They have a 5.1 decoded output and jacks or the dedicated 2 channel output. I only care about the dedicated 2 channel output. That way it doesn't even go through the surround sound decoding chip. I didn't measure the height but the diameter of the Silmic's is 10mm with a 5mm pitch.
Oh, OK, the Silmics are a little bigger, but 10mm diameter is still pretty small, I thought they were bigger from the picture, may be tight to get most decent 5uF film caps in there, but may be able to find some skinny long ones that would work for a listening test.
BTW, I've noticed a few (RJM Very Simple Phono Stage, Grado PH-1, etc.) single op amp phono stages don't use that large cap in the feedback loop at all. But it seems like the price you pay is some DC offset, making the output coupling cap or an input coupling cap at the next stage pretty critical. But I've read that this DC offset will reduce the maximum output of the op amp, which seems like a high price to pay when you're relying on a single op amp for everything? Yet the Grado PH-1 has a gain switch that allows for up to (I think) 50 or 57dB depending on which schematic you're viewing. And as simple as that design is, they have quite a few fans.
Yea, it's possible, depends on the opamp and the input circuit. I don't know which opamp Grado uses, don't they remove the labeling? But you're right, the schematic I see someone posted online doesn't have any DC filter in the feedback. The schematic shows 53 ohms for the high gain position, so you would need a pretty big filter cap, probably a few hundred uF at least for a decent low end response.
Yep according to LTSpice, it would take about 300uf to maintain a decent LF response. It would be interesting to measure one of these Grado units and see just how much DC offset they're generating. Don't some op amps like the JRC4556 (what is rumored to be in the Grado) generate less DC offset than others?
Yes, mainly the input circuit and what type of transistors are used. Bipolar transistors can have some base leakage current, so that can unbalance it. Many of the JFET opamps are very precise and can be used without a DC filter since there is no significant gate leakage, so not too hard to make a DC coupled design.
Just powered up and listening to my DIY FE 2022 preamp, designed by Nelson Pass. Packaged it up to match my Darlington Labs MP8B. Still to do: Add 3mm blue power-on LED Counterbore front panel then anodize black to match my Darlington Labs MP8B Replace AN 100K pot with TKD 2CP-2511 10K unit. Experiment tapping into my amp for 44VDC to replace 48VDC SMPS Sounds better than it has any right to. DIY is fun.
Hello Jaytor. Sorry to post here but I am dying to ask you for a oarts list for the Balanced Preamp you posted in 2021. The title of the post was DIY Fully Balanced Preamp It looks amazing and I would love to be able to make one myself. Please let me know if that is okay with you. Please message me here or email me [email protected]. Thank you!!!
Moving on from my previous posting, I have been evaluating and tweaking the set up of my new DIY top board. I’m beginning to understand that my previous aversion to MDF was really just an aversion to my original standard Xerxes top board with it’s resonant characteristics. MDF on it’s own is probably ok when resonance is reduced as much as possible, and such harmful resonance is also less likely if the material used in a turntable is of thicker section as in the 40mm or so of MDF you see in some better budget / mid price decks today? This old iPad is currently preventing multiple image posts so I will have to explain my experiments in stages. I switched my new top from my ‘three tier’ chassis to the original ‘two tier’ Xerxes Mk1 base as shown above. Amazingly the resolution jumped up to yet another level in spite of using the less sophisticated chassis. I can only conclude that my DIY three tier chassis (which is based on the TMS 1 design ideas) IS good at countering the resonances and colourations in the original Xerxes MDF Top, but was somehow limiting my new beechwood/MDF top plate above! My DIY three tier isolation towers did introduce two extra neoprene washers as spacers below the domed isolators. I had also used softer rubber foot pads as opposed to the standard hard plastic conical feet, but maybe these were allowing too much give and that the harder feet of the original deck gave the early Xerxes some of its clean sound characteristics? Whatever, listening to some of my records on the above set up was a minor revelation in resolution. The flute in Moody Blues ‘Timothy Leary’ sent shivers down the spine. Susan Vega’s ‘Toms Diner’ was the most natural sounding yet, and King Crimson’s ‘I talk to the Wind’ was simply haunting! .....and yet there is a problem; good recordings sound wonderful with more ambience around each sound. Vocals are more real, deep bass goes very deep and high voices reach for the sky, but there remains some mid bass lightness, which is holding back some recordings. to be Continued.......
Before switching to my two tier chassis I wanted to improve the Beech/MDF board by examining it’s resonant properties. I did another ‘salt test’ by sprinkling granules all over the board and fixing the board to a worktop with motor induced vibrations. After 20 minutes or so the salt granules had gathered into a banana shaped oval between the main bearing area and the arm mounting point. This gathering of granules is on the area of least resonance within the top board, and therefore I reasoned that removal of material under here would make least difference to the board while at the same time would take away the possible ‘ over damping’ effect the MDF had on the sound? I shallowed out the MDF layer under the top board with my belt sander, which resulted in the ‘moonscape’ shown below. On audition the mild suck out of the bass is still apparent, but I am making a complete new set of chassis parts of thicker MDF section with which I hope to determine by substitution what elements in these decks is causing any imbalance and the mid bass reduction.
Below is a new chassis base board in progress for a two tier deck made up from 28mm beech and 12.7 mm MDF. The domed isolators will be supported from below with TMS domes bolted into threaded inserts. The rear top board support isolator can be seen in situ in the nearest hole. Another equally solid matching top board will be made to make comparisons with my current ‘star’ shaped top!
Thanks for the support. No to a CNC router, just an old hand held relic and DIY jigs! If I had any sense I would go out and buy a really good turntable instead.
Anyone know where I can buy some cordless electric clamps? Veneered all 4 sides of this cabinet yesterday and at my age, twisting/untwisting those handles, everything hurts this morning.
Cordless clamps, think you may have invented a new product there, mind you imagine having to keep them all charged.
Ya got me to thinking that 10 years from now, when I'm 86 and really feeble, making new hexagonal handles to use with a deep socket Hex bit and the big Milwaukee drill will be the way to go
Decided to use some scrap birch ply and walnut veneer I had left over from another project and build a plinth for my Thorens TD126 Mk II. While I was at it, I installed a stainless steel top plate and a Schopper arm wand to provide some more mass to my tonearm so it's a better match for my mono cartridge. Only my second time doing any veneer work, so not perfect but I'm happy with it.
There are newer clamps that you pull a lever and slide the clamp to where you want it and there is a trigger that you squeeze to fine adjust into place, works very well. I bought these at Lowes. Fast and easy to use. like these in the pic.
I have a pair of those for use as a third hand but I find they move the work as they tighten so won't do for veneering or cutting miters. I even bought the Bessey version, very expensive, and it's an absolute POS. The Bessey Parallel Jaws, though, are worth every penny of the large investment.
Really? I haven't had that issue but to be honest I have only use them for holding the wood together while predrill the holes and gluing the cabs together. I will find out how good they are when I do my veneering.
Not a big one, but necessary. I have a short IEC cord and the TT comes with the nice JDM 2 pin Luxman cord. The TT comes with a cheap plug in xfmr but from reading the V out when on 120 is >105, not a big deal but it appears to be a toroidal auto xfmr. In addition it is over sized, 135 VA, load is <10 VA. The 40 VA with a peaking factor of 4 should be a good fit. 2 winding, I can make it isolated, Whichever way has lower noise will determine that. I have a 1 A/10 A limiting for the primary.
