DIY - RIAA phono kit, head amp, buffer, and power supply

neobop · « **on:** 8 Mar 2014, 04:27 pm »

Saw this recommended on another forum with a glowing endorsement. J FET kits are said to be easy if you can solder. Phono kit is $89. Power supply kit is $69 and is 18VDC.

I haven't heard these, just thought I'd pass it along:
http://boozhoundlabs.com/collections/kits/products/bhl-audio-jfet-phono-preamplifier-kit-2sk170-riaa

neo

Brad · « **Reply #1 on:** 8 Mar 2014, 05:13 pm »

I just built one of the phono stage kits, and I highly recommend it.
Very easy assembly.

He also has a new active crossover kit coming soon.

TomS · « **Reply #2 on:** 8 Mar 2014, 11:15 pm »

Mike Galusha has one with a battery supply and it sounded terrific at his place.

jtwrace · « **Reply #3 on:** 8 Mar 2014, 11:28 pm »

Quote from: TomS on 8 Mar 2014, 11:15 pm

Mike Galusha has one with a battery supply and it sounded terrific at his place.

Yep. No brainer IMO.

poseidonsvoice · « **Reply #4 on:** 9 Mar 2014, 12:13 am »

I've heard this one as well and thought it was excellent.

Best,
Anand.

neobop · « **Reply #5 on:** 9 Mar 2014, 12:55 am »

According to the guy who posted this, it's really easy to build. The board is marked like C-1 and R-1 and all you have to do is insert the corresponding capacitor or resistor. What you have to watch for is the orientation of capacitors. They have to face the right direction.

You could probably power one of these with a couple of rechargeable 9V batteries hooked up in series. I've also seen 6V lantern batteries, but I don't know if they're rechargeable. You could use 3 of them. The power supply kit is also inexpensive, so you have options. Looks like Boozhound labs is on their way to offering a complete stereo, minus speakers.
neo

pumpkinman · « **Reply #6 on:** 9 Mar 2014, 02:07 pm »

I've never built anything before (ClassD amp yes but no soldering was required)
So I'm game. I will have tech support from one of our members here so I'm not to
worried. He has a power supply that's already built and will donate to my project.

To build a case I'll need to go up the garage so that'll be awhile.
It's still much to

mgalusha · « **Reply #7 on:** 9 Mar 2014, 03:16 pm »

I use this with a 24V LiFePO4 battery. This is the quietest phono stage I've ever used and works well, at least with my SoundSmith "The Voice". It doesn't have a lot of gain, mine is about 39dB if I remember correctly.

I have tried it with an HP lab supply with good results and with a dedicated supply I built, the weed wacker battery wins easily.

Mike

neobop · « **Reply #8 on:** 9 Mar 2014, 03:53 pm »

40 dB of gain seems standard for MM input. I thought it said 43dB, not much to quibble about. The pre-preamp has 30dB, so there's plenty of gain for a LOMC. Of course that's another kit. I think the power supply can be between 12 and 24VDC. Usually, the higher the voltage, the more headroom. I wonder if anyone has tried different voltages with similar supplies. There might not be much difference between 18 and 24V.

The deleted post shows what can be done if you're seeking a thing of beauty. I would try it in a cigar box or plastic so it's unshielded. If you don't pick up RF it might sound better. That's been my experience with other phono stages. If it doesn't work out you could always put it in an aluminum box.
neo

mgalusha · « **Reply #9 on:** 10 Mar 2014, 02:10 am »

Quote from: neobop on 9 Mar 2014, 03:53 pm

I would try it in a cigar box or plastic so it's unshielded. If you don't pick up RF it might sound better. That's been my experience with other phono stages. If it doesn't work out you could always put it in an aluminum box.
neo

Agreed, especially if one adds another stage for more gain. I redid the grounding a couple of times to get the noise as low as possible and to try and prevent RF from entering the chassis. I used an AL Parmetal chassis. Not pretty but works well.

G Georgopoulos · « **Reply #10 on:** 10 Mar 2014, 03:44 am »

yeah more gain stages means more noise RF then there is ps noise...etc...

jtwrace · « **Reply #11 on:** 23 Mar 2014, 02:18 am »

I built the Boozhound PS today. I just need to finish the case and wire it all up.

*Scotty* · « **Reply #12 on:** 23 Mar 2014, 06:42 am »

Some simple changes as to how the kit is implemented might yield an audible improvement in the sound of the kit. Replace the 3amp Schottky diodes with 6 amp rated Schottky diodes. Mount the the circuit board on 1.5in tall standoffs in an enclosure that has at least a 3 inch high internal dimension.
Doubling the amperage rating on the diode bridge makes a valuable reduction in the power supply impedance. Increasing the space above and below the circuit board to 1.5 inches is virtually the same sonically as mounting the circuit board in a plastic chassis without the RF problems. You could also up the the transformer to a 150VA rating,once again to lower the power supply impedance. I use a 225VA rated transformer and a 15amp rated Schottky diode bridge.
One more worthwhile thing to do is to mount the power supply board in the same chassis as the phono board. Keep the transformer outside the phono-stage chassis in its own box and come into the phono-stage with AC power and rectify it at the point of use while making sure to keep the wires connecting the power supply board and the phono stage as short as possible. Taking the additional step of placing the power supply board in the same chassis as the phono board lowers the the power supply impedance even further.
The phono-stage circuit should show improved transient response, better bass, improved dynamic contrast and superior imaging with an increase in the size of the sound-stage from these changes to how the kit is executed.
Scotty

Nick77 · « **Reply #13 on:** 23 Mar 2014, 10:14 am »

Quote

I built the Boozhound PS today. I just need to finish the case and wire it all up.

Looking good, do you have your new table yet? I would be trying one of these kits if i hadnt already built a diyaudio Paradise.

jtwrace · « **Reply #14 on:** 23 Mar 2014, 12:44 pm »

Quote from: *Scotty* on 23 Mar 2014, 06:42 am

Some simple changes as to how the kit is implemented might yield an audible improvement in the sound of the kit. Replace the 3amp Schottky diodes with 6 amp rated Schottky diodes. Mount the the circuit board on 1.5in tall standoffs in an enclosure that has at least a 3 inch high internal dimension.
Doubling the amperage rating on the diode bridge makes a valuable reduction in the power supply impedance. Increasing the space above and below the circuit board to 1.5 inches is virtually the same sonically as mounting the circuit board in a plastic chassis without the RF problems. You could also up the the transformer to a 150VA rating,once again to lower the power supply impedance. I use a 225VA rated transformer and a 15amp rated Schottky diode bridge.
One more worthwhile thing to do is to mount the power supply board in the same chassis as the phono board. Keep the transformer outside the phono-stage chassis in its own box and come into the phono-stage with AC power and rectify it at the point of use while making sure to keep the wires connecting the power supply board and the phono stage as short as possible. Taking the additional step of placing the power supply board in the same chassis as the phono board lowers the the power supply impedance even further.
The phono-stage circuit should show improved transient response, better bass, improved dynamic contrast and superior imaging with an increase in the size of the sound-stage from these changes to how the kit is executed.
Scotty

Interesting. I built this PS for something else but might go ahead and build the phono stage too. I'm still shocked after hearing this phono stage at my friends house.

I used this transformer so I could run it at 12Vdc output. I thought that was overkill but guess not! I also did change R3 to 1k Ohm.

WireNut · « **Reply #15 on:** 23 Mar 2014, 03:27 pm »

You think the Boozhound would be an improvement over my Vista phono pre?
It’s one of the moving magnet ACLE units Boris built for AC members.

Folsom · « **Reply #16 on:** 23 Mar 2014, 04:43 pm »

As it's stupid simple, it should get clean power.

Have any of you seen the DIY Pass one? It's $200 just for PCB. How much better is it, or isn't it? Great question.

The best trick I've found to make a phono stage good is to put in LDR's on the input. Short of nude Vishays maybe, you can't touch it.

On the Booze I just built for a friend, I replaced signal resistors with PRP, but Dale RN55 or whatever are fine. The power caps stock are one of the best, and the RIAA and signal caps are personal choice if you like Russian PIO.

wushuliu · « **Reply #17 on:** 23 Mar 2014, 04:56 pm »

Curious how it compares to the Bugle.

Folsom · « **Reply #18 on:** 23 Mar 2014, 10:30 pm »

I'll compare to Bugle 1 later tonight.

Folsom · « **Reply #19 on:** 23 Mar 2014, 10:36 pm »

I can't make my iphone or gallery photo make that upright... Sorry.