During the site sluggishness and waiting for its migration, I took to finally machining a Hammond chassis for another solid state integrated amp project.
Cut, drilled and ready for the 7 individually designed boards/modules, transformers and controls/lights and stuff.
Cut, drilled and ready for the 7 individually designed boards/modules, transformers and controls/lights and stuff.
No Faraday cage except the chassis it sits in. The Micro-Audio PSU’s have been found to be very quiet in the human audible range - I’m sure there is noise at the switching frequency (there has to be some) but if one looks at the measured noise floor of the SMPS used in the Warp-1 Class D amp with inputs shorted, it’s essentially noise free where it matters - below 20kHz:
On the bench at the factory for speaker building is the prototype of the bookshelf TL speaker. It’s coming along very nicely - the exterior cabinet has been oriented and ready for satin finish black paint. Drivers have been test fitted to the removable bamboo baffle and crossover board and speaker binding plate installed. Waiting for some nice premium copper Viborg binding posts.
There is some family resemblance to the Vanguard, naturally. But the woofer and crossover are different.
There is some family resemblance to the Vanguard, naturally. But the woofer and crossover are different.
Do that sweep to 1MHz... It still matters IMHO. Either you can feel it, you find a harmonic, or it can just waste output power 🙂
The problem is that audio interfaces such as a Focusrite Solo, 2i2, 2i4 etc. (what we use for the FFT) have hard cutoffs a little above 20kHz.
On my bench tonight was a dual mono TPA3255 build, using JLesterP's latest D400 mono boards, Connex Electronic SMPS600Rs PSUs, xrk971's BTSB. I already moved it to my living room after it passed some initial tests. The sound is fantastic, a lot of bass authority, crisp and clear highs, it's only been running for about 30 minutes so I can't say too much more. For anyone with sharp eyes and zooming in, I did adjust the gain on the BTSB to +12dB from the +6dB in the picture. To pair with this build I will be doing a 3 board TPA3255 build in a separate chassis, a D400 board for center channel, and 2x D200 MKII boards to handle surround and back channels. For that I plan to pick up a handful of modushop risers, and run the amp boards on their side, BTSB's will be stacked, potentially on their side as well, not sure yet as I haven't ordered the chassis. I'll be doing black faceplate again with the same power switch to keep things consistent.
Very nice work! I see you are using one of those COTS SSR’s for the main on/off. I should get the SFP Plus (SFPP) released one day - it has built in external triggered SSR for power on off.
Thanks X! I will certainly be buying a few SFPP's when they release. The built in temp sensor shutoff is something I really like for transistor amps. The Crydom in there is rated for 25A, I have it stuck to a 40x40x20mm heatsink with some thermal paste, and bolts to hold it down, I think at most this build would peak at 10-12A, the heatsink is probably overkill. With a fully vented cover everything stays nice and cool.
On the bench tonight is the Bob Carver RAM285 amp prototype unit undergoing final assembly. That’s a nixe looking rear panel. Those Viborg binding posts look great.
Hmm, Viborg 5 way posts?
Mouser doesn't carry them.
And from what I've read, they're made of "pure copper", and pricy.
Well, copper is a soft metal, easy to bend, nick, just as wire is.
I'd doubt their hardy enough to stand up to long use.
Mouser doesn't carry them.
And from what I've read, they're made of "pure copper", and pricy.
Well, copper is a soft metal, easy to bend, nick, just as wire is.
I'd doubt their hardy enough to stand up to long use.
Viborg posts come in many grades and finishes. Pure copper is one and it’s quite durable as a binding post. I have that as standard on my Warp-1 amp. There is also copper plated brass and gold plated copper finish. I source them direct from the manufacturer. These are chrome plated brass conductors and POM insulator and black chrome plated brass knobs.
Super job, Mikebarney! Wonderful write up too.
https://sites.google.com/site/mpbarney/xrk-tpa3255-amplifier
Note that the SMPS 630SO has an on-board remote on-off connector (“STDBY”). You could use an external 12v to trigger a relay to close that contact versus using the remote to activate a HV mains relay. The PSU would be in standby mode until activated.
https://sites.google.com/site/mpbarney/xrk-tpa3255-amplifier
Note that the SMPS 630SO has an on-board remote on-off connector (“STDBY”). You could use an external 12v to trigger a relay to close that contact versus using the remote to activate a HV mains relay. The PSU would be in standby mode until activated.
On the virtual bench is the companion preamp from Vera-Fi Audio to go with the A40 amp. SE Class A (PCA circuit) for analog H2 signal processor with SS bypass option. Balanced and SE input and output, MM/MC phono stage, selectable gains, remote control motorized volume and mute, 2W into 32ohm headphone amp. Custom CNC aluminum chassis. Output drivers are high power LME49724. Ultra low noise custom power supplies.
This is going to be one cool preamp. Mechanically same width as A40 power amp.
Thank you to JPS64 and Darko M for helping me to design this.
Gains will be updated to: 0/6/9/14dB.
This is going to be one cool preamp. Mechanically same width as A40 power amp.
Thank you to JPS64 and Darko M for helping me to design this.
Gains will be updated to: 0/6/9/14dB.
Wiseoldtech won't see this but he should just buy a shaper if he wants "tone controls"...
Bass and Treble controls are good for low budget garbage by Lloyd's, or if you're trying to make 5 inch speakers make 30Hz, but I have only listened to my system flat for years - a good room and good speakers are much better than an eq-based kludge IMHO.
Bass and Treble controls are good for low budget garbage by Lloyd's, or if you're trying to make 5 inch speakers make 30Hz, but I have only listened to my system flat for years - a good room and good speakers are much better than an eq-based kludge IMHO.
On the bench last night was the Aksa Deltic amplifier. A wonderful design by Hugh Dean that I built 5 years ago. A nice little 75W class AB with BJT output stage and a unique singleton input stage for a harmonic profile that resembles a SE Class A amp. Unfortunately, I built the amp using cheap no name (well “ChongX” brand) rail caps and they have all bulged or started oozing and leaking. So I had to pull all 16 off and ordering some quality name brand replacements. Some Rubycon 4700uF 50v 18mm x 7.5mm pitch caps this time from Mouser.
Here’s one of the better looking ones. The bad ones have liquid coming out or completely split. They are rated 50v and the rails are only 45v.
Here is the measured FFT of the Deltic when it was working before the caps blew up:
Square wave test:
I’m going to do a proper job of tidying up the internal trafo wiring this time and add a speaker protect SSR too. Here was the rat’s nest of the earlier “lazy man’s” build:
It is a dual mono design so the soundstage and imaging are superb. Like all Hugh Dean amps, smooth and superb “foot-tapping good” dynamics with no hint of harshness.
I want to fix it because I would like have a good Class AB in the bedroom to go with my Vanguards.
Here’s one of the better looking ones. The bad ones have liquid coming out or completely split. They are rated 50v and the rails are only 45v.
Here is the measured FFT of the Deltic when it was working before the caps blew up:
Square wave test:
I’m going to do a proper job of tidying up the internal trafo wiring this time and add a speaker protect SSR too. Here was the rat’s nest of the earlier “lazy man’s” build:
It is a dual mono design so the soundstage and imaging are superb. Like all Hugh Dean amps, smooth and superb “foot-tapping good” dynamics with no hint of harshness.
I want to fix it because I would like have a good Class AB in the bedroom to go with my Vanguards.