300B / 845 SET amplifier

[Opti-cal]

You still need to get (longer) interconnects from the pre amp to the power mono blocks. So is the premise here that speaker cables have more influence on both cost and sound quality?

If the longer runs of interconnects are balanced I would guess yes. Like all things hifi, it probably depends. The differences between cheap (relative) and expensive balanced interconnects are less easily discernible to me than differences between unbalanced interconnects and indeed speaker cable. Different types/materials will work better in some systems than others.

Back to the sub-plot somewhat, I think Barry has concluded that by using balanced interconnects for the long run of cable needed to physically reach the amplifiers, it makes more sense to have this (low level) signal balanced than having the same long run of 'signal' carried over the same distance at speaker level power. Maybe.

[Filterlab]

I'd agree. My system is fully balanced and changing the balanced cables has made less difference than changing the speaker cable. I've also found that a higher price doesn't necessarily mean higher quality with balanced cables. I've set upon Chord Clearways throughout. I've tried a few much more expensive and they were noticeably worse in my system.

It's a strange old game!

[Opti-cal]

Another aspect to consider is that a lot of tube power amps are not true balanced inputs. They may have balanced inputs but often they are just wired to accept XLR input for convenience. Making the circuit fully balanced is pretty complex as the components are inverted/non inverted I can't quite remember. I don't have much knowledge on the subject but a quick search did suggest:

The only confirmed manufacturers of new tube amps which are balanced are Mcintosh, Rogue Audio, Cary Audio, Atma-Sphere, ARC and VTL.

There's probably a few more but if you're getting a custom built it could certainly be factored in.

[Opti-cal]

I'd agree. My system is fully balanced and changing the balanced cables has made less difference than changing the speaker cable. I've also found that a higher price doesn't necessarily mean higher quality with balanced cables. I've set upon Chord Clearways throughout. I've tried a few much more expensive and they were noticeably worse in my system.

It's a strange old game!

Sorry for thread derailment (but as it's your thread!) I've just ordered a pair of these.

https://www.aliexpress.com/item/4000...22ac4c4ddS2eYv

They tick a lot of boxes for me. 6N OCC copper cable with copper XLR plugs. Should be the business for the price. I really like the Chord Clearway range too actually, decent value. There are a lot of chord haters but their mid range stuff always does a good job for me.

[Barry]

Back to the sub-plot somewhat, I think Barry has concluded that by using balanced interconnects for the long run of cable needed to physically reach the amplifiers, it makes more sense to have this (low level) signal balanced than having the same long run of 'signal' carried over the same distance at speaker level power. Maybe.

Yes, that is exactly my thinking. Before the current set up, I had to use two different length speaker leads, roughly 6m and 16m in length. These had a loop resistance of 0.104 Ohm and 0.202 Ohm respectively, meaning the damping factor into an 8 Ohm load was 77 and 40. The output impedance of the amp was only 0.02 Ohm. The loop resistance and inductance of any speaker cable, regardless of length, ideally ought to be no more than 0.1 Ohm + 3uH.

The general rule of thumb is for the loop restistance to be no more than 5% of the nominal speaker impedance, which if assumed to be 10 Ohm, is 0.5Ohm, giving a damping factor of no more than 20. However, depending on the variation of the speaker's impedance with frequency, a series 0.5 Ohm esistance can exacerbate the variation in frequency response by up to 1dB, which may be audible.


Audible differences between different balanced interconnects are far, far less than those between different unbalanced cables, for the simple reason there is no duplication of the shield (screen) to act as signal return and safety earth. That is one of the reasons why balanced lines are used in professional broadcast and recording studios. One further advantage IMO, is the avoidance of the awful RCA phono connector through the use of XLR connectors.

[Filterlab]

There are a lot of chord haters but their mid range stuff always does a good job for me.

Same here. I have Chameleons in my second system (unbalanced) and they're excellent bits of wire which are a bargain price.

Both those and the Clearways just seem to be completely even, favouring no particular frequency range. Well thought out wiry bits.

[Filterlab]

Audible differences between different balanced interconnects are far, far less than those between different unbalanced cables, for the simple reason there is no duplication of the shield (screen) to act as signal return and safety earth. That is one of the reasons why balanced lines are used in professional broadcast and recording studios. One further advantage IMO, is the avoidance of the awful RCA phono connector through the use of XLR connectors.

When I did pro audio everything was balanced. One could have a tangle of cables running all over the place, past power points and power amps, with nary a hum. Just so easy to get a good signal.

[dowser]

I have difficulty in seeing why monoblocks have an advantage. Sure, you separate left and right channels, but at a cost of two lots of casework etc. For the same money you could by a stereo amp with much higher quality components and perhaps even better sound than the monoblocks.

Just throwing it out there.

Simple for me - I wouldn’t be able to move it by myself if it was integrated, and it would be huge!