Dubious 2SK117GR
Check your 2SK117GR stash if you recently bought any. I have caught a circulating specimen that presents wrong curves (not flat but diagonal). It invariably has GR OK batch number printed on it. Its IDSS, Yfs, Vgs may appear in range and it will work (maybe will bias lower under small VDS) but surely it will not perform OK dynamically.
In general, proper 2SK117GR should have "one" digits printed like vertical featureless lines, should show a short prominent ridge along the center front when viewed from top, show a bit of copper color when viewed from the back where the pins enter the plastic. Much like 2SK170BL.
I alerted tea-bag about it and he investigated his stash. He found a number but he received those very recently and he could have sent out only about 80 pcs most likely in BIB 1.1 bags not in FSP bags. If you spot those bad apples let him know via PM. Do check the new FSP mini-kit arrivals nonetheless or whatever 117s you bought yourself from vendors especially recently.
Check your 2SK117GR stash if you recently bought any. I have caught a circulating specimen that presents wrong curves (not flat but diagonal). It invariably has GR OK batch number printed on it. Its IDSS, Yfs, Vgs may appear in range and it will work (maybe will bias lower under small VDS) but surely it will not perform OK dynamically.
In general, proper 2SK117GR should have "one" digits printed like vertical featureless lines, should show a short prominent ridge along the center front when viewed from top, show a bit of copper color when viewed from the back where the pins enter the plastic. Much like 2SK170BL.
I alerted tea-bag about it and he investigated his stash. He found a number but he received those very recently and he could have sent out only about 80 pcs most likely in BIB 1.1 bags not in FSP bags. If you spot those bad apples let him know via PM. Do check the new FSP mini-kit arrivals nonetheless or whatever 117s you bought yourself from vendors especially recently.
My turntable and cartridge
Dear SALAS,
I think my table is good.
An amalgamation of parts with years of evolution.
Starting with a 50hz LENCO L75 all that remains is the motor, idler arm, and the bearing spindle.
A REINDERS top plate atop an OSWALDS MILL oversized slate plinth - there is area behind enough to place the phono stage to minimize distance from the cartridge to the input. I use a single length of CARDAS tonearm wire from the cartridge to the phono amp. AS short as possible.
The bearing is a MIRKO titanium bearing. I also have his titanium idler wheel.
The platter has two big O rings around it (inspired by ORACLE) and atop that are 5 of TTWEIGHTS copper mats - the top one having the carbon fiber mat on top. Plenty of mass and the layers add damping. A TTWEIGHTS record weight finishes off the load I put on the bearing's thrust plate. A length of wooden dowel is needed for a spindle because of the height of the platter mats.
The motor has had a ceramic ball bearing installed where the nose screw is (I think I am remembering the name correctly, if not LENCO folks will know what I mean). There is also a copper plate epoxied to the bottom of the motor for added mass and added stiffness of the motor frame. Suspension springs adjusted accordingly.
A PS AUDIO P300 gives me the 50 hz AC.
The tonearm is an EMINENT TECHNOLOGY that has a longer than stock length carbon fiber arm (to clear the TTWEIGHTS peripheral platter weight). The arm uses what Mr. Thigpen calls the low pressure high volume manifold which requires a full size air compressor (outside of the house). The arm has been stripped of its mounting hardware which struck me as too loose. The manifold, once the correct height is found, is clamped to the plinth with a piece of ebony under the manifold and above for the clamping. A very large bronze bolt and nut are used for applying pressure.
There is a trough of silicone fluid for damping the tone arm. The paddle is attached to the back of the tone arm. Instead of the short stick for the counterweight which requires a heavy weight to do its job I am using a length of balsa, the same length as the tone arm with a small brass weight for setting tracking force. The weight itself rides slightly below the surface of the LP. This greatly reduces the moving mass of the arm.
The cartridge is a TRANSFIGURATION Temper Supreme that I have used for fifteen years. I sent it to EXPERT STYLUS a couple of years ago feeling sure it was near needing a new stylus and was told the stylus was in excellent condition. Yes, I hope that is taken as a complete and utter endorsement of the excellence and decency of EXPERT STYLUS. I would never send a cartridge to anyone else. So I continue to enjoy this cartridge. I have a back up of a ZU DENON 103 which I listened to while the TTS was on its London adventure. It was OK. When the TTS was returned to duty my ears were very grateful. Maybe I got lucky and got a really good one but I love this cartridge. I could not afford to purchase a replacement of the same quality.
I will get it rebuilt by EXPERT when the time comes.
I use a polarity switch (TUBECAD) at the phono stage with the load resistor on the output side (otherwise you get a big pop). I cannot emphasize enough the importance of listening for the best position. In my system, on most records, there is an obvious best setting. The best setting results in the most spacious sound - the stage extending further out from the speakers.
The table itself sits upon four springs and then on my first LENCO plinth, made Nantais style with alternating pieces of MDF and Baltic birch plywood (probably weighs 150 pounds) then two large spruce beams which allows space for the subwoofer crossover and the PS Audio P300 and then a large "sandbox". The springs are augmented by three stabilizing bits of wood with two having sorbothane squares. Most of the weight is taken by the springs but enough is on the sorbothane for it to work. These bits of wood make levelling the table much simpler. Even though the table is on a suspended floor one has to try very hard to upset the table while a record is playing. I think it is highly isolated from the earth.
Antiskate force is adjusted by the front to back angle of the table's deck. The only way to do this with the ET and it works just fine.
There it is, more than anyone wanted to know!
Dear SALAS,
I think my table is good.
An amalgamation of parts with years of evolution.
Starting with a 50hz LENCO L75 all that remains is the motor, idler arm, and the bearing spindle.
A REINDERS top plate atop an OSWALDS MILL oversized slate plinth - there is area behind enough to place the phono stage to minimize distance from the cartridge to the input. I use a single length of CARDAS tonearm wire from the cartridge to the phono amp. AS short as possible.
The bearing is a MIRKO titanium bearing. I also have his titanium idler wheel.
The platter has two big O rings around it (inspired by ORACLE) and atop that are 5 of TTWEIGHTS copper mats - the top one having the carbon fiber mat on top. Plenty of mass and the layers add damping. A TTWEIGHTS record weight finishes off the load I put on the bearing's thrust plate. A length of wooden dowel is needed for a spindle because of the height of the platter mats.
The motor has had a ceramic ball bearing installed where the nose screw is (I think I am remembering the name correctly, if not LENCO folks will know what I mean). There is also a copper plate epoxied to the bottom of the motor for added mass and added stiffness of the motor frame. Suspension springs adjusted accordingly.
A PS AUDIO P300 gives me the 50 hz AC.
The tonearm is an EMINENT TECHNOLOGY that has a longer than stock length carbon fiber arm (to clear the TTWEIGHTS peripheral platter weight). The arm uses what Mr. Thigpen calls the low pressure high volume manifold which requires a full size air compressor (outside of the house). The arm has been stripped of its mounting hardware which struck me as too loose. The manifold, once the correct height is found, is clamped to the plinth with a piece of ebony under the manifold and above for the clamping. A very large bronze bolt and nut are used for applying pressure.
There is a trough of silicone fluid for damping the tone arm. The paddle is attached to the back of the tone arm. Instead of the short stick for the counterweight which requires a heavy weight to do its job I am using a length of balsa, the same length as the tone arm with a small brass weight for setting tracking force. The weight itself rides slightly below the surface of the LP. This greatly reduces the moving mass of the arm.
The cartridge is a TRANSFIGURATION Temper Supreme that I have used for fifteen years. I sent it to EXPERT STYLUS a couple of years ago feeling sure it was near needing a new stylus and was told the stylus was in excellent condition. Yes, I hope that is taken as a complete and utter endorsement of the excellence and decency of EXPERT STYLUS. I would never send a cartridge to anyone else. So I continue to enjoy this cartridge. I have a back up of a ZU DENON 103 which I listened to while the TTS was on its London adventure. It was OK. When the TTS was returned to duty my ears were very grateful. Maybe I got lucky and got a really good one but I love this cartridge. I could not afford to purchase a replacement of the same quality.
I will get it rebuilt by EXPERT when the time comes.
I use a polarity switch (TUBECAD) at the phono stage with the load resistor on the output side (otherwise you get a big pop). I cannot emphasize enough the importance of listening for the best position. In my system, on most records, there is an obvious best setting. The best setting results in the most spacious sound - the stage extending further out from the speakers.
The table itself sits upon four springs and then on my first LENCO plinth, made Nantais style with alternating pieces of MDF and Baltic birch plywood (probably weighs 150 pounds) then two large spruce beams which allows space for the subwoofer crossover and the PS Audio P300 and then a large "sandbox". The springs are augmented by three stabilizing bits of wood with two having sorbothane squares. Most of the weight is taken by the springs but enough is on the sorbothane for it to work. These bits of wood make levelling the table much simpler. Even though the table is on a suspended floor one has to try very hard to upset the table while a record is playing. I think it is highly isolated from the earth.
Antiskate force is adjusted by the front to back angle of the table's deck. The only way to do this with the ET and it works just fine.
There it is, more than anyone wanted to know!
I chanced on Tunnel of Love and Darkness on the Edge of Town on one of my shelves today so I thought I could listen to One Step Up's bass line you mentioned. No bump up, very spectral with the PTG/II too. What I gathered by experimenting a little is that those new gen AT-33s are sensitive down to 0.1gr VTF differences regarding bass balance. I think you mentioned you have the 33EV set at 2.2gr? If you got a trusty digital scale try to decrease by 0.1gr steps down to 2gr. After you visually know the turn range on the counterweight between 2-2.2 you can slowly move finer than 0.1gr even. There is a point where the bass phrases up and all images they just open up wide and deep. Mine when set heavy sits the image height down noticeably. When correct its like there are no speakers in the room. With your biggish bass reflex speakers it may drag the bass guitar on some not so well mixed recordings if bit heavily set I think. Two Faces song from the same record just before Brilliant Disguise on same side is very good to judge if the 3D presence can gain up. Also after it got kinda broken in by now, 200R load is no problem still sweet but bit more light, its just a matter of synergy with the rest of gear choosing 150R or 200R. When new out of the box, on 200R it could had been a little harsh on some classical records when the brass instruments went loud and high. Not anymore. Alright, that was my report, maybe it can be of help since we got almost the same cart and RIAA preamp.
P.S. I did those things with neutral VTA. (i.e. the arm tube was parallel to the record's surface).
Hi
I have the boards and the components from Tea Bag, but I have some questions.
The 2SK117's have a large spread of Idss from 2.78mA to 5.59mA, I don't have six in the 3-4mA range, it looks like I might need to use three in the 3-4mA and three in the 4-6mA ranges between the two boards, would this be OK?
I'm confused about the values of R2 & R3 in the phono stage. I will populate both Q1 and Q2, but what values to use for R2 & R3? It's not really clear in the notes.
Thanks for the help.
I have the boards and the components from Tea Bag, but I have some questions.
The 2SK117's have a large spread of Idss from 2.78mA to 5.59mA, I don't have six in the 3-4mA range, it looks like I might need to use three in the 3-4mA and three in the 4-6mA ranges between the two boards, would this be OK?
I'm confused about the values of R2 & R3 in the phono stage. I will populate both Q1 and Q2, but what values to use for R2 & R3? It's not really clear in the notes.
Thanks for the help.
Finally got the parts (and the time) to start building the folded using Salas boards....
Been reading the excellent pdf and my first doubt comes from the grounding arrangement.
Pic1 indicates we should connect both psu (shunt) grounds to the case/arm ground fixing....
Pic2 indicates we should use a 1r resistor to connect both psu negatives to the "safety earth arrangement"
I believe we are running into a ground loop here... is it possible ? Or the 1r resistor eliminate that problem ?
Been reading the excellent pdf and my first doubt comes from the grounding arrangement.
Pic1 indicates we should connect both psu (shunt) grounds to the case/arm ground fixing....
Pic2 indicates we should use a 1r resistor to connect both psu negatives to the "safety earth arrangement"
I believe we are running into a ground loop here... is it possible ? Or the 1r resistor eliminate that problem ?
When you haven't got preferable IDSS 2SK117GR for all places it does not mean that you can't use different IDSS if you will understand their functions:
1. Q7 lights up the phono's input section LEDs. Anything 2.6-6.5mA will give them sufficient current. Just keep those Q7 relatively close IDSS between channels. The drop across R15 is calculated for 4-5mA and about 15V drop. You may recalculate R15 for other IDSS at hand although not critical.
2. Q3x IDSS can be any as long as you will calculate there can be enough current for driving VR2x and R3x sufficiently to develop a useful ceiling of about 36V for your ease of adjusting Rail+. The formula should be Rail=((IDSSQ3x*0.8)*(R3x+VR2x))+(0.6+1.85). i.e. The practical way is to alter the R3 value according to your IDSS at hand.
3. Q2x & Q5x have no direct voltage parameter to affect, just local bias thus dissipation in the TO-92s. Better be moderate IDSS and close together enough between channels. If having low and high to choose from, better choose low.
Its not a loop since the signal ground is tied at the main phono chassis directly when the protection diodes are keeping it 10R lifted from the PSU chassis. Which is at mains ground. The 1R are telling the double mono zero lines to prefer the main chassis as ref point between them. But its not a major function. If you will ask an electrician he will tell you that they should not be there at all in case of a very big fault current, so replace those with a zero Ohm link if you are going to use more than 1A primary fuse.
There is nothing to run between them since they are just zero lines, else than current in a fault. Its like paralleling them wires. The main chassis isn't grounding those bcs its otherwise floating, they are the ones giving it zero reference to become a shield. There is 10R also before they see mains ground in normal operation.
Meantime, did rclourenco receive his 10X5 yet, did nezbleu tone down his Denon's hf without resolution loss, did skouliki find the right ketchup to clean his tarnished NOS caps legs? Questions run deep.
The good news is that tracking shows my 10X5 arrived to Lisbon, bad news is that it still is on costumes, will get it for sure middle next week. In the mean time I decided to buy a demo unit with around 100 hours for 300 bucks, which with transportation included was 236€, it seems a nice grab complete with original casing and buying invoice.
Will keep you posted.
PS - this week I tried a small tweaking with C2X, I had silver mica 200pf, and connecteneon parallel one more on each channel, of 27pf silver mica (why 27? Simply because I had them) and the sound seemed more controlled and detailed from top down, with the Dyna, I will try same and other tweaks. As anyone tried Russian FT3 for C3?
The Ortofon 2M RED is rather toned down for treble in my view and entry level for resolution in general. In such a case silver mica can come across like spicing things up. Most MM rely on an electrical tank circuit to bump up beyond 12kHz after a downwards slide in the response. With the 10X5 on just 150 Ohm motor as signal source you will probably find polysterene or tin+polystyrene film & foil smoother and cleaner than silver mica for the C2Y, its value you may need change also. But try both types for yourself since each system as a whole has its own traits. I also have 10X4 MKII and had auditioned 10X5 several times too, they are evenly balanced but not edgy. Resolution and dynamics are much purer than with the 2M RED. Response is naturally extended and flat enough too.