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Thread: Ceriatone Dizzy 30 - Matchless DC30 Clone

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    Ceriatone Dizzy 30 - Matchless DC30 Clone

    I just finished up this kit with a few modifications:

    Changed cathode bias resistors to 75 ohm - 10 watt. The EL84s were drawing too much current with the standard 62 and 68 ohm bias resistors. The EL84s are good old stock used tubes.

    Transformers built by Bob Wood - Transformer Design and Supply

    Rectifier - Weber Copper Cap WGZ34

    Changed master volume to the Larmar type. This was a great improvement in tone over the standard crossline master volume. Used a dual ganged 250K pot and bridged the wipers to ground with two 2.2M resistors. I removed the two 220K grid leak resistors.

    Changed the channel 2 volume pot to a pot with a push pull spst switch so I could switch the 180 pF bright cap in or out. A 5M resistor is in parallel with the cap to keep it from popping when switched.

    Installed a Vari-watt from Skipz circuits. I tried it with the whole amp scaled and also with just the power amp scaled. The unit worked OK with the whole amp scaled, but I had an annoying hum with just the power amp scaled. With the power amp scaled, the preamp power supply is not filtered by the choke. My guess is that the preamp needs to be better filtered. So I rewired it with the whole amp scaled and the hum vanished. On this amp, with all the preamp gain available, the Larmar MV seems to be much more useful than the Vari-watt. Tone-wise, the MV also sounds a lot better.

    I was shocked how loud this 30 watt amp can be when cranked up. Fortunately the MV tames it perfectly when needed.







    Ceriatone Dizzy 30 - Album - TinyPic - Free Image Hosting, Photo Sharing & Video Hosting

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    Senior Member trevorus's Avatar
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    Love the looks of it. I need to try one of Ceriatone's kits. Just need to find the cash to do it!

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    The shipping cost can add up because of Ceriatone's location (far East). It was $400 total for the chassis, front and backplate, loaded turret boards and parts including shipping. Transformers are extra. One of the reasons I bought the TDS transformers was because they are in the US, and the shipping cost is much lower. I'll likely buy a head cabinet from Gabkits, who are located close to me.

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    Had a friend build me a 3/4 inch baltic birch box-jointed cabinet and I covered it in tolex.




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    Man what a nice job you did congrats nice an clean

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    Just thought I'd post some info on rectifiers for the DC30:

    OK, here's the results:

    Rectifier-------------Amps (nominal)------------- Heater Voltage-----------------B+
    Weber WZ34----------0------------------------------5.20-----------------------------340
    Weber WU4GB--------0------------------------------5.20-----------------------------307
    GZ34-------------------2-------------------------------5.17-----------------------------350
    5R4---------------------2-------------------------------5.14-----------------------------298
    5AS4A------------------3-------------------------------5.14-----------------------------317
    5U4G Old ST----------3-------------------------------5.14-----------------------------299
    5U4GB-----------------3--------------------------------5.09-----------------------------320
    5V4 x 2----------------4--------------------------------5.06-----------------------------348

    So, the heater voltage regulation is 2.7% in the range of 0 to 4 amps.
    The PT remained very cool, and I couldn't feel any heat in the heater
    wires coming out of the transformer. Looks like the PT can safely supply
    4 amps to the rectifier. Interesting that the B+ is almost identical whether
    you use a single GZ34 or two 5V4. The Weber copper caps drop about 10V
    more than the vacuum tube equivalents.

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