Never change one tube type for another without adjusting the peripheral parameters of the circuit.
But anyway, just bypass R9 and you will have more gain at your output. Maybe thats sufficient.
Yet another solution to the OP's problem is selling the Denon cart. off and acquiring a true HOMC device, such as this Ortofon model.
ECC81 is a VHF double triode not an audio designed tube but that didn't stop "tube rollers " in headfi.org as I found to my cost when I pointed out the differences I was shouted down .
I do not subscribe to the policy of using tubes like VM types which are specially designed for RF applications in AVC for use in audio although the ECC83 isn't VM it potentially can have instability problems when used in some audio circuits .
I left years ago as my interest was in Stax only.
I do not subscribe to the policy of using tubes like VM types which are specially designed for RF applications in AVC for use in audio although the ECC83 isn't VM it potentially can have instability problems when used in some audio circuits .
I left years ago as my interest was in Stax only.
RFT data sheet (translated) : ECC82, double triode with separate cathodes for oscillator and multivibrator circuits in tv sets and for electronic calculators and counters ..
Of course it can be used for audio and has been used even in professional equipment. Why should it be unsuitable for it?
Best regards!
Correct, also all Dynacord stage amplifiers with two or four EL34's used it as PI. And I know of amplifiers that used EC92's (half of a 12AT7/ECC81) in their microphone input stages. And Philips used the ECC85, a double triode dedicated for VHF/UKW frontends and very similar to the ECC81 datawise, as a LTP PI in their EL6415/EL6425/EL6435 public adress amps.
Why should a tube be restrained from amplifying audio LF?
Best regards!
Why should a tube be restrained from amplifying audio LF?
Best regards!
I partly agree with you. It looks like a resistor to a virtual ground to me, but probably a rather poor virtual ground due to the limited transconductance of the EF86. A lower resistor will reduce loop gain of the feedback around the EF86 and probably make the RIAA response less accurate. It also reduces noise and increases gain.
Attenuating the line level signals would be my preference.
This is why I wrote "frequency response will be even worse with increased gain of this stage".
Does the OP use an Elektor pcb ? https://worldradiohistory.com/UK/Elektor/00s/Elektor-2003-09.pdf page 8 ff
Does the OP use an Elektor pcb ? https://worldradiohistory.com/UK/Elektor/00s/Elektor-2003-09.pdf page 8 ff
Too much signal is seldom difficult to reduce 🙂
A transformer is a clean simple and well soundig device that is easy to revert.
A good sounding transformer isn't cheap. But this preamp is. So I think it wasn't the intention to buy something for solving this problem which is more expensive than the whole preamp.
Elektor did not a good job in presenting this schematic. Reminds me of some mediocre tube preamps of the 1950s-1960. Too much problems and technical not really able to solve some major problems with this one stage phono circuit.
With less parts this could have been done better easily. But those are Elektor audio circuits, they often claim to be better than they really are. In fact its something cheap for someone who want to hear something from its record without buying stock gear. The satisfaction is within the fact that its something, which could be done by DIY (and buying the Elektor PCB). Many then will say: look, this is very good because I build it. But it isn't really. Its just a mediocre design and will never cut the edge. So I think its a waste of money to buy transformers for high cash. High in relative to the whole unit.
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As said similar to Quad 22 .. I am sure it can work satisfactorily .. already discussed that a transformer is not suitable for DL-110 .. but you could as well find cheap signal transformers if considered useful .. Elektor is not about cutting edge but to provide DIY solutions. Many "high end" companies have been founded using Elektor schematics .. why bash the preamp of this user ?
Once I build an Elektor set of a class A transistor power amp.
It was clearly anounced for the clever DIY community to build something which would be a top notch amplifier, costing much more in the stock world of audio hifi. They often do measurements to prove that their sets are excellent compared to more expensive stock units.
Thats their simple marketing goal, should they advertise to offer something mediocre for the community so that everybody knows, I can safe money here by DIY but will never have a good designed unit in the end? That will be self destructive for this mag, because nobody throws money on those projects.
You see, that they promise "excellent results" with this project in their presentation. I don't think the outcome could be excellent but its a relative term.
"As can be seen from the schematicdiagram of the amplifier (Figure 1),no overall feedback is used, butonly local feedback in the phonopreamplifier. This is because valvesare manufactured to such tight tol-erances that excellent results canbe achieved even without usingfeedback."
It was clearly anounced for the clever DIY community to build something which would be a top notch amplifier, costing much more in the stock world of audio hifi. They often do measurements to prove that their sets are excellent compared to more expensive stock units.
Thats their simple marketing goal, should they advertise to offer something mediocre for the community so that everybody knows, I can safe money here by DIY but will never have a good designed unit in the end? That will be self destructive for this mag, because nobody throws money on those projects.
You see, that they promise "excellent results" with this project in their presentation. I don't think the outcome could be excellent but its a relative term.
"As can be seen from the schematicdiagram of the amplifier (Figure 1),no overall feedback is used, butonly local feedback in the phonopreamplifier. This is because valvesare manufactured to such tight tol-erances that excellent results canbe achieved even without usingfeedback."
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They ain't bad up to 10mV or 20mV peak.
A MC needle is below that. This hot MC needle peaks right at that level.
The distortion beyond 10-20mV is not immediately awful, not clipping, just mildly bent.
Yes, that plan makes me ill. It works out to <35uA for a 100r source, the noise figure is way-high. But NF isn't everything in vinyl. And the big argument: it is $1.27 of parts. Plus an Altoids tin or other *metal* box. I think he may as well build it, even though there is 'room for improvement' every which way.
I built the little head amp and it works okay. The real problem is the ELektor phono stage. It sounds really bass light. I may be flogging a dead horse here. Can I tweak the RIAA for more bass?