300B
"Scotty, we need more power!"
Stage 1
K.I.S.S. Principle
I've looked over the Web and it seems the three most popular 300B schematics are Herb Reichert's Flesh And Blood, J.C. Morrison's Fi Primer 300B, and Joseph Esmilla's JE Labs 300B. Although all three are much talked about, I just found more DIY sites with details about building the JE Labs 300B. I first saw the schematic at Angela Instrument's "How To..." Web pages and soon followed links to Joseph Esmilla's own site, which I can't recommend enough for newbies. Please visit his site as soon as you can as it is filled with tube projects galore.
Here is the schematic. I like the fact that all parts are labeled with values. No more guessing at wattage and voltage. Maybe that's why I decided to follow through with this project. At the moment I only have a partial parts list as I am not able to fund the complete pair of mono blocks. Total cost will be around $1,200 (US) with Hammond 1627SE output transformers (OPTs) and Chinese 300B tubes. More expensive iron can be had for $500 and up, but I want my 300B now! If the sound is not good enough, I can always upgrade to Electraprint or Magnequest OPTs next year or so when I have more funding. The Hammond iron costs only $160 (US) a pair. Magnequest FS030 trannies go for about $700 a pair. You go figure that out. By lowering the high-cost items as much as possible, I can put the money into the parts I don't want to unsolder in the future, such as resistors and capacitors.
If you look at all three of the designs, you'll notice they are quite simple to follow. Simplicity leads to sonic purity. That's my motto. And by making monoblocks, layout and parts changes are much easier to handle in the future, such as changing output iron. The old OPTs can then be used in another project, maybe a 2A3 amp? Hmmm... I had better stop my thoughts there as my preamp still needs to be completed....
Preliminary Parts List
**** Resistors ****
PARTS CONNEXION
8 pieces - 47K 1w - Riken Ohm 1 Watt 1% Carbon Film Resistors EACH $2.70 x8 = $21.60
2 pieces - 470 1w - Riken Ohm 1 Watt 1% Carbon Film Resistors EACH $2.70 x2 = $5.40
4 pieces - 1K 1w - Riken Ohm 1 Watt 1% Carbon Film Resistors EACH $2.70 x4 = $10.80
4 pieces - 100K 1w - Riken Ohm 1 Watt 1% Carbon Film Resistors EACH $2.70 x4 = $10.80
4 pieces - 220k 1w - Riken Ohm 1 Watt 1% Carbon Film Resistors EACH $2.70 X4 = $10.80
Mouser
2 pieces - 3.3K, 5w - Vishay Wirewound - $1.68
8 pieces - 3.5K 5w - Vishay Wirewound - 4 resistors in parallel = 880 ohm 20w - $6.72
2 pieces - 50K 25w - Vishay Aluminum - $6.12
Angela Instruments
2 pieces - 100K pot - 3. Alps Blue mono 100K volume control pot. EACH $19 x2 = $38
2 pieces - 50 pot 2w - 2. Allen-Bradley 50 ohm 2W carbon pots with long shaft... non-locking .625" long slotted screwdriver adjust solid shaft...Only ten to sell. EACH $10 x2 = $20
**** Caps ****
2 pieces - 630V Angela Copper Foil Paper In Oil Signal Capacitors - .22/630VDC, 35 x 25mm. SUMMER SALE PRICE! $20 x2 = $40
2 pieces - Premium VK Black Gate Capacitors - Radial Leads. 47uF/160 VDC, VK, 12.5mm x 25mm. SUMMER SALE PRICE! EACH $13 x2 = $26
2 pieces - Standard Type Black Gate Capacitors - No. 17. - 100uF/100VDC, radial leads...popular bias cap...16mm x 25mm. SUMMER SALE PRICE! EACH $6.50 x2 = $13
2 pieces - 1. Angela/ASC Oil Capacitor, 15uF/600VDC, 1.75" diameter, 3.75" tall. SUMMER SALE PRICE EACH $9 x2 = $18
2 pieces - 3. Angela/ASC Oil Capacitor, 30uF/515VDC, 1.75" diameter, 4.625" tall. SUMMER SALE PRICE EACH $12 x2 = $24
2 pieces - 5. Angela/ASC Oil Capacitor, 50uF/515VDC, 2.50" diameter, 4.625" tall. SALE EACH $17 x2 = $34
**** Transformers ****
2 pieces - Angela Universal Power Transformer 380-0-380, 5v 3a, 6.3v, 5v - Two for $200
2 pieces - Hammond Choke 7-10 mH @125 mA - 193J 10H, 200ma, 82 ohms, 800VDC. SUMMER SALE PRICE! EACH $42 x2 = $84
2 pieces - Hammond Output Transformers - 1627SE 25W, 2K5, 160ma, 4/8/16 ohm - SUMMER SALE PRICE! TWO FOR $160
6SN7 / GZ37 tube socket (octal)
4 pieces - 2. Octal ceramic/gold, 1.125" etc. same as above, SUMMER SALE PRICE! EACH $6.50 x4 = $26
300B tube socket (4-pin)
2 pieces - 16. UX4 ceramic/gold, 1.1875". SUMMER SALE PRICE! EACH $8.50 x2 = $17
2 pieces - 1. 6SN7WGTA JAN Philips/Sylvania '80s NEW OLD STOCK - EACH $49 x2 = $98
2 pieces - 1. GZ37/CV378 MULLARD UK RECTIFIER TUBES1. GZ37/CV378 MULLARD UK RECTIFIER TUBES. Each $55 x2 = $110
Hammond Chassis
2 - pieces - Model 1444-30, 17"X10"X2". SUMMER SALE PRICE! $25 x2 = $50
2 knobs - stock from parts box
2 RCA jacks - Mouser
TCSS - 10 feet?
Speaker Binding Posts - 2 pairs
IEC jack - Mouser
Fuse holder - Radio Shack
2 pieces - 300B
Page under construction....
