As the Stones put it "Just may be the last time"

T-Rex

T-Rex

Well-Known Member
Country flag
Project #2 that is extremely dear to me. A new "lunch box amp" build dedicated to my furr baby that left us behind. When I traveled the guitar show circuit I was into building the 10watt 6AQ5 powered amps. I would tell people that they were like my dog, small but mighty. I named a couple after him, called them Baby Jakes.

I have dedicated myself to building one more amp that is a lunch box style. New Hammond black chassis and New black Hammond steel cage top. 10 watt 6AQ5 power tubed, with a Fender Tweed 5D3 Deluxe theme coupled to the 10 watt power section. This will take a while, but I do have the turretboard finished. Pics below




 
Holes are drilled and knocked out. I figure at least 180 holes drilled in steps from starting bits to unibits. Just to drill a 6/32" screw hole is 4 drill progressions as you cant hog the sheet metal chassis or the bits twist the metal when they bite. Think I have about 7.5 hours in the layout, cutting , drilling, cleaning the bench in between relocating the chassis so the drill shards dont scratch the finish. I have everything where it goes, bear in mind this chassis gets a cage top. The silver screws are where I need ground contact. Black oxide screws dont conduct continuity for poop, but they look bitchin. My furr budy Jake would have approved this fabrication so far. Pics below







 
Certainly. Since the preamp up to the power tubes was built as a Tweed 5D3 Deluxe, when that model of Deluxe came out in 1954, it had on the far right as you are looking at the amp face on, a Mic input with no grid stopper and two other Instrument jacks to the left of that Mic input jack. Both of those Instrument jacks had their own " 1 each 1 meg to ground resistor at the jack and each has their own 68K grid stopper".

The idea back then in 1954 was the ability to plug in two different guitars and a microphone to the amp. The Mic input had a separate Volume pot and the two other jacks are combined to a single Instrument Volume pot. Both Volume pots are tied into a Tone pot.

Since we have evolved from "knuckle dragging back in 1954" those input configurations were not of much service to me. I took the Mic input and pot and put a 47K grid stopper on it and left it as a "Normal Channel" (no 1meg to ground). The two other inputs became a Low and a High jack, each with the 68K grid stoppers as per 1954 spec with the High Jack also having the 1meg to ground at the input jack. I revoiced the "Bright channel" coupling cap to a .022uF from the stock .047uF cap. Bear in mind both triodes are shared bypass cathode as in a Marshall JTM45.

This allows me a nicer "Bright channel" with a Low/High option, and a good Fender "Normal channel". I can now even channel jump between the two jacks of the Normal and Bright low and blend the two channels together as on a Tweed Deluxe 5E3, only with a Brighter option on the second Volume pot.

One may ask why didn't I just build a 5E3 Tweed Deluxe preamp then instead. My reason is the 5D3 Deluxe and the 5D5 Pro were the only two amps that Fender built with the 12ax7 as a floating paraphase phase invertor. To invert the signal for the other power tube required a gain stage, but you can't have one inverted signal higher that the other going to the power tubes. If looking at a schematic at first glance it looks like a long tailed pair PI, but it is not. Thus the designed floating paraphase PI. I think the tone has a unique quality.

The Valve Wizard -Paraphase

www.valvewizard.co.uk
 
Last edited:
T-Rex said:
Certainly. Since the preamp up to the power tubes was built as a Tweed 5D3 Deluxe, when that model of Deluxe came out in 1954, it had on the far right as you are looking at the amp face on, a Mic input with no grid stopper and two other Instrument jacks to the left of that Mic input jack. Both of those Instrument jacks had their own " 1 each 1 meg to ground resistor at the jack and a their own each 68K grid stopper".

The idea back then in 1954 was the ability to plug in two different guitars and a microphone to the amp. The Mic input had a separate Volume pot and the two other jacks are combined to a single Instrument Volume pot. Both Volume pots are tied into a Tone pot.

Since we have evolved from "knuckle dragging back in 1954" those input configurations were not of much service to me. I took the Mic input and pot and put a 47K grid stopper on it and left it as a "Normal Channel" (no 1meg to ground). The two other inputs became a Low and a High jack, each with the 68K grid stoppers as per 1954 spec with the High Jack also having the 1meg to ground at the input jack. I revoiced the "Bright channel" coupling cap to a .022uF from the stock .047uF cap. Bear in mind both triodes are shared bypass cathode as in a Marshall JTM45.

This allows me a nicer "Bright channel" with a Low/High option, and a good Fender "Normal channel". I can now even channel jump between the two jacks of the Normal and Bright low and blend the two channels together as on a tweed Deluxe 5E3, only with a Brighter option on the second Volume pot.

One may ask why didn't I just build a 5E3 Tweed Deluxe preamp then instead. My reason is the 5D3 Deluxe and the 5D5 Pro were the only two amps that Fender built with the 12ax7 as a floating paraphase phase invertor. To invert the signal for the other power tube required a gain stage, but you can't have one inverted signal higher that the other going to the power tubes. If looking at a schematic at first glance it looks like a long tailed pair PI, but it is not. Thus the designed floating paraphase PI. I think the tone has a unique quality.

The Valve Wizard -Paraphase

www.valvewizard.co.uk
Click to expand...
Very cool, Terry! School is in session… :cheers:
 
T-Rex said:
Project #2 that is extremely dear to me. A new "lunch box amp" build dedicated to my furr baby that left us behind. When I traveled the guitar show circuit I was into building the 10watt 6AQ5 powered amps. I would tell people that they were like my dog, small but mighty. I named a couple after him, called them Baby Jakes.

I have dedicated myself to building one more amp that is a lunch box style. New Hammond black chassis and New black Hammond steel cage top. 10 watt 6AQ5 power tubed, with a Fender Tweed 5D3 Deluxe theme coupled to the 10 watt power section. This will take a while, but I do have the turretboard finished. Pics below




Click to expand...

As always, beautiful work Terry. Rest In Peace sweet little Jake. You are certainly missed.

David
 
You must log in or register to reply here.
Back
Top