Simple SE with KT88's

[nikolas812]

Take your time, read and re-read the labels, data sheets, etc. and keep asking questions.

Thanks. I have been reading like crazy for days and days.


And trust me. There will be no shortage of questions.😀





Nick

 

[pchw]

Nick,

Where is the fuse? Make sure there is one between the hot wire from the IEC and the switch.

 

[Tubelab_com]

Where is the fuse? Make sure there is one between the hot wire from the IEC and the switch.

I have it hooked up to a fuesed IEC socket and the Power Transformer

There is a fuse inside the IEC. I use these too it saves one hole in the chassis.

 

[pchw]

There is a fuse inside the IEC. I use these too it saves one hole in the chassis.

LOL, that's why I never do anything serious after a long work day

A question for you, George. Is 2.5K primary too low for the SSE? Or, it is better to save them for Tubelab SE later? These are Hammond 1627SEA.

Thanks!!

 

[nikolas812]

I think my OPT's might be arriveing today. So...


I need to know something.. Cathode feedback or NO Cathode Feedback?


I'll be setting up the amp intialy on a bread board wired for triode only with a choke and a motor run cap.

After everything looks to be running good I will be adding a UL switch and have the amp wired for Triode/UL operation.


So I need to know weather or not I should use Cathode feedback or not. I don't know what the difference is between the two.



Thanks



Nick

 

[Ty_Bower]

Start with no cathode feedback. It makes the wiring just a tiny bit easier. If you want, you can add it later after you have the amp working.

 

[nikolas812]

Thanks.


Thats what I was leaning towards. Looks a little easier wiring wise.








Nick

 

[Tubelab_com]

Start with no cathode feedback. It makes the wiring just a tiny bit easier.

I usually start with no feedback triode mode. The wiring for UL is similar so triode is just my preference since some OPT's don't do UL, I always start from the same configuration.

Is 2.5K primary too low for the SSE?

I could never get a 3 K OPT to sound as good as a 5K OPT with 400+ volts of B+. I have been using my 3K Transcendars with the 8 ohm load on the 4 ohm tap to give the tube a 6K load in the Simple SE with the Allied 6K7VG transformer. A 2.5 K load would work with a big tube (KT88) and a lower B+ like about 340 to 360 volts.

 

[nikolas812]

Alright folks.. I'm ready to fire up my amp and I am as nervous as I could be..


What should I do?

Should I leave the tubes out and check the board with mulitmeters?

If so. Where should I probe and what numbers should
I be looking for?

Also I'll need to know what connections are AC or DC..

And how to connect them. Is there a common ground on the chassis that I can connect the gound on the volt meter to?

I have alligator clips to use so I don't have to go probing around the amp unless I have too.



Or should I just stick the tubes in fire it up and see if it works...



Nick

 

[korneluk]

Nick,

Please follow George's tips on:

Checkout
http://www.tubelab.com/AssemblyManualSimpleSE/Checkout_SSE.htm

and safe meter usage
http://www.tubelab.com/AssemblyManualSimpleSE/MeterUse_SSE.htm

Alright folks.. I'm ready to fire up my amp and I am as nervous as I could be..
Also I'll need to know what connections are AC or DC..

Everything before the rectifier is AC, everything after the rectifier is DC.

Also, do not use your good speakers to test the amp for the first time - just in case. Either use a dummy load, or a junky pair of speakers.

 

[nikolas812]

Thanks but not exactly what I am looking for...


So anywhoo..


I turned the amplifier on without tubes. I can't get a reading on anything anywhere except the T1-Red. T1- Yellow reads nothing. The B+ going to the OPTs reads nothing. C1 reads nothing...

I am getting nothing on the board except T1-red which reads 425volts with no tubes.


Put the tubes in the and 12at7 and 5ar4 start to light up and then the fuse blows.


So this is where I am as of right now.🙁




Nick

 

[korneluk]

I turned the amplifier on without tubes. I can't get a reading on anything anywhere except the T1-Red. T1- Yellow reads nothing. The B+ going to the OPTs reads nothing. C1 reads nothing...

I am getting nothing on the board except T1-red which reads 425volts with no tubes.

Sure, without the rectifier tube, there will be no B+, so you will only read the AC on the secondary of the transformer.

Put the tubes in the and 12at7 and 5ar4 start to light up and then the fuse blows.

When the rectifier starts to warm up and conduct, the B+ will slowly rise and then the fuse will blow - I suspect you have a solder short or a misplaced wire somewhere.

Take your ohm-meter and, WITH THE POWER OFF AND the MOTOR RUN CAP DISCHARGED, measure between B+ and ground, make sure you do not have a short.

Another quick check is to make sure you installed the 10M45 ICs correctly.

 

[nikolas812]

Take your ohm-meter and, WITH THE POWER OFF AND the MOTOR RUN CAP DISCHARGED, measure between B+ and ground, make sure you do not have a short.

Can you explain to me how to do this as if you were telling a 5 year old?


I have a Fluke 29 but I be damned if I know how to work it...



I feel like I might have taken on too much.



Nick

 

[nikolas812]

Heres a couple pics.

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[korneluk]

how about the underside of the PCB? Just making sure you did not reverse the 10M45 when you installed it from the bottom.

Thx,

 

[nikolas812]

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[korneluk]

Nick,

For checkout, you do not need the inputs (and the volume pot) connected.

Can you please remove the heatsinks from the 10M45s and verify you did not flip them when you installed them on the bottom?

Thx,

 

[wicked1]

Cost?

Do you know how much money you have invested in this amp?

 

[nikolas812]

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[nikolas812]

Re: Cost?

Do you know how much money you have invested in this amp?

$700.00









Nick