Hi, nice to hear that you fixed it and you like the sound.
Use wire jumpers instead of 1.4Ω. If no hum or other noises will appear, you may even leave them there.
What is the rest of the audio system?
As for the eyes, its normal, the lens inside starts stiffening after the age of 40 and doesn't bend as much as it used to, not focusing well on short distance items or pieces of work. But reading glasses and other things do the trick for us. We are well geared up in the modern world. Just imagine a classical age master artisan or top technician mature and recognized, ready for his greatest work yet, but there came a blur. Bummer! Glass lenses hadn't been invented yet.
Use wire jumpers instead of 1.4Ω. If no hum or other noises will appear, you may even leave them there.
What is the rest of the audio system?
As for the eyes, its normal, the lens inside starts stiffening after the age of 40 and doesn't bend as much as it used to, not focusing well on short distance items or pieces of work. But reading glasses and other things do the trick for us. We are well geared up in the modern world. Just imagine a classical age master artisan or top technician mature and recognized, ready for his greatest work yet, but there came a blur. Bummer! Glass lenses hadn't been invented yet.
For what its worth , IIRC this is about to be the first time I've tried different cartridges with this phono pre and I have a question. I've had a basically barely broken in Ortofon Super OM30 sitting in a drawer. Mounted it up and it was dead! Slight rushing noise was all. Unmounting it. one of the posts remained in the lead, so I guess this is where problem lies. Bought new Super OM 5 body online, put the two together and back in business. Having been using a SAE HO moving coil I needed to change settings on phono section and retune to 4.0 volts on the - and + test points.
I thought I remembered mainly setting this with pot on the phono board, and re adjusting B+ voltage to accommodate getting to 4.0.
Well I tried, but the pot on phono board doesnt seem to affect anything. B+ was 33.5ish with the HO MC, by adjusting it down to 30.4ish I got the 4.0 reading I needed. Exact same thing with second board. Then it occurred to me, "maybe I am remembering wrong, and only pot on board does adjustment" and at same time wonder what setting I jacked up twiddling the phono section pot!
Does TP adjustment to 4.0 volts use both pots, and if so why isnt my pot on phono board affecting it? and if both not used, what setting did I screw up?
A little later I will be redoing all this to fit another new cartridge, Audio-Technica AT33PTG/II that I am excited to try, so if I have a problem with a pot or its associated circuit here I would like to get that addressed.
Thanks for any help, going back in thread to find where I built mine, surely I was asking back then! I'm making a small instruction sheet with a couple notes to stick on inside of top cover.
Russellc
I thought I remembered mainly setting this with pot on the phono board, and re adjusting B+ voltage to accommodate getting to 4.0.
Well I tried, but the pot on phono board doesnt seem to affect anything. B+ was 33.5ish with the HO MC, by adjusting it down to 30.4ish I got the 4.0 reading I needed. Exact same thing with second board. Then it occurred to me, "maybe I am remembering wrong, and only pot on board does adjustment" and at same time wonder what setting I jacked up twiddling the phono section pot!
Does TP adjustment to 4.0 volts use both pots, and if so why isnt my pot on phono board affecting it? and if both not used, what setting did I screw up?
A little later I will be redoing all this to fit another new cartridge, Audio-Technica AT33PTG/II that I am excited to try, so if I have a problem with a pot or its associated circuit here I would like to get that addressed.
Thanks for any help, going back in thread to find where I built mine, surely I was asking back then! I'm making a small instruction sheet with a couple notes to stick on inside of top cover.
Russellc
Hi, the trimmer on the psu wing for the rail level is the main one to fiddle with while the one on its attached phono board works like a Vernier to it.
My suggestion is get the Vernier to half turns first and start hunting TP with the main one. Use the Vernier in each channel afterwards just for trimming out tolerances between channels. So to be keeping rail level same on both.
My suggestion is get the Vernier to half turns first and start hunting TP with the main one. Use the Vernier in each channel afterwards just for trimming out tolerances between channels. So to be keeping rail level same on both.
I looked at that one too, probably should have picked up that one. I do tend toward lush, second harmonic distortion, etc.
Somehow I talked myself into thinking this one would be like that, with more bass. Oh well, you cant have too many cartridges!
Oh, back to TP setting. I think with this higher output cartridge, that pot doesnt have much role, I guess it had a little more with the HO MC, and more yet with the AT33. And just to show how thick I can be...Even more confused with "half value, middle position" You mean of the total TP measurement, like 2.0 or so, and then go to 4.0 via pot on power supply? It sounds great by the way!
I may have to snag the Red one....IIRC what steered me most to the PTG/II version was the boron cantelever and the line trace type stylus, vs the duraluminum and shibata stylus. Same thing that pushed me away from the Hana (750.00 version). Well, higher price too I guess! Maybe I should rethink this...I think I will be fine with this one, cant have too many.
Somehow I talked myself into thinking this one would be like that, with more bass. Oh well, you cant have too many cartridges!
Oh, back to TP setting. I think with this higher output cartridge, that pot doesnt have much role, I guess it had a little more with the HO MC, and more yet with the AT33. And just to show how thick I can be...Even more confused with "half value, middle position" You mean of the total TP measurement, like 2.0 or so, and then go to 4.0 via pot on power supply? It sounds great by the way!
I may have to snag the Red one....IIRC what steered me most to the PTG/II version was the boron cantelever and the line trace type stylus, vs the duraluminum and shibata stylus. Same thing that pushed me away from the Hana (750.00 version). Well, higher price too I guess! Maybe I should rethink this...I think I will be fine with this one, cant have too many.
I mean if its an 1kΩ trimmer set it at 500Ω.
The duraluminum cantilever with Shibata or nude elliptical models tend to sound easier across more records. The boron with line contact models are more exact but maybe bit more lean. There are also duraluminum or simple aluminum ones with line profile diamonds. Classic examples are the Dynavector 20X2 and the Hana ML. The Hana SL is a good cart but its lighter in mass and has higher Zout at 30Ω (also 0.5mV output which is useful) than the 10Ω class 0.3mV AT33s. Better not load an SL with less than 400Ω and check if it needs extra mass plate for lowering tonearm resonance in other words. I personally have a PTG/II and its a great value cartridge no doubt. Its linear sounding for sure although calm enough not as bright as an OC9. But not suave either.
The duraluminum cantilever with Shibata or nude elliptical models tend to sound easier across more records. The boron with line contact models are more exact but maybe bit more lean. There are also duraluminum or simple aluminum ones with line profile diamonds. Classic examples are the Dynavector 20X2 and the Hana ML. The Hana SL is a good cart but its lighter in mass and has higher Zout at 30Ω (also 0.5mV output which is useful) than the 10Ω class 0.3mV AT33s. Better not load an SL with less than 400Ω and check if it needs extra mass plate for lowering tonearm resonance in other words. I personally have a PTG/II and its a great value cartridge no doubt. Its linear sounding for sure although calm enough not as bright as an OC9. But not suave either.
Well I dont think I will regret having this, but had I know this at the beginning, I might have gone that way. Probably still will? My current arm has an option to increase mass, some piece in the box that screws on the back, I need to have a look at that. If I get a Hana it would be the ML version
The Hana ML is heavier than the SL already, has Alnico magnet and an extra top plate. Plus it has 7 Ohm 1kHz Zout vs 30 Ohm of the SL but still achieves 0.4mV output which is 25% more than the 10 Ohm 0.3mV AT33s. And we know its a popular cart. Probably the mix of magnet type, body damping, aluminum cantilever but with microline stylus, is well judged. The 33EV is still the obvious value for money kid of the lot. Followed by the PTG/II. Microline tip profile is supposed to last significantly longer than elliptical though. Somewhat more than Shibata also. Due to its finer contact with the groove.
Oh no, it was on the way when we first spoke.
Hooked it up yesterday. Very impressed, I shouldn't have worried. 100 ohms and 220 pf I believe is where phono preamp is set.
I feared it would lean thin and nothing could be further off, nice and warm presentation. Not lush, but far from thin, strong bass
It's the 33 ptg /2 version, not the red one
Hooked it up yesterday. Very impressed, I shouldn't have worried. 100 ohms and 220 pf I believe is where phono preamp is set.
I feared it would lean thin and nothing could be further off, nice and warm presentation. Not lush, but far from thin, strong bass
It's the 33 ptg /2 version, not the red one
Its the other way around indeed. What the secondary VR essentially does is trimming the input stage's current source resistor's value (R13-R16). To aid finer current balance in the folded cascode branches. Since there are tolerances mainly in the JFETs it can be used to fine tune T.P. while keeping the appropriate B+ voltage same between channels with the main VR. In MM due to higher resistive values and less bias current, the secondary VR plays a much reduced role. It is 1k VR but it only spans 500 Ω as it is in parallel with the 1k R12. In MC & LMC modes with their smaller current source and degeneration resistances it obviously takes more part in the setting.