What Pre Amp to go for?

[mikeyb]

Hi,

I am on the lookout for a Pre Amp to go with my EWA M-50 Power Amp. I am currently using Ali's Slagle Passive Pre which is superb, and I can keep as long as I like with the probability of purchase, but I'm wondering if there is anything out there that isn't too expensive ( under £1000 S/H ) that would compete with it, or possibly better it ( not easy I bet ).

Would need to include a minimum of 3 inputs, Headphone out and remote control ( no line of site )

The Croft Epoch I had a short time ago was nice, but the gain was all wrong, I think the M-50 needs 22k rather than 47k, is that right?

Jerry's Bel Canto Pre3 looks good but it has green led screen, but I'm not keen on green lol.

I wonder if it would easier to connect a headphone amp to the Slagle output? Then forget about the remote?

Your thoughts, recommendations much appreciated.

Mike.

[walpurgis]

Why not ask Colin for recommendations?

[mikeyb]

Why not ask Colin for recommendations?
I've heard his Q20 Pre and it's excellent but over my budget. I just wanted to pick a few brains in here, sitting here bored watching the rain and thought I'd ask 😊

[RothwellAudio]

The Croft Epoch I had a short time ago was nice, but the gain was all wrong, I think the M-50 needs 22k rather than 47k, is that right?
I'm not sure what you mean by that. Can you elaborate?

[mikeyb]

I'm not sure what you mean by that. Can you elaborate?
Not really cos I don't understand it, Colin mentioned a figure of 22 when I said the Croft had to be turned almost all the way up to get to semi decent volume, I think he said the M50 likes to see 22 or something, seeing as I don't understand this sort of thing I might be completely wrong lol

[WESTLOWER]

Hi Mike
give David a shout at AD Audio (in the trade section) he is building some serious Pre amps, and you won't find better for the money.
He is very flexible to ones needs and budget. You won't be disappointed.

[Simon_LDT]

I think the 22k figure is the input impedance (going by the specs I see on the EWA site). What are your sources (solid state/tube)? Maybe try a passive?

[Ali Tait]

The Slagle is a passive.

[ff1d1l]

If you like the Slagle, why not build one? Trannies off the site, box off ebay and the unquantifiable musical ecstasy of listening through something you've built!

[Light Dependant Resistor]

I think the 22k figure is the input impedance (going by the specs I see on the EWA site). What are your sources (solid state/tube)? Maybe try a passive?

With passive attenuators, the figure of merit is what is called true impedance,
usually occurring close to half volume which is where the resistance from the
source greets the resistance to ground. Where they intersect and the resulting
resistance is the same, is the passives true impedance.

This describes the most common form of Pad circuit which is a L pad
namely a series resistance connects the source to the output, and a
shunt resistance connects the output to ground,

As with anything there are variations, and the terms linear and log
can provide - in the case of log a steeper entry curve ie volume not
commencing straight away. If it is your preference for volume to
commence as near as practicable to off, then a linear response
may be preferable to log.

To save much forum research, 15k is generally agreed to be the
preferred true impedance. ( DIY audio forum ). But 18k to 20k is also
very good as well. Anything lower like 10k will start to change
the dynamics of audio, and may appear a bit too dynamic suiting
some music but not others. Hence slightly higher usually is preferable.

While I am here, a common curly question is what is a passives output impedance ?
The output impedance at best, is its true impedance, however if volume is
placed at maximum then it will achieve connection from the source to the
output with effectively no loss. Output impedance applying to passives
is a misnomer, as they are not an active device.




Hope this assists

[RothwellAudio]

With passive attenuators, the figure of merit is what is called true impedance, usually occurring close to half volume which is where the resistance from the source greets the resistance to ground. Where they intersect and the resulting resistance is the same, is the passives true impedance.
This is so far off standard electronic theory, accepted wisdom, and common usage that I urge anyone reading it to take it with very large pinch of salt.

[Light Dependant Resistor]

This is so far off standard electronic theory, accepted wisdom, and common usage that I urge anyone reading it to take it with very large pinch of salt.

Its easy, just find a multimeter and measure without any signal leads connected, from input to output
then output to ground, where the resistances greet each other - the resistance measurement then shown
is the passive devices, true impedance. Each channel Left and Right should ideally be the same.

Where you may be confused is then attaching signal leads, but a passives true impedance is quite simple
reflective of its L pad resistances intersecting, It is after all a resistive divider, in this case variable.
Noting variations occur where they intersect with log or linear types, but at some point they indeed intersect.

[RothwellAudio]

Its easy, just find a multimeter and measure without any signal leads connected, from input to output
then output to ground, where the resistances greet each other - the resistance measurement then shown
is the passive devices true impedance.

Where you may be confused is then attaching signal leads, but a passives true impedance is quite simple
reflective of its L pad resistances intersecting,

Nothing about what you said confuses me at all, but the terms you use will definitely mislead others.
Figure of merit? Is a 20k pot twice as good as a 10k pot?

[Arkless Electronics]

This is so far off standard electronic theory, accepted wisdom, and common usage that I urge anyone reading it to take it with very large pinch of salt.

Ha! Just went to next page to shoot the bollocks down in flames but you got there before me!

deleted... dont attack the man jez please

[CageyH]

Hi,

I am on the lookout for a Pre Amp to go with my EWA M-50 Power Amp. I am currently using Ali's Slagle Passive Pre which is superb, and I can keep as long as I like with the probability of purchase, but I'm wondering if there is anything out there that isn't too expensive ( under £1000 S/H ) that would compete with it, or possibly better it ( not easy I bet ).

Would need to include a minimum of 3 inputs, Headphone out and remote control ( no line of site )

The Croft Epoch I had a short time ago was nice, but the gain was all wrong, I think the M-50 needs 22k rather than 47k, is that right?

Jerry's Bel Canto Pre3 looks good but it has green led screen, but I'm not keen on green lol.

I wonder if it would easier to connect a headphone amp to the Slagle output? Then forget about the remote?

Your thoughts, recommendations much appreciated.

Mike.

A Q20P at £960 new, as it fits in your given budget.

[Arkless Electronics]

Ha! Just went to next page to shoot the bollocks down in flames but you got there before me!

deleted... dont attack the man jez please

So it's fine to repeatedly and regularly mislead AOS members with blatantly incorrect falsehoods shrouded in a bit of technical sounding gobbledygook to make it sound plausible is it? "False news" (to make it topical) welcome but calling it out and ridiculing it not? If it were up to me I'd do something about a trade member repeatedly proffering false information and advice which is very definitely WRONG... or does he have to advise sticking a finger in a mains socket before anything happens?

[struth]

you know rules jez. similar to football.. play the ball

[Barry]

This is so far off standard electronic theory, accepted wisdom, and common usage that I urge anyone reading it to take it with very large pinch of salt.

It reads as though it is written in 'Chinglish'. No salt needed, just an understanding that the term 'impedance' is simply that of the variable potentiometer used.

[Light Dependant Resistor]

It reads as though it is written in 'Chinglish'. No salt needed, just an understanding that the term 'impedance' is simply that of the variable potentiometer used.

And resistance is ? ...Answer - the real part of impedance exhibiting no phase shift between the voltage and current.

[mikeyb]

Thanks for all the info, I only asked to see if there was anything better that could give me headphone out and remote, but having thought about it and seen that the Slagle has 2 outputs it would seem the best option for my needs would be too add a headphone amp to the spare output on the Slagle and forego the remote.

The EWA Q20-P would no doubt be ideal but I don't buy new nowadays and would rather look for value in used items, not that I think that the Q20 is poor value, it's very good, I've not heard it at home yet.

I'll have a hunt around for a headphone amp to try out and see if that's the way to go.

[Arkless Electronics]

I see he's edited it to remove some of the most glaring errors but there is no such thing as "true impedance" and no "figure of merit" applicable to a passive and nor is there any way that specific values will affect the dynamic range... not without a compander hidden in the potentiometer!
The worst (highest) output impedance is at the electrical midpoint of the pot (assuming a low source resistance), not the opposite as LDR's post originally hinted.
To be pedantic, we are talking resistance not impedance when discussing a passive pot (and in this context specifically a passive pot), A few MHz would be the lowest frequency where impedance would be more suitable a term.

[Edward]

<snip>

Your thoughts, recommendations much appreciated.

Mike.

I had a similar question recently and got lots of useful feedback here (http://theartofsound.net/forum/showthread.php?50963-Recommend-me-a-preamp-please).

Ended up with a Radford Revival preamp - well pleased.

Edward

[mikeyb]

I had a similar question recently and got lots of useful feedback here (http://theartofsound.net/forum/showthread.php?50963-Recommend-me-a-preamp-please).

Ended up with a Radford Revival preamp - well pleased.

Edward

thanks for the link, I've now decided that the best way to go would be to add a Headphone amp via RCA in from the Slagle Pre and forego the remote ( unless the HA came with one ), so I am now browsing various reviews for a decent Headphone amp that goes well with the rest of my system.

Irony is I've owned a couple in the past and sold them on when I wasn't needing them lol

[struth]

plenty good headphone amps for not much money these days mike. ive 2 chinese ones and both are great

[Light Dependant Resistor]

I see he's edited it to remove some of the most glaring errors but there is no such thing as "true impedance" and no "figure of merit" applicable to a passive and nor is there any way that specific values will affect the dynamic range... not without a compander hidden in the potentiometer!
The worst (highest) output impedance is at the electrical midpoint of the pot (assuming a low source resistance), not the opposite as LDR's post originally hinted.
To be pedantic, we are talking resistance not impedance when discussing a passive pot (and in this context specifically a passive pot), A few MHz would be the lowest frequency where impedance would be more suitable a term.

I have not edited anything.

[wee tee cee]

Mike why dont you get Colin to hot rod your TQ CLAYMORE. Head phone /DAC/Phono section are all excellent plus youve already got a remote. Ive had a few HPAs and Dacs the Tq Claymore is by far and away the best ive tried.

Failing that the q20 pre would be a perfect match and within budget-bet the headphone section would be stellar!!!

[Light Dependant Resistor]

So it's fine to repeatedly and regularly mislead AOS members with blatantly incorrect falsehoods shrouded in a bit of technical sounding gobbledygook to make it sound plausible is it? "False news" (to make it topical) welcome but calling it out and ridiculing it not? If it were up to me I'd do something about a trade member repeatedly proffering false information and advice which is very definitely WRONG... or does he have to advise sticking a finger in a mains socket before anything happens?

:peace: No. just saving forum members lives when it actually matters : http://theartofsound.net/forum/showthread.php?51225-Mains-conditioner-home-made-as-good-as-Isotek-Aquarius/page5&highlight=oscilloscope

[mikeyb]

I've managed to sort of fix this issue by digging out the NuForce iOS DAC/Headphone amp that I was selling. It's not ideal as I can only run my iPad through it as it's an iOS only input on it, but it will do the job for just now and once I get my Vivant Phono stage back from loan I'll get the Slagle hooked up again and that should be my output side sorted for a little while 😊

The NuForce DAC is pretty decent, pretty close to my Pi/Boss Dac setup with the added bonus of Headphone out.

[RothwellAudio]

:peace: No. just saving forum members lives when it actually matters : http://theartofsound.net/forum/showthread.php?51225-Mains-conditioner-home-made-as-good-as-Isotek-Aquarius/page5&highlight=oscilloscope

True, you were advocating safety, but your assertion that the mains cannot be measured directly with an oscilloscope was plain wrong.

[Light Dependant Resistor]

But it remains that it is not safe to do so. The emphasis is surely for AOS members, should be to start with safe methods, not to create
enthusiasm for what is potentially a lethal form of measurement.

http://www.diyaudio.com/forums/equipment-tools/128868-basic-oscilloscope-usage-questions.html

[RothwellAudio]

Crossing the road is potentially lethal - you just need to be careful.
BTW, what's the link to another forum for?

[Light Dependant Resistor]

Crossing the road is potentially lethal - you just need to be careful.
BTW, what's the link to another forum for?

Hi Andrew
To show others have similarly raised safety issue questions: http://www.diyaudio.com/forums/equipment-tools/128868-basic-oscilloscope-usage-questions.html
Post 6
"Unfortunately, the standard in emasuring devices, including generators, scopes etc, is that the ground is conencted directly to earth potential, which is basically near to mains voltage 0. This means that wherever you hook up your probe ground, you short that poit to earth potential - and if it's not already there or fully floating, this can be a disaster. "

Post 9
"Most lab scopes' earthing lug is internally connected to the probe's shield, so regardless if you use a isolation transformer or not, you still have the issue that the probe common is earthed. You have the option, with said iso-xfmr, of "floating" the scope (by not connecting the earthing lug or third prong to ground), but this is most certainly a safety hazard, as the case of the scope can become energized."

[337alant]

I really like my Avondale Audio 821A pre amp
I bought a pair of 821A pre Amp boards form Les Wolstenholm from Avondale Audio. I added a Elma 5 way switch, a Goldpoint stepped attenuator and a power supply with TPR4 regs
it has 5 X gain which is ample for may sources and it sounds superb IM

http://avondaleaudio.com/store/#!/Audio-Modules/c/9897165/offset=0&sort=normal

Alan

[alphaGT]

If you like the Slagle, why not build one? Trannies off the site, box off ebay and the unquantifiable musical ecstasy of listening through something you've built!

What are the merits of a preamp built by Trannies? :)


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[alphaGT]

I too am shopping for a preamp, and I've got to say it is the most difficult component to buy. I guess if price were no object, it would be much easier! But, trying to narrow down the field can be a daunting task, so many variables.


Sent from my iPad using Tapatalk

[Macca]

What are the merits of a preamp built by Trannies? :)


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Lipstick marks on the capacitors?

[alphaGT]

Lipstick marks on the capacitors?

Ha! Yes of course! A very exciting preamp....


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[anthonyTD]

Chris,
With all due respect, those of us who contributed to that thread, were in no way recomending this method to forum members, and were merely pointing out that it can be done, and is done by person's here who have an electronic background.
Hi Andrew
To show others have similarly raised safety issue questions: http://www.diyaudio.com/forums/equipment-tools/128868-basic-oscilloscope-usage-questions.html
Post 6
"Unfortunately, the standard in emasuring devices, including generators, scopes etc, is that the ground is conencted directly to earth potential, which is basically near to mains voltage 0. This means that wherever you hook up your probe ground, you short that poit to earth potential - and if it's not already there or fully floating, this can be a disaster. "

Post 9
"Most lab scopes' earthing lug is internally connected to the probe's shield, so regardless if you use a isolation transformer or not, you still have the issue that the probe common is earthed. You have the option, with said iso-xfmr, of "floating" the scope (by not connecting the earthing lug or third prong to ground), but this is most certainly a safety hazard, as the case of the scope can become energized."

[Gazjam]

To the OP:

Look into a second hand preamp by Densen, these crazy Scandanavians pride themselves in their kit having 'Air Guitar factor', and owning one myself I wouldn't disagree.

Boogies like a b*stard and gets right to the heart of the Tune.
Strongly recommended.

[Cycleallday]

Chris,
With all due respect, those of us who contributed to that thread, were in no way recomending this method to forum members, and were merely pointing out that it can be done, and is done by person's here who have an electronic background.

Would it be possible for forum members to restrict posts to the subject raised by the post originator and move any unrelated discussions to an appropriate subject post elsewhere.

Maybe its time for a moderator to step in to bring a common focus to this discussion.

Thank you

Mel

[walpurgis]

Thread drift is not generally moderated. Feel free to post on the original topic to steer the thread back in the direction of choice.

[struth]

Hopefully it will get back on track if there is any more interest in the subject