Passive pre recommendations & advice on pots, etc

[Simon_LDT]

So I've been running a Tisbury passive (mk2) for a few weeks now and I really like it. Straight away I heard no compromise in sound, dynamics still there and no roll-off or lack of bass I could hear. I swapped back in my Arcam C31 active the other day and to my surprise it held it's own really well. To be honest I don't think I could hear a clear difference between them. I did swap back and forth a few times and both gave what I heard to be identical sound quality (any differences I thought I could hear I think was just my mind trying to convince me of something not there possibly). Maybe my system isn't revealing enough, I don't know.

I'm thinking although after this I should probably stick to the active pre, I like the idea of using a passive (1 less plug, more direct path, can route the AV system through it without needing to power up another amp). Needs to have 2 sets of outputs (for power amps and headphone amp) and at least 3 inputs.

I've been doing a bit of research into passives and I'm not sure how to proceed if I want to upgrade. For example, I would ideally like a remote option (which I can power using my HDplex LPS) but I've read that it's better to go without that as the extra electronics can potentially compromise the sound. Same with what pot to use, some say stepped is best but then what type (shunt, ladder)? What about p2p wiring vs pcb?

What about pot impedance? The Tisbury is supposedly 10kohm which into my 22kohm amps seems to work a treat so ideally want something similar. Also, not sure it's a good idea to have a type of pot which varies resistance as the dial is turned. From what I've read something like a stepped ladder type keeps the resistance the same throughout.

Budget, probably around £500 but may be willing to go higher for something worth it

Some I've considered/looked at:

Schiit Saga - looks good, has remote, but don't like the idea that the tube buffer is always active/on, even when only in pure passive mode
Khozmo - looks good, has remote, don't like the look of the switch/pot knobs and apparently they're not well regarded (Lorlin?)
Hattor - same as above
NVA P50 - Not sure I like the acrylic look, no remote but apparently for SQ reasons
Rotel Michi (seen in classifieds from Josie) - Looks good but no remote and seems to be all pcb - not sure what pot it uses
Icon Audio - ticks many boxes but not sure what pot it uses.

Maybe I'm being too fussy haha. Absolute main priority is SQ but I would want a decent looking case and nice knobs, etc, even if it costs a little more for it.

[farflungstar]

Depending on your budget I recommend The Truth - it takes the last veil that all pots, relays etc have out of the equation.

[walpurgis]

Depending on your budget I recommend The Truth - it takes the last veil that all pots, relays etc have out of the equation.

There have been numerous discussions here about LDR devices. Some in favour, some not. I like the idea!

[farflungstar]

The Truth doesn't operate as an LDR (but I'm not technical and not getting into that) The OP asked for suggestions and I offered one. There has also been numerous discussions about conventional pots.

[Simon_LDT]

The Truth sounds interesting from what I've just looked up.

[RothwellAudio]

Depending on your budget I recommend The Truth - it takes the last veil that all pots, relays etc have out of the equation.

The OP is looking for a passive pre-amp. The Truth is an active pre-amp.

[farflungstar]

There have been numerous discussions here about LDR devices. Some in favour, some not. I like the idea!
I thing may have misread you!

For the OP. I also started out with the Tisbury. It's ok.
I then went the top of the line Alps 500quid job. I then went to Dave slaglesb autoformers after listening to S&B. Each time there was greater clarity. The Slagles are absolutely superb. I then took a punt on the Truth - endgame. It has it's faults but it beats all else in my opinion in my system.

The Slagles are relatively cheap - it depends on your budget.

[RothwellAudio]

It sounds to me that the Tisbury has everything you want except remote control. Apart from remote control, what are you looking for in the "upgrade"? It's perfectly possible to make passives much more expensive than the Tisbury but I'm not convinced there's much advantage to it. Point-to-point wiring for example can be simply a labour-intensive (and therefore expensive) waste of time imho.

[farflungstar]

The OP is looking for a passive pre-amp. The Truth is an active pre-amp.
Yes it plugs into the wall - but it adds no gain - the buffers require power but the signal isn't boosted in any way.

[Macca]

Most of them are available mail order so you can try and send back if you don't rate them. The NVA have 3 sets of outputs which is always handy.

[farflungstar]

It sounds to me that the Tisbury has everything you want except remote control. Apart from remote control, what are you looking for in the "upgrade"? It's perfectly possible to make passives much more expensive than the Tisbury but I'm not convinced there's much advantage to it. Point-to-point wiring for example can be simply a labour-intensive (and therefore expensive) waste of time imho.
You're right Dave - it depends what the OP wants. Better sound? Convenience?

[farflungstar]

According to the original post priority is SQ - in which case I'd suggest Slagle or Truth. But that's only my opinion.

[Macca]

I found quite a significant difference between the Tisbury and other, more expensive passives.

[farflungstar]

+1

[Arkless Electronics]

It's not a good idea to have more than one output with a passive.

[Macca]

It's not a good idea to have more than one output with a passive.

go on...

[RothwellAudio]

Yes it plugs into the wall - but it adds no gain - the buffers require power but the signal isn't boosted in any way.
Having unity gain doesn't make it passive - that isn't what passive means.

[RothwellAudio]

go on...

If you have two outputs feeding two devices the two input impedances will be in parallel and the combination may well be on the low side.

[Arkless Electronics]

go on...

I knew you would ask.... :D The worst case generally CAN be when one item is switched off. If you have a passive pre (this applies to all pres really but passives will be vastly more effected, some valve gear second worse here) driving both your power amp and a headphone amp (or anything else) then the two amps being driven "see" each others inputs. Sometimes when gear is switched off its input impedance can be highly non linear and can cause distortion which you hear via the amp that is switched on. An AOS member had just such an issue a couple of weeks ago I recall. Even much less serious scenarios are highly likely to degrade SQ. Things connected to "Tape out" can have a similar effect BTW.

Without analysing specific makes and models of kit and having access to their circuit diagrams etc it's impossible to say precisely what kit will be adversely effected etc.

To climb on to my soapbox, it's one of the MANY things in audio that are important but virtually ignored by/not known to audiophiles... whilst meanwhile they obsess about stuff so unimportant it probably makes no difference....

[Simon_LDT]

It sounds to me that the Tisbury has everything you want except remote control. Apart from remote control, what are you looking for in the "upgrade"? It's perfectly possible to make passives much more expensive than the Tisbury but I'm not convinced there's much advantage to it. Point-to-point wiring for example can be simply a labour-intensive (and therefore expensive) waste of time imho.

I like the Tisbury but I ideally need more control of volume (more steps) because while I can generally find a good volume without problem at normal/louder levels it can be difficult at lower volumes to get what I need (due to thin walls and neighbours). One setting is too low but then the next has a bigger volume jump than I'd like.

Also I've read that while the Tisbury is great and super good value for money, I see many comment that it's easily beatable for not too much more money.



I knew you would ask.... :D The worst case generally CAN be when one item is switched off. If you have a passive pre (this applies to all pres really but passives will be vastly more effected, some valve gear second worse here) driving both your power amp and a headphone amp (or anything else) then the two amps being driven "see" each others inputs. Sometimes when gear is switched off its input impedance can be highly non linear and can cause distortion which you hear via the amp that is switched on. An AOS member had just such an issue a couple of weeks ago I recall. Even much less serious scenarios are highly likely to degrade SQ. Things connected to "Tape out" can have a similar effect BTW.

Without analysing specific makes and models of kit and having access to their circuit diagrams etc it's impossible to say precisely what kit will be adversely effected etc.

To climb on to my soapbox, it's one of the MANY things in audio that are important but virtually ignored by/not known to audiophiles... whilst meanwhile they obsess about stuff so unimportant it probably makes no difference....

That was me also. Seems this could be trickier to sort out than I initially thought... I really don't want to be plugging the headphone amp in/out all the time. Even if I had 2 passives, 1 for amp and 1 for headphone amp I'd still have the problem of connecting up both outputs on my DAC into the passives and having the distortion problem I had in the other thread. So even using a tape out no good either...?

[JohnJo]

I had a Tisbury passive but preferred the Alps Blue pot in my Icon Audio passive. For me the Alps conveyed the boogie factor a lot better. A more musical presentation all round I thought. Suppose it depends on the type of presentation you prefer.

[farflungstar]

I think marco had a very good Glasshouse passive for sale at a ridiculously low price then withdrew it. Ask him.

[Macca]

I knew you would ask.... :D The worst case generally CAN be when one item is switched off. If you have a passive pre (this applies to all pres really but passives will be vastly more effected, some valve gear second worse here) driving both your power amp and a headphone amp (or anything else) then the two amps being driven "see" each others inputs. Sometimes when gear is switched off its input impedance can be highly non linear and can cause distortion which you hear via the amp that is switched on. An AOS member had just such an issue a couple of weeks ago I recall. Even much less serious scenarios are highly likely to degrade SQ. Things connected to "Tape out" can have a similar effect BTW.

Without analysing specific makes and models of kit and having access to their circuit diagrams etc it's impossible to say precisely what kit will be adversely effected etc.

To climb on to my soapbox, it's one of the MANY things in audio that are important but virtually ignored by/not known to audiophiles... whilst meanwhile they obsess about stuff so unimportant it probably makes no difference....

Thanks Jez. I sometimes connect an active sub to my passive but can't say I've noticed any issues. The multiple outputs are intended for bi and tri amping.

[Arkless Electronics]

Thanks Jez. I sometimes connect an active sub to my passive but can't say I've noticed any issues. The multiple outputs are intended for bi and tri amping.

It doesn't matter what it's "intended for"... the elektrickery doesn't know that...

Often one will get away with it no problem, as I explained earlier it would take analysis of individual circumstances and equipment to say what to expect. It will probably always have more effect than anything to do with cables though!

[Arkless Electronics]

I like the Tisbury but I ideally need more control of volume (more steps) because while I can generally find a good volume without problem at normal/louder levels it can be difficult at lower volumes to get what I need (due to thin walls and neighbours). One setting is too low but then the next has a bigger volume jump than I'd like.

Also I've read that while the Tisbury is great and super good value for money, I see many comment that it's easily beatable for not too much more money.




That was me also. Seems this could be trickier to sort out than I initially thought... I really don't want to be plugging the headphone amp in/out all the time. Even if I had 2 passives, 1 for amp and 1 for headphone amp I'd still have the problem of connecting up both outputs on my DAC into the passives and having the distortion problem I had in the other thread. So even using a tape out no good either...?

Probably not. Depends on whether it's buffered or not. Most aren't. What you need is a double pole changeover switch on your passive pre to switch one set of output sockets on at a time... but not both!

[Marco]

I think marco had a very good Glasshouse passive for sale at a ridiculously low price then withdrew it. Ask him.

Not me, Adrian. It's another guy. I had a Goldpoint for sale, but it's now gone.

Marco.

[farflungstar]

Ok marco - sorry - dementia!

[Macca]

It doesn't matter what it's "intended for"... the elektrickery doesn't know that...


Sure, I understand that.

[Bigman80]

I knew you would ask.... :D The worst case generally CAN be when one item is switched off. If you have a passive pre (this applies to all pres really but passives will be vastly more effected, some valve gear second worse here) driving both your power amp and a headphone amp (or anything else) then the two amps being driven "see" each others inputs. Sometimes when gear is switched off its input impedance can be highly non linear and can cause distortion which you hear via the amp that is switched on. An AOS member had just such an issue a couple of weeks ago I recall. Even much less serious scenarios are highly likely to degrade SQ. Things connected to "Tape out" can have a similar effect BTW.

Without analysing specific makes and models of kit and having access to their circuit diagrams etc it's impossible to say precisely what kit will be adversely effected etc.

To climb on to my soapbox, it's one of the MANY things in audio that are important but virtually ignored by/not known to audiophiles... whilst meanwhile they obsess about stuff so unimportant it probably makes no difference....
This is very interesting Jez, ive got two outputs on my Pre, one into my amps and one into my headphone amp. I cant hear a difference when im only using one of the outputs. I'll try it with both tomorrow. Very interesting!

Sent from my EVA-L09 using Tapatalk

[Simon_LDT]

Probably not. Depends on whether it's buffered or not. Most aren't. What you need is a double pole changeover switch on your passive pre to switch one set of output sockets on at a time... but not both!

Never heard of that before but I guess it's not something common?

[Arkless Electronics]

Never heard of that before but I guess it's not something common?

It's commonly available yes. L & R out from passive to centre contacts and then just take one set of L & R outs from say the left side of the switch to one pair of phono sockets and repeat from the other side of the switch to other output sockets. You''l obviously have to drill a hole for the switch.

[DSJR]

I regularly use two power amps off my workroom passive preamp and I genuinely cannot hear the difference having one or both connected together. I appreciate the electrics may suggest otherwise, but I suggest it's at inaudible frequencies in practise. The Crowns offer 13k input impedance with the gain pots set around three quarters up.

I've used the dinky attenuators as used in the Tisbury and although in isolation they're ok and with superb channel matching obviously, I really do prefer a little plastic film pot I know rather well now. From around ten degrees from minimum on the control, channel matching is fine right round to maximum.

Valve amps are different, or at least older ones may be. This may be due to insensitivity on their inputs, or very high output impedance on the active preamps and this is where careful matching comes in I believe.


For me at any rate, I've been able to compare a modern source straight into a power amp and then insert a few preamps, match the volume as carefully as possible and see if the sound changes by their insertion. In *my* situation and with power amps offering input impedances of 12k to 25k +, a passive preamp has the least to zero effect sonically, even the shunt-attenuator version which really does play havoc with any theoretical 'impedance matching.' Maybe an Albarry amp with input of 1.5k may show an effect, but I'll never be able to find out now.