My Simple SE via Akihabara

[bigjppop]

So I'm just getting turned on to this DIY audio thing and am really excited to get my feet wet. I've been a tube fan for quite some time but I've been limited to tube amps in my headphone rig. Now its time for some speakers.

So I'm still in the early planning stages and have a general question that will help me finalize my budget. Will I get any benefit from building a preamp? I only use one source (an Oppo universal player for now) and really only need volume control. Will simply adding a volume pot to the Simple SE get me where I want to go? Will I get better/worse wound buy adding something like a Bottlehead Foreplay III to the mix? I'd love to figure out someway to get a remote volume control but that will probably be down the road. Anyway, whether or not I need a preamp will determine how much dough I have for the Simple SE.

Also of note, I'm trying to buy as much of my stuff as I can in Akihabara (I live in Tokyo) but can order what I need from the States via Uncle Sam and the APO mail system. I'm going to do my first recon trip through Akihabara on Friday to see if its going to be cheaper to buy online and ship or buy here. Often times, its cheaper to buy even Japanese made stuff in the US and then ship it here rather than buy on the economy. Strange, I know.

Anyway, I love this place and can't believe how helpful everyone is here. I'm hoping this will become a life long hobby. I'm sure I'll be back with a million more questions, but setting a budget is #1.

Jeremy

OK, first question. I live on a US military base here so we have 110 power. I'm going to be moving to Berlin in Jan so I would love to set this amp up so that its an easy switch to 240V when I get there. Can anybody recommend a good power transformer that will let me switch my mains? I've heard this is pretty easy to do, anyone have any experience?

[tubelab.com]

Will I get any benefit from building a preamp?

Not much. Some builders claim that a preamp or a line stage enhances the tube sound, but it is not needed if you are using a CD or DVD player for a source. Some type of preamp that includes a phono stage is required if you are using a turntable.

Will simply adding a volume pot to the Simple SE get me where I want to go?

Yes, for now. There are remote controled volume controls out there. GoldPoint has shown one in their magazine ads but it isn't on their web site yet. A friend of mine got one from China on Ebay. You can use a good quality pot for now and swap it out later.

OK, first question. I live on a US military base here so we have 110 power. I'm going to be moving to Berlin in Jan so I would love to set this amp up so that its an easy switch to 240V when I get there. Can anybody recommend a good power transformer that will let me switch my mains?

Most non US builders use a Hammond 374BX power transformer. It will work anywhere in the world. The voltage choice is changed by using a different combination of input wiring, so don't cut any wires. Just tape up the ones not used on 110 volts, because you will need them for 240 volts.

Question from another thread:

Just wondering where everyone gets those cool layout charts for cutting out the plate/chassis holes for there amps?

You can print the silkscreen layer of the PC board (its on the web site), tape it to the chassis, and use it for a drilling template for the PCB mounting and tube socket holes. Just make sure that the print out is exactly the same size as the PC board. You may need to adjust the scale factor on the PDF print.

I use Microsoft Visio (not free or even cheap) to lay out chassis. Some people use Powerpoint (again not free). I have seen people use Turbo Cad (not free, but cheap). I am sure that there is something free out there.

I will send your board on my next trip to the post office, probably Friday.

[rknize]

As long as your player has enough gain (can output "line level", around 2V RMS) and reasonable output impedance (should be fine from SS gear), there is no need for a preamp. Less is more. If you don't want to put a pot on the Simple SE, you can build a passive switchbox/volume control...an unamp. The Simple SE has plenty of gain, so even if your player falls a little short, you won't be left wanting.

[ttan98]

Tubelab,

I cannot send you a private mail from this site, my query is about your PP EL84 using LED bias.
Would you be able to email me a copy of the circuitry? thanks. send to tean_tan@hotmail.com.

[rknize]

Originally posted by tubelab.com
I use Microsoft Visio (not free or even cheap) to lay out chassis. Some people use Powerpoint (again not free). I have seen people use Turbo Cad (not free, but cheap). I am sure that there is something free out there.

I also use Visio for chassis layout, but once you use it you are stuck. Their file format is horrid, so no other application supports it well or at all. You can export as SVG, but the result is not really editable or otherwise useful. Other alternatives include:

- Inkscape - open source, powerful enough but a little tedious for things like layout diagrams. Something about the rulers and snap grid was giving me fits. Stores natively as SVG.

- OpenOffice Draw - a watered-down Visio clone. Perfectly fine for layouts. Stores files in an OpenDocument format.

[chrish]

I too have been looking at something for chassis layouts. I have been experimenting with google sketchup. Have found it to be quite simple to use and gives a good 3D representation of how your parts are going to fit together. Here is an example of the layout of a Push Pull 6L6 amp with mosfet source followers I am about to build (from design idea and help from Tubelab!). Design is not yet complete, but you will get the idea...

BTW, you will love the Simple SE! Other choices for power transformer are from Edcor. They make a transformer XPWR059 that has the same specification as teh Hammond mentioned by Tubelab. They are well regarded and cheap. They also make very good value for money output transformers, several builders of this amp (including myself) have been happy with them. I believe that you get your shipping through the US military system so don't have to pay the regular overseas shipping charges? If this is the case I would be very surprised if you found better value in Tokyo. Akihabara is definitely worth going to look at, I think there is a little market/bazaar with electronics stuff right next to the train station, but I think you will find ordering from the States cheaper.

Have fun with the build!

Chris

[chrish]

Another view

[bigjppop]

Thanks for the suggestions. I'll try them all and see what works. I just realized that I have Adobe Illustrator (never use it, it came bundled with Photoshop) and that might be able to work as well. I pretty much just want a template so I can get the holes cut in the right spots on the chassis plate.

My first recon trip through Akihabara is tomorrow so I'll see how things like value wise. I do ship cheap through the military system so that's always an option.

You guys are great and I appreciate all the help so far!

[bigjppop]

So I'm pretty sure I've nailed down my transformers, just want a sanity check before spending the bulk of my parts budget.

PWT: Edcor XPWR059
http://www.edcorusa.com/Products/Sho...ct.aspx?ID=632
I like the Universal aspect because I move a lot and want my amp to work everywhere.

OPT: Edcor CXSE25-8-5K
http://www.edcorusa.com/Products/Sho...ct.aspx?ID=465
I've got a couple of pairs of speakers I want to try with these, some 6 ohm and some 8 ohm. I'd like multiple secondaries but that doesn't seem to be an option here.

Also, I'd like to have the option for Ultra Linear but don't see that spelled out on the Edcor site. Does anyone know if it will be possible with these transformers?

Oh yes, I want to have the option for the full range of tubes here, including rectifiers; are these transformers going to allow that?

[kevinkr]

I'd think you would at least want to look at Japanese OPTs and spend some time in Akihabara - my experience with Japanese OPTs is that they can be better than most items available here. Check out recent issues of MJ to figure out what is available and where. I also understand you can haggle. You'll find some items that are available almost nowhere else. Look for Hashimoto, and there are also several brands that have not made it here, unfortunately a quick perusal of some back issues of MJ did not turn up what I was looking for. (I don't speak Japanese but I suspect you are in a better position than I am wrt to that issue.)

Try to find some English speaking Japanese hobbyists - I think you will find it worthwhile on many levels.

My dream is to someday shop the Akihabara market and visit some Japanese audiophiles. (Lately I am a fan of Japanese approach to tube audio.)