Fairfield County Signature (Two-Rock JM Sig) Build Thread

[rccolgan]

Sorry Ryan that sucks. It's funny, but not funny. A company based entirely on somebody else's ideas being offended at someone doing the same thing as them (and for a discontinued amp no less and at a scale that will not impact their bottom line).

I'm interested in the faceplate tutorial particularly for Taylor's ODS chassis.

Thanks!

-Dan

Thanks, man! Yeah it was a real bummer. Live and learn.

The software is pretty great. If you have a DXF or PDF of his chassis faceplates, it could easily be turned into a editable faceplate.

[jazzbass]

Hi,

Just now I read the news that H. Dumble left us.
He left us too young, he was one of the greatest innovators in the music industry.
R.I.P.

Franco

[jazzbass]

Hi Ryan,

I'm sorry you had to stop building the faceplates, to be honest they were too much the same as the originals.
For us building enthusiasts it is a pleasure to build these amplifiers, it is also honoring the ability of the companies that build them even if (the latter) are copies with some variation of projects of other H. Dumble projects. About which I read that he left us, probably yesterday and still at a young age.
R.I.P.

Franco

[rccolgan]

I believe the Ceriatone JM chassis layout is compete! I think I might prefer this better than the original. The extra features and shorter gain pot wires are nice

[jazzbass]

Hi Ryan,

for the first JM I built I used a chassis from Nik, a great builder and exquisite person. I built the others from blank chassis bought from TubeTown. In my opinion they have a somewhat thin aluminum frame for a 100 watt due to the weight of the transformers but they are fine for a 50 watt.
For the next JM under construction I bought your excellent boards and ordered the chassis from AN but I agree with you and, if I have the opportunity to build more, I will ask Nik for the chassis.

A hug
Franco

[rccolgan]

I think we can finally call the 120k on the Wonderland layout an error. Today I was poking around inside my Fairfield build and I measured the 220k and my meter displayed 122k! This leads me to suspect that the resistors were measured and this one was missed upon a visual color band inspection.

[Tweezy]

Just completed one of these, it sounds great! Wanted to share my measurements to gauge everyone's thoughts. Do you think the plate voltage is too high? Thanks!

Measurements.jpg

[rootz]

Not really. Is this for a 4x6V6 amp? Bias is really low for 6L6 (which would give higher than expected plate voltage), but pretty good for JJ 6V6's.

[Tweezy]

No, it is a 4x6L6. I'll adjust the bias to get it closer to 445v for V9-V6.

[erwin_ve]

Based on your plate voltage: your voltage across the 1R resistors should be approximately between 35mV and 46mV.(50%-70% of a 30w tube)

[Tweezy]

Thanks for the replies. I was incorrectly referencing bias calculations for 6V6

Down to 445V and biased at 45mV and 40.1mV

[rootz]

Haha, well you were half way there! And, does it sound better too?

[Tweezy]

Yes, totally - it was breaking up too early.

[jazzbass]

Hi Ryan,

I am finally completing the construction of the JM / Fairfield County Signature with the boards I bought from you and a chassis bought from Amplified Nation.

I would like to use a couple of transformers that I have at home, they were mounted on a Hiwatt 50Watt but the power transformer does not have the tap for the bias and I tried to exploit a branch of the transformer using a Hiwatt scheme but without result, the current of biass remains too high. A diagram by M.Hartman "SSS Power amp & Power Supply" gives a solution but I don't know if it is correct. Do you have any advice for me?

It is the fifth JM that I build but the first with your cards and I had some difficulties because (for obvious reasons) the layout I found is only the one suitable for the Ceriatone chassis but, apart from some headaches, i finished building if i solve the bias problem.

The next amplifier that catches my attention is the SSS # 004 but I want to build it in a standard 19 "chassis, I searched Ampgarage for a discussion about this build but I found nothing, maybe the topic is too old and the article was deleted Can you help me?

Thank you

Franco

[rccolgan]

Hey Franco! Glad to hear your feedback on the build! My boards are really close to Taylor's layout so I figured it would be easy to simply follow Taylor's diagram but maybe I need to make my own. This is good!

Adapting circuits for bias voltage is a little out of my expertise so maybe sometime can jump in and we both can learn from it.

Rafael built SSS #004 inside a 19" chassis and used the Ceriatone SSS layout for the circuit topology. I know the Ceriatone layout is on TAG somewhere here I can try to find when I'm in front of my computer if you don't find it first