5B6 started

[Reeltarded]

So you don't want to believe me, but you'll take some random guy on an internet forum's word for it?

He said this other guy was an expert. Sheesh.

[M Fowler]

Went over the wires again and checked the fuse...
One side of the IEC goes to the fuse, then to the "on/off" switch, then from the other side of the "on/off" switch through the transformer, and into the other side of the IEC.

From Load (L) of IEC to fuse holder, then to power switch, then to one of the AC black primary PT wires.

IEC Earth (E) to stand alone chassis ground.

IEC Neutral (N) connect PT's other black wire here. I like to slip a white shrink tube on it for marking it as neutral for USA.

Mark

[telentubes]

Thanks Mark,
Worded differently but I've done the same thing as you described. I will go back in this morning and have another look.

[M Fowler]

Good then we can try figure out other problem areas.

[telentubes]

Found it. Filament short. Voltages look good up to the 6SC7.

Now I need to work on the input section. High voltage on the 6SC7 and possibly no signal. I may have wired the jacks and B+ incorrectly as the octal preamp is new to me. Thanks Mark!

[telentubes]

Fired up the amp after replacing the alleged NOS Haltron 6SC7 preamp tube, which turned out to be DOA and the reason why the voltages were double what they should have been on V1.
The back-up I got is an RCA metal jacket, and although the amp has some nice tones and natural compression, the tube is microphonic and kinda hissy. I understand that that is a common problem with those tubes, and it may take a few trys to find a good one, but worth it when you do. I like the amp and will leave it on most of tomorrow to let it cook and burn in, then take it from there.
Voltage chart
B+... 413V, 358V, 341V
V1 pin 2,5... 149V, pin 6... 1,9V
V2 pin 2,5... 201V, pin 6... 2.4V
V3/V4 pin 3... 409V, pin4... 358V, pin 8... 28V
5U4 pin 2,8... 413V, pin 4,6... 356V

[telentubes]

So, after playing for a while and turning up the volume a bit, I guess I don't like this amp as much as I thought. Couldn't find that creamy overdrive that Mark was talking about in his cage amp, and the bass notes sound like a wounded animal when leaned on, and there is some ice picky treble that is hard to take.
l got some new Sovtek 6SC7s and I like them a lot. Very quiet. Also replaced the NOS with another, and it is also good.

Then I went back in to mess with the voltages, which has made a huge difference.

1st 10K dropping resistor changed to a 22K.
270K plate resistors on V1 and V2 replaced with 180K
Tried a 68K grid stopper and took it out.

The new voltages resulted in a lot cleaner amp, with more head room. Voltages on Tino's schematic in parentheses.

B+ 415 (400), 313 (320), 295 (300)
6SC7 plate 155 (160), cathode 2.1 (2)
6SL7 plates 205 (216), cathodes 2.4 (2.5)
6L6s, pin 3... 414 (390), pin 4... 313 (320), pin 8... 23 (25)

I still need to knock down the treble a little.
A Celestion Vin 30 8 ohm speaker is the best so far.

[Blackburn]

Nice clean build, Telentubes. Interesting that you mentioned getting a Haltron 6SC7 DOA in the mail. I had the same experience with the first one I got from TD. The vacuum had been breached in that one. The second one turned out fine. I also had a bit of the same issue with sharp high end in my 5B6, when it was around. I also changed my power string around (Especially the preamp) and knocked voltages up a good bit. Pretty cool amps and dirty tone that is kinda cool. I think you should try playing it through a nice AlNiCo speaker. I was running mine with an ASW Elegante and liked that configuration quite a bit. Looking forward to seeing your progress as you go.

[M Fowler]

My last 50w version has been an absolute bitch to enjoy as well

[telentubes]

Do you think I need to raise the value of the cathode resistor on the 6l6s, or is the 250 Ohm OK?

[M Fowler]

Your voltages are so close to Tino's it should be about right now.

Might increase bias to 270R or 300R

My cage amp is quite a different amp then the other's I've built and the cage amp still is the best sounding. I didn't change any of the values that Tino listed when I built the cage amp. It uses cheap IC caps, CF resistors, PTP construction, Weber can cap, Weber OT, and Weber PT. The owner enjoys the amp and so did my friends and I. Plan to build some more PTP versions and no more tone board versions. Also, going to use Weber iron too. Maybe the key element is to use under rated iron?

[telentubes]

Thanks Mark,
I've used Weber iron in a few amps, and they have turned out well. Also built with a mismash of parts that were left-overs, mismatched and cheap, also with good results.

This 5B6 has taken a LOT of time to dial in, but I think I'm getting there.

Blackburn, I have a Celestion Blue and Weber Blue alnicos around that I will try (I sold the Gold). The Weber has a high enough power rating so I wouldn't worry about it.

[telentubes]

Cab finished today. I may have gone a little overboard on the "aging" of the tweed, but it's growing on me.
I will probably use a Celestion Vintage 30 speaker, and not the one pictured. I took out the Vin 30 and stuck it in my BFPR. I like it in the Princeton.
Oh, and yeah, it needs a leather handle. I just used what I had left in the drawer.

[M Fowler]

That is a sweet looking amp.

[telentubes]

Thanks Mark. Cathode resistors should be arriving today. Still doing some tweaking on tone, voltages, etc, but getting there.