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About the Amp

About 5 years ago I read on the internet about the Epiphone Valve Junior amp and all of the mods done to them.  The goto place for information was www.sewatt.com, a forum site especially for SE (single ended) amps … I dove in head first. Then later on I started hanging out at the other http://www.wattkins.com family sites, www.ppwatt.com for PP (push-pull) amps and then later on to the “Community Center” www.wattkins.com.

One of the things that materialized from wattkins.com was the development of a SE amp using a 6U8A and 6AQ5 named the Savage Croaker — the Savage part was due to a misreading of a forum member’s name and the Croaker part is a regional term for a $100 bill.  That lead to a ‘branch’ referred to the “Tone Per Buck Club” which spawned  two SE “Croaker” amps one with the triode/pentode 6U8A and a second with a 12AX7 dual triode in the preamp.  Following close behind was the push-pull “Pushy Croaker”.  Some people at this time had experimented with Russian surplus tubes; the 6N2P preamp tubes, a 12AX7 like tube with different heater wiring, and the 6P1P a 9-pin equivalent to the 6AQ5.  The amp uses three 6N2P and two 6P1P tubes, available for about $2 each … I just priced six – 6N2P and four – 6P1P with shipping the total was $28.

One of the latest circuits discussed was taking the well known and well respected preamp design  from Ken Fischer’s Trainwreck Express and ‘gluing’ that to the “Pushy Croaker” output section to make a 10 watt push pull “Thrifty Wreck”.  An Australian member with the handle katopan did the development of the Thrifty Wreck circuit especially the necessary tuning of the PI (phase inverter) and output section to deal with the voltages and operational characteristics of the 6P1P tube. Here are the links to katopan’s Chosen Audio Thrifty Wreck page  and his Trainwreck Testing page

At this time I know of four Thrifty Wreck (TW) amps that have been built.  Katopan built the development version in a test chassis using a point-to-point (ptp) layout using a style like the Gothik Ring concept, another forum member, Dust Puppy drew up an eyelet/turret board layout and built TW #2 using his layout.  My friend JazzBox built TW #3 using katopan’s ptp layout, and finally within the last couple of weeks I’ve finished my eyelet board build based on Dust Puppy’s layout.

One of the interesting things is the ThriftyWreck amp is easy to build and does not seem to be as tricky to build as is reported in the similar circuit higher wattage amps.

I’ll include links to the schematic and layouts hosted on another site, but if you are interested in building or discussion the amp you should become a member at wattkins.com

schematic: Thrifty_Wreck_Schem.pdf

ptp layout: ThriftyWreck_PTP_Layout.pdf

eyelet/turret board layout: ThriftyWreck_Layout_rev2.jpg

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1 Comment (+add yours?)

  1. rockmumbles
    Nov 28, 2012 @ 15:18:05

    Here’s a post from my friend Dave in the UK, he has built a Thrifty Wreck amp, his runs at lower voltages but seems to work much the same …

    Ok guys. Great day in the studio. I used the 22uf bypass cap for single coil lead parts and 2.2uf for humbuckers. On a switch for now.
    In a blind test against a peavey 5150, a Mesa boogie Roadster and a JCM 800 2021 from 1983, the TW won on every track. The producer was blown away. He commented that the TW had loads of gain but retained the note definition and didn’t sound overcompressed almost like it was clean and distorted at the same time. So basically the clarity and articulation of the amp made it stand out from have other amps by a mile.
    This is a massive compliment cos this guy earns a living from producing hard rock bands in the UK and has toured with Megadeth, and other well known metal bands…
    I’m over the moon!!!
    … just for the record this was for lead tones only, not tried a comparison for rhythm tones yet.

    Here’s a video of Dave with his Thrifty Wreck recorded at the end of October …

    Reply

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