[goorackerelite]

I'm wondering what the SQ difference between these would be? I know the Little Dot series are all printed circuit boards, where as the Woos and the Darkvoice amps appear to be point to point wired.

I am a guitar player and I do have a point to point tube amp that has a warmth and roundness that my circuit board tube amps do not. I'm wondering if point to point tubed headphone amps carry the same sentiments.

Best

 

[grawk]

It's more likely the circuit design for the amp that makes it "warm and round" than the point to point wiring.

Point to point lets you have the shortest possible signal path, with the tradeoff being increased chance of crosstalk and potentially lower reliability.

 

[atbglenn]

I'd much rather have point to point from a service standpoint. If a resistor burns on a printed circuit board, it will usually burn the board. If there is a short, traces on the board will usually disintegrate. Although it can be repaired, I'd rather deal with point to point since it is much easier to repair without any evidence that a repair was actually done. I'm just very picky about those sort of things. I don't think it makes much of a difference in sound quality though. It all depends on the design of the circuit.

 

[FallenAngel]

Yeah, but try building a discrete solid state amp P-to-P, you'll go nuts.

 

[atbglenn]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Yeah, but try building a discrete solid state amp P-to-P, you'll go nuts.

You're right about that. I was talking about tube circuits

 

[nikongod]

Quote:

Originally Posted by FallenAngel /img/forum/go_quote.gif Yeah, but try building a discrete solid state amp P-to-P, you'll go nuts.

Discrete opamp, I agree, Discrete SS amplifier or buffer not so clear-cut.

 

[grawk]

The flip side is you're somewhat more likely to NEED to repair a point to point design.

 

[Uncle Erik]

Quote:

Originally Posted by grawk /img/forum/go_quote.gif The flip side is you're somewhat more likely to NEED to repair a point to point design.

I politely disagree.

What is it about a PCB that makes it more reliable? Paper thin traces are not nearly as sturdy as an actual, insulated wire.

Before I got into hi-fi, I restored old radios. Still do, but spend more time building more gear these days. Having been through over 100 sets, I have yet to have seen a failure due to point-to-point wiring. Most sets went down from bad filters, but never because the tie points or wire failed.

I have, however, seen numerous scorched PCBs that became unusable (or would need to be jumpered into a point-to-point setup, anyway), cracked PCBs and traces lifted by excess heat. From what I've seen, PCBs are less reliable, more prone to failure and a major pain to repair. If a component fails in a point-to-point setup, it can be replaced in a few minutes, as good as new. That's why gear was built point-to-point in the days before planned obsolescence.

Point-to-point can work for decades, as well. My oldest set is an Atwater-Kent neutrodyne, circa 1934. I went through it and left much of the 70+ year old wire in place. Had similar luck with a 1946 Hammarlund. The wire and tie points are fine.

Noise, etc. can be eliminated depending on the design, no different from a PCB.

Also, you can have a superior ground plane in point-to-point.

Anyhow, having been through so many old point-to-point sets, that's how I build my projects. I plan to keep them for the long term and pass them along to family. I'd hate for something I built to be thrown out because a resistor cooked off and delaminated the PCB. I'd much rather have the gear kept in service because replacing the bad resistor took ten minutes and cost $25.

 

[john_jcb]

Quote:

Originally Posted by atbglenn /img/forum/go_quote.gif I'd much rather have point to point from a service standpoint. If a resistor burns on a printed circuit board, it will usually burn the board. If there is a short, traces on the board will usually disintegrate. Although it can be repaired, I'd rather deal with point to point since it is much easier to repair without any evidence that a repair was actually done. I'm just very picky about those sort of things. I don't think it makes much of a difference in sound quality though. It all depends on the design of the circuit.

Repair of a well done point to point amp is not difficult if the wiring and parts placement is well thought out. if you have a rats nest of parts and wires going everywhere it may be extremely difficult to remove the failed component. In some cases I have seen amps where certain failures would almost necessitate rebuilding the entire amp.

 

[atbglenn]

Quote:

Originally Posted by john_jcb /img/forum/go_quote.gif Repair of a well done point to point amp is not difficult if the wiring and parts placement is well thought out. if you have a rats nest of parts and wires going everywhere it may be extremely difficult to remove the failed component. In some cases I have seen amps where certain failures would almost necessitate rebuilding the entire amp.

You are right about that. That is why I never buy anything wired like a rats nest.

 

[Uncle Erik]

Quote:

Originally Posted by john_jcb /img/forum/go_quote.gif Repair of a well done point to point amp is not difficult if the wiring and parts placement is well thought out. if you have a rats nest of parts and wires going everywhere it may be extremely difficult to remove the failed component. In some cases I have seen amps where certain failures would almost necessitate rebuilding the entire amp.

They're not that hard to work on, even with lots of components and wires. The worst I worked on was an old Hallicrafters that had a couple of caps stuck in a corner and partially blocked by a gang of tuning capacitors. It took a little forethought and about 45 minutes to get them out and the new ones in. Old surgical tools are helpful - you only need to clear a path of about an inch or so to work. Not that difficult, either. Once you've been through a few that don't smoke when you turn them on or just don't turn on (I've seen that more than once

) your confidence goes up and you'll tackle the challenging stuff.

 

[Thermionic]

I have often wondered about this myself and rather incline towards point to point philosophy for SQ reasons in relatively simple audio circuits, and this includes both solid state and tube circuitry. I think by wiring components directly (or as nearly as possible) to each other one removes at least one solder joint and some track, and perhaps reduces some stray capacitance as well. On the other hand things are never simple and classical point to point if done ‘correctly’ and in the old way often involved the use of tag strips and some extra wiring as well, and did not have the shortest signal paths (think Leak Stereo 20 say). I think it is fair to say though that the PCB is has proved to be a cheap and simple way of ‘gluing’ electronic components together in the production environment, and hard wiring is expensive, usually (though not always) confined to prototyping and projects where the use of a PCB is not economic. Of course there is point to point and point to point and I am here reminded of the works of art usually to be found in old Amateur Radio Handbooks that use wonderfully neatly done structures of un-insulated tinned copper wire, as opposed to just insulated hook up wire as found in much modern hand wired valve equipment.

Years ago when I tried to built the best preamplifier I could, I point to point wired mostly everything using a mixture of solid copper and silver wire. I used to work as a wireman for an medical electronics company so was pretty deft with the soldering iron. The inputs were simply straight lengths of about 16 gauge bare copper taken directly from the phono sockets to the terminals of the selector switches. The rest was knife and forked with a mixture of silver (strips - large surface area) and matrix board with the components all on top of each other sometimes looking a bit like a miniature Stonehenge. A great friend of mine was working with microwaves at the time and much of his circuits used chip components in this fashion, so I thought why not for audio. It was a nightmare to fault find and unfortunately I had nothing much to compare my electronic sculpture with, so I never knew if it was really any good at all, and in time went on to use something else. Though I do wonder if the increasing use of surface mount components these days for reasons of economy might also not be such a bad thing for SQ as well, by keeping signal conductors short and doing away with leaded components.

I have also found that there are different ways of ‘doing’ PCBs as well, in that the high end firm Audio Research seems to place a lot of its components directly (or at least solder's them) onto the top of un-lacquered pcb tracks in a rather point to point way very closely around their valve holders. Indeed on my LS7 it seems that the signal components are all wired in this way (I might be wrong here though). They also keep signal paths to the input selector very short, as of course do many other makers.

Perhaps someone should make an amp in two versions; one pcb and one point to point wired and see what if any are the sonic differences. Perhaps it’s already been done, and I know that I have have waffled enough.

 

[Spareribs]

This is a very interesting topic. I plan on getting a Marshall guitar tube amp and the Marshall 1974X model is a reissue from the 60's. Marshall stresses that it is hand wired (point to point) as part of thier sales pitch. It is a highly regarded amp though.

 

[928GTS]

Quote:

Originally Posted by Spareribs /img/forum/go_quote.gif This is a very interesting topic. I plan on getting a Marshall guitar tube amp and the Marshall 1974X model is a reissue from the 60's. Marshall stresses that it is hand wired (point to point) as part of thier sales pitch. It is a highly regarded amp though.

As an aside you're probably better off buying a Ceriatone copy of a 1974X. The Marshall reissue takes quite a bit of expenditure just to try and get it sound somewhere close to an original.

 

[sbradley02]

I am looking at possibly doing my first point to point tube amp.
 
Starting from the schematic, are there any recommended guides for laying out the chassis?
 
Thanks