So they sent me E88CCs ?

[gtrplayr1976]

Well. An issue that appeared overnight. I was going test the amp out. Plugged in a guitar, and when I hit the standby switch I got a motorboating sound. I tried every input ,and no input. So I started poking around ,and could find nothing obvious to me. I then started pulling tubes ,and this is what I noticed.

V1 = No change (left it in place)
V2 = Noise stopped
V3 = Noise stopped

I swapped tubes around ,but nothing changed. So, the noise stopped with either V2 ,or V3 out. I'm attaching a link to the sound. Maybe it will help.

18 watt Marshall clone motorboating - YouTube

[gtrplayr1976]

That's a good one Terry. Thanks

[big_teee]

Here's a TMB Layout at the Triode store.
I built my 2204 with there layout, haven't used the 18w, but it looks good.
http://site.triodestore.com/18WTMB.pdf
T

[gtrplayr1976]

Thanks mac.

[mac dillard]

Take a look at the schematics on this site.

18watt Schematics, etc.

The 18 watt Lite IIB is simple and pretty good. Also Z Phil's 18watt Superlite TMB. Not sure where to find the Superlite TMB schematic. It is a shame that the 18 watt forum site crashed and burned.

[gtrplayr1976]

New tubes on the way. No charge of course

[gtrplayr1976]

Thanks J M I sure hope it does. I should have changed the scheme to eliminate the tremolo ,and add TMB . I want to do that later. I never use tremolo. Maybe a master volume later. I'll just see how it sounds first.

[J M Fahey]

I *bet* it's a *killer* sound .
Congratulations

[gtrplayr1976]

Thank you. I will see if I can figure this out. By the way. I found some used 12AX7s ,and installed them last night. Amp fired up, seems to have a slight bit of hum with no input. I will be testing it tonight to see what it sounds like.

[J M Fahey]

I just wanted to see what it was running at.

As Enzo would say ... "Ohm's law *still* rules .... as well as all others"
To get tube (pair) current: measure voltage across cathode resistor (= to cathode to ground), divide by resistor value.
Then measure +B voltage, substract cathode voltage , and multiply by current you just found, will give dissipation for the tube pair in Watts.

Divide by 2, hoping both tubes are matched .

[gtrplayr1976]

Well, Mojotone is considered a "serious" company, but even themselves acknowledge in their assemby manual:

and this is clearly one of them.
If they bark at your "already having plugged the tube without asking" tell them you are no Tech, seeing "ECC something" made you think it was some 12AX7 equivalent and started asking in Forums "why doesn't my E88CC filament work" and that you expect them to send the proper tube, of course you will send the wrong tube back.















I think you will have no problem with it.

As of the Bias: congratulations, it's cathode/self biased so no adjustments

Oh don't worry I'll get it taken care of. I still have to send them pictures. I knew there was no adjustment for the bias. I just wanted to see what it was running at. ... Thanks for the help !

[J M Fahey]

Well, Mojotone is considered a "serious" company, but even themselves acknowledge in their assemby manual:

Packaging mistakes are rare for Mojo but
double check us before you start your build.

and this is clearly one of them.
If they bark at your "already having plugged the tube without asking" tell them you are no Tech, seeing "ECC something" made you think it was some 12AX7 equivalent and started asking in Forums "why doesn't my E88CC filament work" and that you expect them to send the proper tube, of course you will send the wrong tube back.

I think you will have no problem with it.

As of the Bias: congratulations, it's cathode/self biased so no adjustments

[gtrplayr1976]

Would there be somewhere on here that might tell me how to check the bias on this amp ?

[gtrplayr1976]

Can you link to the kit sellers site?

British 18 Watt Style Head Amplifier Kit

[J M Fahey]

I have contacted them. He tells me they don't even sell the E88CCs , So I have to send pictures of the boxes ,and tubes. Geez...

Can you link to the kit sellers site?