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Today's Featured Head-Fi Blog: A Japanese headfier's monologue (Sasaki)
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@ Amb
Did you use glass or plexi-glass as a cover for the amp?
@ Ferrari
I very much like your sollution for the 'recessed' volume knob on the thick front panel. Could you give us some details? Also, where did you find that amazingly large knob?
.: ZMN :., Just as the enclosure, the knop is from ATI. The knop diameter is 44mm and the cut on the 6mm thick faceplate is 47mm diameter. The blue Alp RK27 is mounted on the sub-front pannel behind the 6mm faceplate (as visible on the pic below). The volume knop is therefore mounted about 4mm recessed. The drilling for the LED is 3mm from the front and 5mm from the back of the knop. The power wires for the LED used behind the knop have flexible silicon sheath to avoid that they will becoming tangled up as the volume knob is turned.
Gee that's flattering. Ferrari's and Amb's amps look absolutely professional, these guys are true pros in electronics and DIY. I do enjoy DIY, but honestly I am just an amateur, not in their league. Thanks!
I've been building a pair of Aleph-X's class A monoblock amplifiers, runs nearly 50W into 8ohm and peaks at about 60W into 6ohm, 4A of bias and 16V rails dumping 130W of heat constantly
I designed and etched the PCB myself, double sided pcb's are a pain in the arse to line up though
Straight DC coupled input and momentary power on switch called for a separate circuit to provide DC offset protection in the form of a relay on the speaker terminals that cuts out if the relative DC offset is too high, the amp is balanced out by design and the absolute DC offset from +out and -out swing quite wildly by a volt or 2 between ground when fully warmed up, so differential input on the offset protection circuit was needed. As a bonus, adding in a delay in switching the speaker relay on after power on is easily achived, I've dialed it in for a 3 second delay which seems to work just perfectly. When switched off, a transistor shorts the capacitor feeding the relay driver, turning the speaker relay off instantly once powered down eliminating any strange hiss/hum/thump as the big capacitors drain
A solidstate relay switches power feeding the main power transformer, inrush limiting is supplied with zero crossing built into the ss relay so the relay wont turn on until the mains voltage is at the 0V part of its sinewave cycle and the transformer and capacitors charge up at the same rate that the mains sinewave does, eliminating sharp turn on transients
Built as a complimentary pair, the chassis's are a mirror image of each other
One is fully finished and working just great with the only thing missing is a top and bottom to the chassis, for which I have to source some nice perforated metal of some kind. the second amplifier is mostly done
Not exactly headphone related but audio all the same
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Audio electronics- Where we strive for inefficiency
Not exactly headphone related but audio all the same
Nice amps! Incidentally I just PM'ed Kevin Gilmore asking whether he finally designed a circuit for some 400w and 800w amps he had a couple of years ago among his future creations. A speaker amp is my next DIY project.
Great! Thanks for sharing the tricks as well as the pics.
@rsaavedra
Er, not professional? I bet that seeing all these creative designs, especially the ones build completely from scratch, will inspire many others to start sketching their own enclosure. It's threads like this (and posts like yours) that take away hesitations and motivate to be creative.
USAFA: Audigy 4 (roommate's computer) ---> DIY GB-150D-based integrated amp (stereo configuration, remote-controlled, power-on delay for output, and heavily class-A biased (3.9mA/channel) LM4562NAs used in preamp section) ---> Yamaha NS-527 (modified with Vifa 6 1/2" woofers, Panasonic film caps in crossover, and heftier internal wiring)
Ghey-C'97 (my piece-o-crap issued laptop) ---> PPAv2 (class-A biased AD8620 (2.5mA/channel), 8600uF pre-regulator, LM338 high-current regulator, 40mA/channel output bias) ---> Grado SR-225 (yes, I bring my headphones home from the Academy during leave)
Where did you find/order that case? I'm interested in building a speaker amplifier myself.
I built it myself
1 of these, cut off the holes on the ends and then cut the panels in 1/2 and you got your front and back, then carefully drill holes to bolt to the heatsinks that then become your side walls
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Audio electronics- Where we strive for inefficiency
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