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Discussion in 'The Squawk Box' started by TWANG, Jun 29, 2010.
It's a quiet as my amp here!! Lol
I think you might have a mismatch on the other side of the transformer.
R12 is on the HV line.
Are u sure that the attenuator is properly matched?
If it isn't and you crank it a lot, then R12 blowing seems logic to me. As in too high voltages/load and it is first in line, probably why it blew.
Might also be that transformer has been used unloaded / 0 resistance.
You could PM Twang, but that requires over 50 posts or something like that.
Can't recall, but you need a lot of posts.
I'll PM him for you.
It's odd. The tube cube acts to match your amp to your cab, I definitely had the speaker cable in the correct speaker socket and it was matched on the attenuator. Sorry, you may have to explain a mismatch on the other side of the transformer for me! I really appreciate the guidance, thanks so much.
I gotta dig out my schematic.. been too long.
They have some R in there that are undervalued.. like 2W where it really needs 5W.
There's a diode in there that doesn't do anything but die and kill the amp, but I don't
think this is related. I'll come back with it's number, you just take it out, don't even jumper it.
I don't know the tube cube so any problem there I'm at a loss to reply to.
Thank you so much! Very appreciated.
haven't forgotten.. just totally pressed for time.
I'll try to get to this tomorrow..
there are a lot of pics here.. one of these urls should lead you to the album..
just for in the meantime
Kustom No. 3 Photo by TWANGthang | Photobucket
http://i239.photobucket.com/albums/ff83/TWANGthang/Kustom Defender 5H/kustom004-1.jpg
in this pic just below the green resistor in the middle you'll see the little black diode..
pull that thing out
and add one of these.. much bigger better tone..
hi i'm new of this forum and i'm from italy. i've bought today the kustom defender 5h reading this post and i like to do some mods. i'd like to add tone stack and change tubes and ot. i have a spare hammond 125cse, could it do the trick? it's 8 watt single ended output transformer. in italy aren't available classic tone transformers. thanks in advance and sorry for my not so good english
I have a defender v15. If anyone with some knowledge of tube amp circuits could give a quick look at the schematic, I believe that mods would be similar to those that were discovered and implemented here on the 5H head.
Please have a look here http://www.mylespaul.com/forums/squawk-box/290680-kustom-v15-mods.html
Schematic is attached to first post
The tonestack part should be somewhere in this thread. Go back a few pages.
(BTW a full tonestack would take some of the gain that is on tap)
You might want to start simple, standby switch is easy and efficient for the tube life.
I've taken a look at the specs of the 125CSE - as far as I can tell, this would make a fine upgrade indeed.
Have you tried swapping the tubes? I like a 12AT7 as pre.
thanks syrus, glad i am not alone. for the moment i swapped only the ecc83 for an old nos philips mini watt ecc83 but i have also an electro harmonix 12at7 to test. i am searching pre gain in this amp because it's very loud for a 5 watter and believe me with my band in clean mode and with a distortion pedal i can compete with my drummer. i have owned in the past a marshall class 5 but this little fellow it's more loud. my board is a revision E without the nasty diode in d7. i'd like to add tone stack for tonal versatility and i have absolutely to change c4 and c 5 to something in the marshall vein, 0,68 uf, to have a tight bass with amp overdrive. this little kustom for an amp with only two gain stage has a lot of overdrive and i like it. even metal sounds pushed with my cheap behringer eq 700. i have put down the first two sliders (100 and 200 hz) and up the master
thanks to all for the information on the Kustom Defender 5h.
So far I figured the easiest mods/todo's are - please correct:
Prep: Turn off the amp, discharge the condensators rated up to 500v. (I would use my DC Multimeter on 600v setting)
1 "Problem solver":
Get rid of d7. Just cutting it out - nothing more (P.S.: Mine does not have the d7 in it. I own Revision D/Schematics show B)
2 Master Volume:
Just desolder R8 and then solder two wires in the holes. One goes to an outside lead and the other to the middle lead on a 250k/500k pot. Then I soldered in a wire on the other lead and attached it to the chassis to ground it.
Same as above with R17
4 Standby Switch:
The "green wire" to the PCD interrupted by a switch. It rates at 280VAC 50ma. I can only find 250V switches - are they safe to use?
Thanks for all the input. Please correct anything wrong.
Hi, all. First I would like to thank everyone for all the great info on this little amp. I already fitted the standby switch and volume pot following the information in this thread.
Now I wanted to add the 3way tone stack, but the website leroybeal.net is down? I can't get the pictures and schematics you mention. Does maybe someone has some pictures from this website and could you attach then to this thread?
From what I could understand only from conversation, the 3way tonestack is fitted instead the C2? So I remove the C2 and fit wires in the holes instead? I don't know there the wires go. And the R17 would be only useful for the brightness?
@Achilles' Heel thank you for the photos of the pots. Could you maybe post a photo from where on the board the wires go to the pots? That would be really the key to what I'm missing.
Thank you all!