New 50 Hiwatt build w/ Jimmy Page & Brilliant preamp

  • Thread starter Thread starter Travis
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Travis

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Hey fellas,
Longtime lurker, occasional poster, heavy duty assembler/solder sniffer/guitar tone lover with a new amp build. This is a 50 watt Hiwatt build in a 50 watt Plexi headshell/chassis. The power section, and EQ are the same as a DR504 but the main difference in this amp from a stock DR504 is one channel is the Jimmy Page/SAP preamp. It's a primitive "switching" circuit but it's highly effective and to me it's actually MORE musical than the super in depth two or three channel amps out there because the tonal changes aren't so drastic. It has a fatter version of the brilliant channel without the Jimmy Page/SAP switching for a slightly different tone on the other channel. Power transformer is a Heyboer Partridge clone, with the output being a Classic Tone 50 Watt Marshall OT; I might upgrade that to the Heyboer OT in the future but this amp sounds pretty great as is. I also added a switch that toggles a couple of cathode bypass caps on or off depending on which tone I'm going for; both were Hiwatt specs at one point or another. I'm amazed at how loud this amp is and how quiet the noise floor is.

Sound clips to come if I can figure out how to post them on here. I get the whole amp thing; the computer thing I struggle with sometimes.

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Enjoy!
 
Sweet build! It's a cool coincidence that I'm about to build a Marshall circuit (mini-Major) into a Hiwatt chassis.

Just curious but what makes you believe a Heyboer is an upgrade from the Classic tone? I've never used Classic Tone but have built several amps with Heyboers. No complaints on the Heyboers just curious. FWIW, Merren Audio makes a DR103 OT so maybe he could make a 50W version for you. He's making my mini-Major transformers.
 
IndyWS6":106nc2a1 said:
Looks cool :thumbsup:

Details?
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Thanks man!
I just spent a bunch of time refining this amp over the weekend. It's sounding particularly amazing now; just a fucking massive 50 watt. I had to do some moving around of a few components to get the circuit to be stable (it was oscillating when certain controls were zero'd), including moving the 22k series resistor out of the wiper of the EQ directly to the input gird of the of the first PI tube. That really stablized the amp. It was unstable because I changed the Jimmy Page/SAP to more of a JCM 800 preamp; the cathode follower isn that gainy and the extra gain made the amp unhappy. But I kept the footswitching arrangement of the SAP so you can still engage the cut on the gainier channel. Today, I have to balance the B+ for the first gain stage; they are little high so it's slightly stiff right now but for any kind of fast playing, that's perfect-its faster. I'll post some clips when I feel it's really happenin'. Maybe today?

SpiderWars":106nc2a1 said:
Sweet build! It's a cool coincidence that I'm about to build a Marshall circuit (mini-Major) into a Hiwatt chassis.

Just curious but what makes you believe a Heyboer is an upgrade from the Classic tone? I've never used Classic Tone but have built several amps with Heyboers. No complaints on the Heyboers just curious. FWIW, Merren Audio makes a DR103 OT so maybe he could make a 50W version for you. He's making my mini-Major transformers.
Click to expand...

I actually take that statement back about the Heyboer; I have three Classictone OT's. They are all superb and for the money it's close to impossible to match the quality. I only said that because it's not quite the same specs as the Partridge originally used in Hiwatts (the impedance ratios slightly different but garner pretty much the same sonic results). I ordered a Heyboer Hiwatt 50 watt clone from Mojo and it was a disaster. They made the bolts holding the bell-end on too long so you literally had to disassemble the transformer to mount it to anything and in the process I managed to destroy a $130 OT buy just removing two screws. That turned me off from Heyboers for life. It would cost half the price of the transformer to send it back. That loss hurt like Hell but I knew that the Classictone would be perfect, half the price of the Heyboer and I should have used them from the start. So goes life. Could be a nice doorstop.

Heyboer makes good stuff, but the price for what you get is just completely unwarranted unless its a custom piece and apparently even those aren't that surefire as stated in the example above. I have heard some pretty lame Heyboer OT's.

Merren makes great stuff! Thanks for the tip on that; that might be in the future! :thumbsup: It's really that the options are fairly limited for an exact Hiwatt spec OT and I ain't using no plastic bobbin Mercury Magnetics "sorry excuse for a transformer" in my amp. No sir. :rock:
 
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