Tube Amp Archive

I know the Dr Z Prescription is not made anymore (replaced by the Prescription ES), but I was just wondering is that amp the same as a Trainweck Liverpool?

Thanks drz400 for the suggestion of the cap at the input jack. That fixed my problem.

I have a Ceriatone/Toneslut kit that is picking up a local FM radio station. I have the input shielded and also shielded the run from the volume pot wiper to V1 pin 2. I also added resistors at the grids of these two stages. These things helped, but still not fixed completely. The pickup area seems ...

Sounds like a good plan. I can only get -38V with my circuit.

The reason I brought this up is because I am using the same circuit that is posted on the Express schematics. So I assume others would run into this problem also.

Kent

Andy, thanks for the reply. I will change the 220K resistor to give me lower current (a greater negative bias voltage).

When biasing the EL34s the bias pot is in the middle of the range so I believe everthing is working right. It looks like the bias circuit was designed to bias EL34s.

Kent

Hey Paul, I agree, I want to lower the current to the 21-23mA range, but I have no more bias pot adjustment. I can change a resistor (lower the 220K) in the bias circuit to give me lower current. I guess my question is, is no one else having this problem or does everyone just bias the 6V6 extremely ...

I just finished an Express clone with Ceriatone chassis/board and Moose transformers. Using EL34s I can bias the amp fine. I use 70% of max power dissipation method for the tube by measuring current at the cathode. But, using a 6V6 I can only set the minimum power dissipation to 12W, which I think i...

Allynmey,

Well, that leads to a couple questions. What is the impedance of the output transformer? What is the output voltage on the power transformer?

Thanks for any information.

Ampmodster

Allynmey,

Whose transformers/choke are you using. I am following your build very closely. I hope it sounds as good as it looks!

Allynmey

Wow! looks fantastic. That is a "Brand" I am looking to build. Where did you get the chassis?

Kent

Does anyone know what the tone stack pot taper is on the Komet 60? It has a 250K Bass and Treble pot and a 25K Middle pot, but I was wondering if the taper is audio or linear on those.