Hiwatt DR-201 KT88 bass amp finished

[doctord02]

Thanks to both Mark Huss and Skyboltone for their advice during the planning and construction on this guy - as a result other than some buzz/noise reduction tweaking, this baby is finished!

[img:720:480]http://d.nix.home.comcast.net/~d.nix/my_watt_face.jpg[/img]

I've already rerouted some wires since this pic was taken, but it gives a basic idea of the clutter under the hood...

[img:720:480]http://d.nix.home.comcast.net/~d.nix/my_watt_guts.jpg[/img]

This used an Antek toroid power transformer, a NOS Fender PS-160 output transformer, a Hammond choke and a Weber chassis and custom faceplate. Essentially, it's a 4 KT-88 DR-201 that only has the normal channel. And it's loud and clean. *VERY* loud and clean. I haven't been able to turn it up past 3 with the 4x10 and 1x18 cabs connected and my P-J style bass plugged in, for fear of damaging structural stuff on the house. This one is a gift, but I'm already planning a second build that I'll keep since this turned out so well. I did hook it up to a 4x12 and it is unmistakably a Hiwatt. It makes any Twin Reverb I've ever played sound puny by comparison... It just will not distort until the preamp is up around 7 or so (I dialed the master *way* back), and even then it never got dirty, just kinda 'barked' like only a loud Hiwatt can do.

I'm pretty tickled.

[Bob-I]

Damn, that's a monster.

I remember the first time I heard HiWatt for bass. I saw Jethro Tull in 1970 while in college. I think it was Jeff Hammond on bass, but he had 2 HiWatt half stacks, Martin Barre had one. That BARK was just amazing.

Cool build.

[Colossal]

Wow, nicely done! Bet it sounds great.

[mhuss]

Nice! A lot of work there.

--mark

[gldtp99]

Very interesting build !!!!! I love to see DIY Hiwatts..............gldtp99

[Andy Le Blanc]

Nice....... "very" loud and clean is a understatement, bet your pant legs flap
in the breeze. Whats the transformer compliment?, and what plate dissipation
have you set the KT88 to operate at?

[doctord02]

Two more pix:

[img:780:520]http://d.nix.home.comcast.net/~d.nix/my ... f-doom.jpg[/img]

[img:720:480]http://d.nix.home.comcast.net/~d.nix/my ... eadcab.jpg[/img]

Andy, I just eyeballed the bias voltages based on a chart I had for KT88 plate voltages. Bias is apx -38 v, plate is apx 650, screen is 325.

PT is an Antek with two 230v windings stacked, OT is a Fender PS-160 new old stock I bought from Bob Rizzi (Risson Amps).

[jaxx]

fantastic job man!!!

i was searching the preamp scheme for the dr201 bass head,
wich preamp did you take for your?

thanx



Eddie

[KellyBass]

Wow!!!! You've GOT to post some clips of this thing!

There's just something about hiwatt for bass. bax tone stack, maybe?

I've built myself a 2 12ax7 preamp based around the hiwatt tone stack, and it's almost finished. it'll be interesting comparing clips of the two...

Well done build!!

[selloutrr]

awesome amp! Chris from Nirvana played a mod'd Hiwatt 201 on tour. full out through something crazy like 16 4x12 cabs daisy chained to match the impedance. 4 wide 4 tall during the last tour.

[Bear]

I'm assuming that the 201 pre is a DR-type? Does anyone have experience of the relative merits of this "AP" (All-Purpose) variety pre to the CP-103/"The Who" preamp for bass? I'm wanting some Hiwatt back in my life . . .

[Gaz]

Looks cool - the venting in the front reminds me of Sunn Model T. Where'd ya get the perforated sheet metal?

[Structo]

What a beast!
I'll bet it really thumps.

Good job on the construction and execution.