Weber OT gave in, new one swapable?

[Oddvar]

Hi.  My Weber Ot just gave in and I blught a new one from Classic Tone, it's rated at 50/60 watts, and I was wondering if it is swapable without any modifications to the build?  The new one is 4/8/16 ohm, 4.2 k ohm,



Thanks.

[sluckey]

I was wondering if it is swapable without any modifications to the build?

Which build? Which tubes? Got a schematic?

[Oddvar]

It's the weber 5f6a layout http://www.tedweber.com/media/kits/5f6a_layout.jpg

[sluckey]

The Weber WO22855 transformer only has a 2Ω speaker tap which is fine for the 5F6A amp. Your classic tone transformer does not have a 2Ω tap and is not a good replacement.

[Oddvar]

Hi and thanks again.

I bought the Classic Tone 40-18001 as a replacement for the Weber W041318.  The difference is the first one has 4.2k ohm primary and 4/8/16 ohm speaker output, the other has 6600 ohms and 8 ohm output.  I bought the Classi Tone from Ampparts Direct and Rick there said it was just to mount.  I did, and no sound whatsoever. 

[Oddvar]

Now there is a indication of sound just as I plugin the speakerjack.  Makes me wonder if I have connected the speakerjacks wrong.  Anyone with an idea on the proper way to change from just 8 Ohms to 4/8/16 Ohms?

[sluckey]

Let's get some more info about what you have. A stock 5F6A has four 8Ω speakers wired in parallel for a total impedance of 2Ω. So you NEED a 2Ω OT. But sounds like you are using an 8Ω OT? What is your speaker configuration? Let's see some pics. Also show us some pics that clearly show how you connected your new OT to the speaker jacks.

Connecting speaker jacks should be a simple straightforward task. But if you don't understand it's also easy to get it wrong. Good pics will probably help us sort it out.

[Oddvar]

Hi Sluckey, again.

I had a Weber 8ohms Outputtransformer in the amp uptil now.  The amp was built after the Weber 5f6a layout.  I had a tech finish the final hoopups, with two jack outputs in 8 ohm each.  Suddenly the Weber OT stopped working and I have now bought a OT from Classic Tone, Amppartsdirect.  I want to have the possibility to use different ohming to go with different speakers.  Question is, since I was told this new OT could be used with the Weber 5f6a layout, I thought it was ok.  But I am a bit confused on how to connect the OT to the outputjacks, or what I need to connect it right.

[Oddvar]

 

[sluckey]

I don't think the speaker jacks are wired correctly, but your pic is not clear enough to be sure. Post another pic that is zoomed in on just the 3 jacks. I need to be able lo clearly see the lugs on the jacks. Need sharp focus, high rez , big pic.

[Oddvar]

I must admit to be in a bit of dark here...

[sluckey]

320x281 ain't hi rez. Give me something big enough to see! Something like 2000x1200.

[sluckey]

You have a brown jumper between two jacks. Cut that out. Got sound now?

[Oddvar]

It's not possible to upload hi res here...

But how would one connect 4 / 8 / 16 ohm to outpujacks without a switch?

[Oddvar]

The brown lead is ground?

[sluckey]

It's not possible to upload hi res here...

Sure it is! Just keep the file size under 800KB.

The jack that has the orange wire connected does not appear to be a Switchcraft jack. Is that correct?

[Oddvar]

The orange to the left is a tip-ground-switch jack.

[Oddvar]

The lead coming from the board is going to the tip on the jack right.  The middle and right jack is grounded together, The top brown lead is going from ground rigt to the left jack ground.  The 4 ohm lead goes to the tip right jack, 8 ohm in the tip middle and the orange is going to the tip jack left.  The yellow lead is coming from the board, I am uncertain on where to put that?

[Oddvar]

 

[pompeiisneaks]

If I'm seeing that right, you've got the common/ground wired to the tip and all the tips wired to that same connection which means all output goes to ground, so no, you'll not get any output that way.  The black wire 'should' be common/ground and connect to the ground of the jack (not tip). then you need to know which tap is which ohms and hook one of each up to a separate jack's tip connection.  (the long one with the curved part).  I believe you'll definitely want grounded switched jacks to remove noise as well because they ground out when not in use.  I think those looked like grounded ones. 

Sluckey can confirm for sure though.

~Phil

[sluckey]

Much better. The yellow wire from the board will connect to the 4Ω jack. The jack on the left is not a Switchcraft and I can't identify the terminals without an ohm meter. For now, temporarily disconnect the brown and orange wire from the left jack. Do you get sound from the other two jacks now?

Rather than trying to figure out that oddball jack, I'm just gonna post a pic showing how you would wire the three jacks if they were all Switchcraft 12A jacks.

[pompeiisneaks]

Here's a great picture of a switchraft 12A showing it in a way that should make sense by color coding it:

http://gaussmarkov.net/images/plugs3.bmp

Basically red is tip, green is ground and the silver one is the 'switch' that you can ground if you need to (Which it should for multiple outputs or for input jacks, otherwise single outputs are Switchcraft 11 types)

And what Sluckey said ;)

~Phil

[Oddvar]

Hi Sluckey, did what you suggested, no sound still-

[Oddvar]

Funny thing is the only place that has a response is the presenceknob, it makes sound as I turn it?

[Oddvar]

This is the board in a bigger view...

[pompeiisneaks]

Sluckey mentioned that you should remove the leftmost jack as it doesn't look standard and it may be part of the problem, in that picture, its still connected.  The other two look like standard switchcraft 12A type,  You may even want to try just one jack at a time, and then make sure that works, then add a second jack to see if that does a well, etc.  reduce variables, know what works and doesn't.

~Phil

[sluckey]

I see that you have moved the brown and orange wires around on that oddball jack. Why? I want you to take the orange wire off that jack, tape it up, and don't reconnect it to anything until you have sound from the other jacks.

It's possible that you have other problems with the amp. Why do you suspect the original OT is bad? It's about time to post voltages for ALL tube pins. Also post the voltages on each of your filter caps.

[Oddvar]

Hi Sluckey, I think you might be right, but the old OT made cracklingnoises when I touched the leads, and the sound came in and out.  I'll be checking on the voltage.

[Oddvar]

Voltage:

V1 and 2: pin 1 and 6: 0.986 mv

V3: 295 v pin 1 and 6

V4 and V5: (6L6GC) pin 3 and 4: 475 v. pin 5: -5 an 51.9.

I'll do the rest also.

[sluckey]

V1 and 2: pin 1 and 6: 0.986 mv

That will certainly make an amp have no sound.

pin 5: -5

That's not good either.

[labb]

Pin 1 and 6 on V1 (if that is your first pre amp tube) should be about 150 VDC
Pin 1 and 6 on V2 (if that is your second pre amp tube) should be about 180 VDC
Pin 5 on the 6L6's should be about -48 VDC.

[Oddvar]

So what could the reason for lack of voltage be?

[Oddvar]

 

Hi guys, thanks to you I found the problem, one of the leads underneath the board from the volt drop resistor to the 10k B+4 was loos, now it all sounds great...

Thanks.

[pompeiisneaks]

Good to hear, you may want to look it over with a fine toothed comb to look for any other solder issues etc

Phil