No, but it’s risky because you might plug in a preamp one day that is not zero offset. Do you dislike input coupling caps that much?
I haven’t built the AX14 but it may sound similar to AX13 as both front ends were designed by Apex Audio and have same LTP topology with NPN BJT. The AX14 OTOH has a different input topology of balanced PNP’s and I think a current mirror? It also had BJTs on the output. In general, a MOSFET output will have more muscular sounding bass.
If you are currently building an FH9HVX and running into issues, please post questions here vs working via PM with me. The community here is great for debugging. We will need some good closeup photos from different angles to see the parts clearly and how they are soldered. Oblique angles are better than straight shots from above. Also provide DMM measurements of all voltages at all pins of all actives relative to GND. Mark that up in red ink next to the part on the printed paper schematic and take a photo of that marked up schematic. That is hard work to get those points. But will help to positively identify the problem if it is a DC setpoint problem like no bias current, or massive DC offset.
X, this getting close to be a product in the Etsy store?Hi Legis, glad you got to try the tube buffer. Nice combo of warmth and bass grip all at the same time.
There are a lot of similar things around for budget tube buffers. The trick is finding one that is quiet. I have tried at least 4 of them in the $40 to $70 range and all had some noise. I finally had to ask Jhofland to design one for me - all DC/DC converters and powered from a 12v wallwart. It sounds superb. Basically an ECC88 interstage buffer inside a BTSB.
This will be available soon as a commerical product.
However, in my search for a quiet tube buffer, this one came close - and has a basic DAC and Bluetooth as well.
Thanks, Pete
I would also be interested. Been looking at tube buffers for a while now. They seem such simple circuits, but with glowing (no pun intended) reviews.
Interest noted. Thanks for letting me know. It’s quite an involved SMD build with more than 300 components. I don’t think most people have the stomach or ability to handle something like this as DIY. So if I do offer it, it would have to be a ready to run module. One thing I am dealing with right now is a major parts shortages and so we had to buy components many months in advance for a commercial run. There are not enough parts to make a second run at present. The killer is always specific DCDC converter chips, optoisolators or low RDson MOSFETs.
Here is the latest version with built in open collector logic to control associated amp graceful turn on / off without thump.
Or you can wait until about June this year and a combined tube buffer and headphone amp with triple input select will be commercially available for $795. This is called the HyperDrive-2. It will have dual RCA outputs in addition to headphone outs.
Here is the latest version with built in open collector logic to control associated amp graceful turn on / off without thump.
Or you can wait until about June this year and a combined tube buffer and headphone amp with triple input select will be commercially available for $795. This is called the HyperDrive-2. It will have dual RCA outputs in addition to headphone outs.
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SMD doesn't worry me at all. I enjoy it, like Vunce, and others...keep us in mind
; just a PCB and detailed schematic - BOM's can then be generated and so on.Best,
Anand.
turion64,
I really doubt the cost difference will be much between one these fully built boards (which has a large # of SMD parts & small number of through hole parts) and one that has just SMD. So from a cost standpoint for you & for X, there wouldn’t be much if at all. From an inconvenience standpoint it will be more to stock 3 different versions (bare pcb, partially assembled, and fully assembled).
There is also something else to consider. The headaches in debugging a poorly assembled SMD design on the part the novice diy’er. That takes patience and time. Some folks really enjoy that process, others, not so much.
I am surprised however with how patient many of the manufacturers on diyaudio are including XRK. It’s X’s call of course, just my $0.02 after observing others in the industry who have tried to offer multiple different assembled iterations of a pcb and the headaches they’ve had to overcome.
Best,
Anand.
I really doubt the cost difference will be much between one these fully built boards (which has a large # of SMD parts & small number of through hole parts) and one that has just SMD. So from a cost standpoint for you & for X, there wouldn’t be much if at all. From an inconvenience standpoint it will be more to stock 3 different versions (bare pcb, partially assembled, and fully assembled).
There is also something else to consider. The headaches in debugging a poorly assembled SMD design on the part the novice diy’er. That takes patience and time. Some folks really enjoy that process, others, not so much.
I am surprised however with how patient many of the manufacturers on diyaudio are including XRK. It’s X’s call of course, just my $0.02 after observing others in the industry who have tried to offer multiple different assembled iterations of a pcb and the headaches they’ve had to overcome.
Best,
Anand.
Understood and reasonable X & Anand. I don't mind a small amount of SMD work (by hand) but as soon as the part has contacts under the component, and you can't see if the pads have soldered correctly, one's level of certainty about proper construction drops significantly. I guess we'll wait for a fully assembled board's arrival into the Etsy sale website.
Cheers, Pete