Clementine confusion

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

Clementine confusion

Postby croudyj » Sun Apr 17, 2016 7:34 pm

Hi, I'm new here. I joined because I'm thinking about attempting to build a Clementine. I have a fair bit of electronics hobby experience but it's all low voltage stuff, mainly digital ICs. The only experience I have with tubes is a factory-made Fat Man iTube 252 that I owned when I lived in Europe. I enjoyed its sound and I miss it somewhat, so I thought I'd have a go at building something.

The Clementine seems like a good middle-ground between doing it all from scratch with just a schematic and getting a full kit of parts. I don't have the know-how to do any experimentation or modding so I'm hoping this will be a case of 'build it right and it will just work'. I'm thinking about trying the 6L6 version.

Although I have read every post that seems relevant, I still have a few questions (some of which may appear dumb but hey, I want to do this right):

1. What is a 'chubby' clementine? I don't see it mentioned in the Clementine Manual PDF.

2. Does it have to use plain 6L6s or can I use 6L6GCs or similar with no modifications?

3. I've been looking at the tubes on tubedepot.com and I see a wide variation in price. Is there a huge sonic benefit in paying more than $14 for a Sovtek or is this truly a case of 'you get what you pay for'?

4. The schematic does not include a volume control but I see some builds have one. I would like to do this too. I expect I can figure out where to connect it (voltage divider right at the input?) but I was wondering if there are any 'gotchas' or recommendations I should be aware of. I expect it would be trivial to also add an input selector switch. Apart from needing shielded cable, are there any caveats here?

5. Why does it use screw terminals instead of just soldering the wires directly to the board?

That's about it for now. Thanks in advance for any advice.

John
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Re: Clementine confusion

Postby TomMcNally » Sun Apr 17, 2016 8:41 pm

Hi and welcome to diytube ...

about the name ... the original 1626 amplifier was called "The Darling" so this one was dubbed "Clementine" as in Oh My Darling Clementine. Paying homage to an old and funny Bobby Darin song called Clementine about a 299 pound chubby chick we called the one with "fat" tubes a "Chubby Clementine"

https://www.youtube.com/watch?v=0UosSbCXTUw

You can use pretty much any 6L6 based tube with no changes, 6550, 5881, KT-66-77-88, EL-34 etc. Don't bother with KT-299's or anything extravagant, this is a low power amp !

I've built quite a few of these, and find the generic Russian tubes on eBay to be perfect at a low price.

a 100K volume control and A/B input switch is easy, there is plenty of info and pictures in the forums, use the search box

The screw terminals make it an easy build. The board can be removed easily. Oh - the power transformer center tap wire IS soldered.

My suggested steps:
1) before soldering anything to the board, use it as a template and mark the chassis with a Sharpie through the holes, including tube centers
and use your transformers as templates as well, drill holes for power connector, speaker terminals, RCA jacks, volume control, input switch
2) do the metalwork. tube sockets need 1 1/16" hole.
3) mount the parts
4) assemble the board and put it in place
5) connect the wires
6) listen to the results

Plenty of help here on the forum, lots of pictures on my web page at http://tmamps.com

... tom
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Re: Clementine confusion

Postby croudyj » Mon Apr 18, 2016 1:46 pm

Tom, thanks for your reply. I can't believe the number of amps you've built! I will certainly follow your expert advice.

The only thing that really concerns me now is the metalwork. I'm much better at soldering than I am with power tools. I'm thinking of using the 12 x 8 x 2 black steel Hammond chassis but I don't know how I'm going to make those large holes. I only have a battery powered hand drill. Is there some kind of special bit I can use or do I need to buy a whole new tool for punching steel?

Thanks again,

John
Last edited by croudyj on Sun Apr 24, 2016 12:16 am, edited 1 time in total.
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Re: Clementine confusion

Postby TomMcNally » Mon Apr 18, 2016 2:17 pm

Hi John -

Almost all of the amps on my web page were built on my kitchen counter using a battery powered hand drill. A drill press is slow and cumbersome.

But this before it gets away ... http://www.ebay.com/itm/Greenlee-1-1-16-Radio-Chassis-Actual-Diameter-Knockout-Punch-3279-80-/111916574067?hash=item1a0ebf6573:g:bgoAAOSwQYZWzzTP

Here's my method ...

Use the diytube PCB as a template, use a Silver Sharpie on a black chassis or black on silver ... put a dot in each hole, same for the transformers and jacks, etc
I use a Stanley "automatic Centerpunch" and ding every mark
use a small bit - 1/16" and drill all of the holes out
drill the board mounting holes out to the right size for 6-32 hardware (I don't remember !)
drill the transformer mounting holes out for 8-32 hardware
invest in a Unibit (brand name only - no Chinese) and enlarge the grommet holes 1/2 way across the transformer to 5/8"
drill 3/8" holes 1" apart for your RCA jacks using Unibit
drill 1/2" holes 3/4" apart for your speaker terminals (if you use the kind I use)
enlarge the tube socket pilot holes up to maybe 1/4" then carefully to 3/8" with the Unibit
use the new Greenlee punch and a socket and ratchet to punch the socket holes.
The hard part might be the IEC socket. I use a Dremel but it's not for the timid.

Clean it all up ... mount your stuff.

I've done a lot of chassis for guys, I'd be glad to help if you need it.

... tom
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Re: Clementine confusion

Postby croudyj » Mon Apr 18, 2016 4:05 pm

Thanks,Tom.

That Greenlee punch had me baffled for a while until I found a YouTube video showing how to use it. Pretty clever!

For the Unibit I found this:

http://www.homedepot.com/p/Unibit-Step- ... /100662385

I also saw one that goes up to 1 1/8 which is a tiny bit bigger than the required size, but it's expensive.

Thanks for your offer of help. Just a little guidance like this and I think I'll be able to manage it. I just need to understand exactly what tools I need. I do own a Dremel but it has a saw attachment for cutting wood. I expect I could get a smaller metal saw for that.

In the past, I have made large holes by drilling loads of small holes next to each other and then using a small file. Even in aluminium this was a nightmare!

Thanks...

John
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Re: Clementine confusion

Postby TomMcNally » Mon Apr 18, 2016 6:43 pm

That's the right Unibit ... expensive, but they make relatively clean holes, much better that a twist bit.

Actually the best thing for a Dremel is a fiber disk made by Gyros 1 3/4" diameter, 1/8 hole, 1/32" thick. First time you'll need their Mandrel kit. Cheap and long lasting. I just mark the rectangular hole for the IEC and a few minutes later have a perfect hole. Lots of harmless sparks are fun.

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Re: Clementine confusion

Postby croudyj » Tue Apr 19, 2016 10:51 am

Wow! Sparks like that are scary. I find my Dremel very intimidating even when using it on wood. I'm thinking of trying to make this thing look very retro and I remember that back in the day they didn't even have power sockets, just a fixed cord with a plug on the end. In the UK you even had to buy the plug separately and put it on yourself.

Well, yesterday I ordered that punch and the Clementine PCB, which Shannon kindly shipped about 20 minutes ago! Unfortunately the Edcor site has been down for a few days. Rather frustrating as they're the parts that are going to take the longest to ship and I wanted to get them ordered. They give no indication at all about when they'll be back and you can't even browse stuff. Still, this just gives me extra time to plan and carefully choose other parts.

Thanks again, Tom. Your huge list of amps is a great inspiration and gives more than enough clues about how to do the layout properly. I'm excited to think that I might be able to make a good amp for a quarter of what I paid for my iTube 252 and with much higher quality. That thing sounded great but the volume control pot failed after 8 months and I had to replace it. Later the amp developed a weird crackling problem. Cheap -- yet expensive.

John
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Re: Clementine confusion

Postby TomMcNally » Tue Apr 19, 2016 1:34 pm

It's easy enough to hard wire a power cord, I just like the convenience of the combination fuse/IEC connector.

I was just on Edcor ... I don't see a problem https://www.edcorusa.com/ ?

There are some substitutes on the Mouser parts list too, but you have plenty of time for that while you wait for transformers.

I have two sets on order from Edcor, one for a Chubby Clementine and one for a Darling style.
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Re: Clementine confusion

Postby croudyj » Tue Apr 19, 2016 1:54 pm

Hi Tom,

You say you can get to Edcor's site right now? That's really weird. I am still seeing a page that says "This store is currently closed. Please check back shortly. We are in the process of updating our system. Sorry for any inconvenience." It's been like that for a couple of days now. It doesn't matter what I try, I just keep getting redirected to https://www.edcorusa.com/storeclosed

Aha... I just found this:

https://twitter.com/edcorusa

So something is up...

John
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Re: Clementine confusion

Postby TomMcNally » Tue Apr 19, 2016 2:19 pm

I actually logged into my account and checked on the status of my order.

I would try clearing your cache ... maybe you are being directed to the old (or new) site ???

I use the program CCleaner (Crap Cleaner) every day here at work, so maybe that's it.

You can always call them at (800) 854-0259 since you have the part numbers.

... tom
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Re: Clementine confusion

Postby Geek » Tue Apr 19, 2016 2:26 pm

Web hosts worldwide have been hit by various problems taking down millions of sites for various reasons (not attack, looks like plain bad luck according to Webhostingtalk) (n)
-= Gregg =-
Fine wine comes in glass bottles, not plastic sacks. Therefore the finer electrons are also found in glass bottles.
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Re: Clementine confusion

Postby croudyj » Tue Apr 19, 2016 3:31 pm

Hi Tom,

I did try clearing my cache and a different browser too. I think I just guessed what it might be. If they changed their web host, their IP address will have changed. It will take time for the DNS info to trickle through to all locations. When that happens you get a kind of split for a while where some people can see the site and others can't. So yes, I believe I'm looking at the old site and you're looking at the new one. Whatever, I'm sure it will be sorted out soon. What's another day when you have to wait 6 weeks anyway? If's it's not back by tomorrow morning I'll order by phone.

John
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Re: Clementine confusion

Postby croudyj » Thu Apr 21, 2016 3:23 pm

Well... the Edcor site reappeared yesterday and I've ordered the three transformers. I'm off to Home Depot at the weekend... $)

Thanks again,

John
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Re: Clementine confusion

Postby croudyj » Thu Apr 21, 2016 4:11 pm

And... the PCB just arrived! Thanks Shannon, it looks really nice. I'm really excited about this project!

John
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Re: Clementine confusion

Postby TomMcNally » Thu Apr 21, 2016 5:54 pm

I received a Mouser order today and assembled a Clementine board that I'm waiting on transformers for. Looking forward to it also.
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