Gday Sy,
Still haven't heard from Mr Gregory, will email again to be sure, anyway, asa thought, had you looked at the 6N2P tube? If the D3a is all over the shop, not sure the sound or ease of use, im sure you would know by looking at it.
Also, if I wanted to get a balanced output, what's the process here?
Thanks,
Drew.
Still haven't heard from Mr Gregory, will email again to be sure, anyway, asa thought, had you looked at the 6N2P tube? If the D3a is all over the shop, not sure the sound or ease of use, im sure you would know by looking at it.
Also, if I wanted to get a balanced output, what's the process here?
Thanks,
Drew.
Easiest way to get a balanced output is to use a transformer. Otherwise, you're looking at adding another stage. IMO, balanced brings nothing to the table between preamp and power amp for home installations.
Many, if not all phono preamps for MC have switchable loading resistors. I'm curious, is that not needed in your opinion, or is there something about the design that makes this unnecessary?
My experience with low output MC is that they tend to be very noncritical of loading. If you do want to play with that, do it on the primary side of the input transformer.
I just inherited a nicely built up HMN that a a late friend of mine did last year before he passed.
He built it up with Jensen JT-44K-DX transformers, but he did not add the Jensen recommended Zobel after the secondary.
http://www.jensen-transformers.com/datashts/44kdx.pdf
Now, I have these same transformers in a standalone SUT I have used for years with various carts (with varying degrees of success), and it uses the recommended implementation.
In the HMN w/o the Zobel , the sound is very bright and the bass is very thin in comparison - which is consistent with what I have read should be the case in this type of standalone implantations of the JT-44K-DX w/o it.
Do you forsee any issues in adding this immediately after the tx secondary in the HMN?
He built it up with Jensen JT-44K-DX transformers, but he did not add the Jensen recommended Zobel after the secondary.
http://www.jensen-transformers.com/datashts/44kdx.pdf
Now, I have these same transformers in a standalone SUT I have used for years with various carts (with varying degrees of success), and it uses the recommended implementation.
In the HMN w/o the Zobel , the sound is very bright and the bass is very thin in comparison - which is consistent with what I have read should be the case in this type of standalone implantations of the JT-44K-DX w/o it.
Do you forsee any issues in adding this immediately after the tx secondary in the HMN?
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No, I don't see an issue- if you want to be thorough, load the transformer with the proposed Zobel and ~100pF in parallel, then drive it with a square wave from a source impedance equal to the DCR of your cartridge at 0.1mV or so (a resistor voltage divider is your friend here!). See what the square wave looks like.
While you're at it, double check that the EQ components are all correct.
While you're at it, double check that the EQ components are all correct.
"While you're at it, double check that the EQ components are all correct."
This may be beyond my nascent abilities. See the attached pics that show a break in the traces on the board adjacent to C7. From the wiring coming from the output end of the board, it looks like the two boards on the end of the chassis have been inserted into this break point.
I will have to figure out what these are for.
Any ideas?
This may be beyond my nascent abilities. See the attached pics that show a break in the traces on the board adjacent to C7. From the wiring coming from the output end of the board, it looks like the two boards on the end of the chassis have been inserted into this break point.
I will have to figure out what these are for.
Any ideas?
Attachments
OK, so the photos I attached earlier didnt show up. You can see them here - Flickr: gortnipper's Photostream
Hey there...
I'm a bit new to this of thing... I've read the article several time and I love the sounds of this project! I'm just wondering if I could build this for a mm cartridge, and skip the need for a step up transformer? If that would indeed work, would I have to make any further modifications? Apologies if this is a rudimentary question, and thanks in advance for any advice.
I'm a bit new to this of thing... I've read the article several time and I love the sounds of this project! I'm just wondering if I could build this for a mm cartridge, and skip the need for a step up transformer? If that would indeed work, would I have to make any further modifications? Apologies if this is a rudimentary question, and thanks in advance for any advice.
Two caveats: first, you obviously lose the advantages of the balanced input. Second, the input capacitance is quite high, which some MM cartridges tolerate and some don't.
Thank you! I'm not terribly concerned with the balanced input since my interconnects are very short and of good quality. However I did not take into account the difference of capacitance... Am I correct in thinking that a mismatch might compromise the tone? To solve this, is it safe to assume I would have to find a different tube with the right input capacitance for a mm? If I left the circuit as is, would a mm in conjunction with the SUTs overdrive the first input stage? I'm beginning to think I ought to just buy a mc!
The problem will remain for just about any high mu triode because of the Miller Effect. If you want to experiment, you could play around with conversion of the first stage to pentode (the noise goes up but for a D3a, it's still pretty low), but that's getting into advanced territory.
Any owns a Pass Xono & His masters noise
Hi there, as so much attention has been drawn to this (very nice) article I 'd like to ask simple question:🙄
Anyone owns Nelson's Xono and His master noise and has compared the sound?
Xono is a hugh step to any pre I had especially in terms of dynamic its like comparing an "cassette player dynamic to CD".
How is this pre sounding?
I'm interested as I built Xono for my friend and I'm so blown away about the musical improvement that I thought about building one for myself. But maybe this pre is interesting too!
Thanks Jochen
Hi there, as so much attention has been drawn to this (very nice) article I 'd like to ask simple question:🙄
Anyone owns Nelson's Xono and His master noise and has compared the sound?
Xono is a hugh step to any pre I had especially in terms of dynamic its like comparing an "cassette player dynamic to CD".
How is this pre sounding?
I'm interested as I built Xono for my friend and I'm so blown away about the musical improvement that I thought about building one for myself. But maybe this pre is interesting too!
Thanks Jochen
Very, very nice article. It in now In my lists of plan to build one day soon.
Thanks to the author!
Thanks to the author!
Hello SY, last question on this: would a high output mc rather than a mm solve any of the problems you mentioned with bypassing the sut's?
Thanks.
Thanks.
Hello SY,
First, a small correction of sorts:
I was wondering if you had advantageous reasons for placing the common mode choke here, as it seems elsewhere that common mode chokes are being used between the regulators and load.
Thanks for the great article, I look forward to building one!
Best regards.
First, a small correction of sorts:
should read:
Code:
"With," not "instead of." I'd put it between the raw supply and the regs.I was wondering if you had advantageous reasons for placing the common mode choke here, as it seems elsewhere that common mode chokes are being used between the regulators and load.
Thanks for the great article, I look forward to building one!
Best regards.
Putting the choke after the regulators increases the supply source impedance. That doesn't strike me as a good thing!
Thanks for spotting the typo. I've been finding a few here and there and editing them out, missed that one completely.
Thanks for spotting the typo. I've been finding a few here and there and editing them out, missed that one completely.
A masterpiece amplifier and article!! Thank you! I learned a lot and will build something similar with 6N17-B, just for fun. Will 7806 regulators for heaters be a problem for noise? Regards, JJ
Shouldn't be a problem, but make sure to use complementary regs as shown here for common mode noise reduction.