These two readings should be reversed, pin 8 is the cathode.

I just powered up my Clemy and reading 0 V on pin 1 (expecting 24 V) had me freaked out at first. Pictures to follow.
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Postby Shannon Parks » Mon Oct 17, 2011 12:06 pm

miker wrote:Not sure if it has already been noted but, the voltage chart for the 1626 version shows 24V (cathode voltage) on pin 1 and 0V for pin 8. These two readings should be reversed, pin 8 is the cathode.

I just powered up my Clemy and reading 0 V on pin 1 (expecting 24 V) had me freaked out at first. Pictures to follow.


Thanks for catching this. I'll get it updated.

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Postby badassbob » Fri Nov 11, 2011 8:31 am

Hey Shannon, what is the "hole pattern" on this board? Id love to do an FPE file for it ;)
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