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nikolas812 14th February 2009 04:20 AM

Simple SE with KT88's
I just bought a bare PC board from the Tube Lab. At least I think I did? I sent the money via paypal using his email address. I assumed this was his paypal ID. I've yet to here back from him... But I did just send the money this morning.......

I have absolutely know idea what i am doing. I just thought it would be fun to try and build a tube amp with the parts I want to use...

I have been reading at the Tubelab website for a few hours straight now. And I feel fairly confident I can build the amp. The Details and instructions are very good and seem fairly simple to follow.. Except for the Power side of things..

So I have pretty much sourced all of my parts except for.

Output Transformer ( I need two)
Power Transformer
Power Choke
Auxiliary power supply cap

I am wanting to run KT88's with 8ohm speakers

But I have no idea what to buy for the power side or if it. I am totally lost.

I just bought the board today so it probably won't even be here for week so I guess.......

But am trying to source all of my parts so I can get an idea of total money involved in the project..

So if anybody can point me in the right direction for the items listed it would be appreciated.. If I can figure out the correct ones to get I believe I would be able to bring the amp to 100% once I get all the parts. I just need to make sure I get the correct ones.

Many thanks in advance for any help and please be kind.. I'm a total newb when it come to this stuff. So please speaker slowly. :)


Ty_Bower 14th February 2009 04:32 AM

Simple SE is a very fine amp, and it loves KT88 tubes. If you're going to run the big tubes, shoot for voltage at the top of the range - a power transformer rated for 750VCT is ideal. I used a Hammond 374BX on mine. I wrote a long thread while I was building it. You'll fine it here.

rkevans 14th February 2009 06:50 AM

You're going to enjoy this amp !!!
1. The CEO, President, Senior VP and janitor of (just kidding, it's a one man company) are in Orlando for the weekend selling part of his collection of tubes at a ham fest. He's pretty good about shipping quickly, but I suspect he's away from email for a moment.

2. The Simple SE was my first tube amp (and the only one so far). You're really going to having fun building it!

3. The majority of them have been built with Hammond 274BX power transformers or the Allied 6K7VG (cheaper and suspected to be an OEM version of the 274BX). I used the Allied one after George mentioned it a few times. There are rumors that some 200-series transformers may 'buzz' and the 300-series (international version, 120/240 VAC input) is quieter/more rugged. My Allied doesn't buzz. My B+ voltage has always been a little on the high side, and I think I might drop down to a 700 VCT tranny if I ever build my second board (ordered as a spare but ...). Somebody (chrish ???) has custom-ordered a power tranny from Edcor too, and it's available w/o the $20 fee if you ask for model XPWR059 (not on the website).

4. Output transformers in order of increasing cost:

(Great value, might be a little bass-shy)
Edcor XSE15-8-5K $20 ea
Edcor GXSE15-8-5K $31 ea

(Getting better)
Transcendar SE w/ UL taps $50-ish ea (Ebay)

(Beginning of the 'Serious' stuff)
Edcor CXSE25-8-5K $83.50 ea
Magnequest Robin Hood $100 ea
Hammond 1628SEA $129 ea

(Boutique Stuff)
I didn't shop in this price range...

No advice here. I got the GXSE ones and have no complaints, but I've also never used them w/ the big KT88 tubes, either... The XSE is pretty popular in the "make it work, I'll get better ones later" category.

5. You don't NEED a choke and aux cap to build it. I added a Hammond P-T193H (5H, 200 mA, $30) choke after a week and it was actually a subtle decrease in noise.

6. For an aux cap, walk into any HVAC supply store and ask for a Motor RUN cap with a 370 VAC (or 440 VAC) rating. They have boxes full of them... 80 uF seems like a common 'big' size. They're also easy to get from Ebay.


nikolas812 14th February 2009 04:07 PM

Thanks for the replies.

I have been reading all the Simple SE Threads like a mad man. :)

I just wanted to start my own thread so it could be follwed, documented and so I could get help from you guys along the way. I'm sure I'll need it.

I also wanted to ask about the the related resitors and capacitors.

I was thinking about sourcing all of these from some place like Sonicraft. And going with all high end parts... What do you think?

Or would I be better off going with the digi key stuff for $40.00 and just get a couple high end capcitors ( the ones Digi doesn't have. the .22uf caps)????

So for the power side I am looking at

Hammond 374BX
Hammond P-T159Q choke
Transcendar SE 5K, 8 ohm, 10 watt x 2
80 mfd 500 VAC Motor Run CapSourced Here

Woudl this work? Is this what you have TY?

I am pretty much looking for a proven setup for KT88's that I can put together and know it will work.. And I want soemthing decent but won't break the bank. Ty's setup looks the best so far... So that is what I am pretty much following... At least for the power side of things..

Also I know I don't need the choke to get the amp to work. But I don't want to just get the amp to work. I would like it to work well and to my likeing.. Hence the choke just for peace of mind..

Also want to ask about the Freds. I see many people haveing problems with them. Is something I need. Or is something I could leave out? Just trying to forsee and future problems and take care of them before hand..



rkevans 14th February 2009 05:00 PM

There's no reason NOT to build it with the best parts you feel comfortable buying. Having said that, the 0.22 uF coupling caps are probably the first place I'd look for an upgrade.

That choke looks a little small ( 150 mA rating ). Consider matching the rating of your power tranny (200 mA) and going to an enclosed model to match the appearance of the other Hammond part -- they look nice together.

I'd suggest buying the FRED diodes and not installing them. Recent batches of 5AR4/GZ34 rectifiers seem to have a high failure rate (it happened to me). If your rectifier blows, you can install the 'backup' diodes while you wait for a new part to arrive.

It's not in the parts list, but you might also look at adding an in-rush current limiter ( to the input (115V) side of the power transformer... It's been mentioned in the forums (by George, even).


Ty_Bower 14th February 2009 05:35 PM


Originally posted by rkevans
I'd suggest buying the FRED diodes and not installing them.
I've seen too many recent reports of failed IXYS diodes in Simple SE amps. I'd consider getting the Fairchild substitute (part number ISL9R8120P2) that George suggested here:

nikolas812 14th February 2009 08:32 PM


That choke looks a little small ( 150 mA rating ). Consider matching the rating of your power tranny (200 mA) and going to an enclosed model to match the appearance of the other Hammond part -- they look nice together.

Could you point the correct one out for me? Maby a model number or a link?

I hated the way that silver can looked from the get go. I much prefer soemthing easier on the eyes AND better suited for the application.

I'll contact Sonic craft and see if they can fill out the parts list and see what the difference is. If its not too terribly much I will go with the better parts.... That was the main reason for me wanting to do a amp project from the ground up. Being able to put high end parts in the amp was a big seller to me. I figure instead of buying a amp kit and getting sub par parts. I could buy the boards and build a better amp with better parts for about the same money.

I am getting very excited and it looks I am getting close to being ready to buy the parts..

I have already cleared out a room in the house dedicated to building this amp. I just need to get the parts...

I think I might be looking forward to building the chassis the most though. My dad owns a body shop that I have been working at for most of my life. So I have a feeling I can make a pretty immpressive chassis for it.

I have already redone a Jolida Chassis with good results. The only difference is this one will be from the ground up and not from a previous chassis..

Heres a pic of the Jolida I modded..



Theres also a website here with a few words on it and some more pics..

Artillery of Sound

boywonder 14th February 2009 09:20 PM

How did you do the graphics on the Jolida?

Ty_Bower 14th February 2009 09:27 PM


Originally posted by nikolas812
Could you point the correct one out for me? Maby a model number or a link?
I assume you are asking for an enclosed Hammond filter choke? The P-T193J is probably the one you want.

nikolas812 14th February 2009 09:59 PM


Originally posted by boywonder
How did you do the graphics on the Jolida?


Originally posted by Ty_Bower

I assume you are asking for an enclosed Hammond filter choke? The P-T193J is probably the one you want.

I did the Jolida with stickers I found on the internet. I thought it might look cheap with stickers. But it actually turned out really well and was a nice finishing touch. The next one I do I will apply the stickers after I apply the base coat. Then clear over top of them..

Yes I was asking about the encloesed Hammond choke. I thought he was talking about the cap at first. I actually found the same model you pointed out to me. I posted my find in a previous post. But I guess it still hasn't hit the thread yet.

I also emailed Sonicraft my parts list and I am waiting for a total.

I also just ordered some Sovtek KT88's, a Sovtek 5AR4, JJ 12at7 and the tube sockets. I might go with some NOS tubes later down the road. But these were the cheapest I could find to get the amp going..

I am going to look into ordering the power side of things while I wait for Sonicraft to get back to me..

Can anybody recommend a good soldering station that won't break the bank? I was looking at this one from Amazon.


Thanks again for the help.


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