What were your best sounding portable record players?

[Edward Huggins]

I'm not sure if the Mayflower amplifier has any Boost (Baxendall-like) associated with the Treble control circuitry - as distinct from just a "Cut" function.

[Synchrodyne]

It looks as though the Mayflower treble control, which is of the passive type, provides cut only. The GP42 treble control is also passive, but allows a small amount of lift as well as a lot of cut. There is a net loss of about 4 dB through the tone control unit, which reasonably correlates with the maximum available treble lift of 3 dB. The GP42 bass control is in the amplifier main feedback loop, and provides lift only.

As a “quick and dirty” comparison that would be easy to set up, in a GP2 + AL42 combination, substitute a Mayflower (using its “gram” input) for the AL42, then play mono records (or stereo records with the cartridge left and right outputs bridged) with the GP42 turned right down. Hardly rigorous, but it could be indicative of non-trivial differences between the AL42 and Mayflower that in part might be attributable to their different speaker drive units, although there would almost certainly be other contributors.


Cheers,

[Hartley118]

Originally Posted by mhennessy

...............Certainly, I've messed about enough with the geometry of my old SME 3009 in the past to minimise the tracking distortion as best as I could, so I think I'm left with the other stuff now.

I guess it's impossible to say whether it comes about as a result of the inherent harmonic distortion of the vinyl medium, or as a result of mastering, or as a result of "protection" limiting built into the cutter driver amplifiers. Less likely the first, I agree.

I'm not sure why many folk seem to not be bothered by it, but it does raise questions about expectations (given the massive hype around vinyl in recent times). As is quite likely for the younger demographic, if one hasn't experienced decent audio prior to seeking out vinyl, then perhaps people come to believe that it is somehow "right". Yes, adding distortion for artistic reasons is often an essential part of recording process, and we as humans can like it.

What doesn't exactly help is the modern trend for excess treble. It sells...

................... This stuff is complicated, and naturally our perspective half a century on is very different. But measurements will at least provide some facts

I guess that the first step is to check whether you're getting a flat frequency response through from disc to amplifier speaker output terminals. Do you have access to a frequency response test disc? Many audio oddities can be explained by a non-flat frequency response and as we know there are many variables in the chain.

Martin

[mhennessy]

Originally Posted by Synchrodyne

It looks as though the Mayflower treble control, which is of the passive type, provides cut only. The GP42 treble control is also passive, but allows a small amount of lift as well as a lot of cut. There is a net loss of about 4 dB through the tone control unit, which reasonably correlates with the maximum available treble lift of 3 dB. The GP42 bass control is in the amplifier main feedback loop, and provides lift only.

Yes, assuming they FM de-emphasis has been correctly implemented (haven't ever checked that, but I could do now I've fixed my Radiometer SMG40), then yes, it's treble-cut only. Knowing that the 5 by 8" version of that Goodmans speaker in an RP18 Sovereign needs the treble turned up full (some 14dB IIRC) to sound reasonable, I was surprised that the much larger unit in the Mayflower extends out as far as it does with no "help" from the amplifier.

For the GP42, I saw the 100k||330pF network, but wasn't sure exactly how it would behave with the cartridge (remembering that elsewhere we were discussing loading approaches for ceramic cartridges - definitely something I know relatively little about). Checking the service manual, it says +3dB in the test spec section, but of course, that'll be fed from an oscillator, not the cartridge.

Interestingly, the same manual states that the GP42 speaker is actually a Goodmans, not a Celestion! This rang a distant bell, and I was able to find this post (scroll to post #8) where I give the part numbers from the manual: http://www.vintage-radio.net/forum/s...ad.php?t=82784 - I note that they are not exactly the same number. In post #10, Dave mentions the Celestion... So, as far as Hacker were concerned, the Celestion was presumably equivalent (or better) than the original Goodmans, but the original Goodmans might not have been exactly the same as the unit fitted to the Mayflower.

While searching, I also found this: http://www.vintage-radio.net/forum/s...ead.php?t=1353 - where a change to a Celestion unit in a Mayflower was reported in very positive terms.

I like the idea of the test with a Mayflower. You're right; there are many other variables, but it's a good start and doesn't need specialist equipment. I'd measure the "raw" loudspeakers because I have the means, but just assessing them by ear while feeding them both from a modern amplifier and switchbox would be significantly better than nothing.

I'm really regretting not picking up a GP42 (or AL42) before the prices rocketed!

[mhennessy]

Originally Posted by Hartley118

I guess that the first step is to check whether you're getting a flat frequency response through from disc to amplifier speaker output terminals. Do you have access to a frequency response test disc? Many audio oddities can be explained by a non-flat frequency response and as we know there are many variables in the chain.

No, I don't have a test disc, sadly. The few people at work that still have them will need them, so I don't think a loan would be possible, but I'll ask when I get the chance...

I'm totally confident in the electronics (as I built it all ). The MM pre is Douglas Self's design from 1996, which is about as close to the RIAA spec as it gets. The cartridge is an Ortofon 510. I was impressed with that one, BTW, as it did give a new lease of life to my collection (because of the stylus profile reaching the unworn part of the groove, as mentioned earlier). It's hardly an expensive cartridge, but spending more would be hard to justify, given the amount I play records. Thanks for various re-issues over the years, I've finally got copies of everything on other formats, so records really are only played occasionally for fun. As I said, they have no right to sound as good as they do, despite everything. And the kids still enjoy playing their singles from time to time...

Either way, I've never heard a vinyl setup that doesn't have the characteristic HF behaviour. My life outside of the day job brings me into contact with a lot of modern hi-fi, where a very large proportion of dems at shows, etc, use vinyl at the moment - sometimes on exotic gear that costs as much as a house The modern trend for excess HF in speakers that I mentioned earlier just serves to highlight it for me - not a comfortable experience.

All that said, some older classical recordings can sound very convincing if you don't mind the background noise and there isn't too much brass or percussion. Radio 3 do a good job of cleaning them up for broadcast from time to time. My collection is mostly rock/pop stuff from the '70s onwards.

I've got quite a few .WAV files (from my collection plus loads from work) that clearly demonstrate what I mean. Including many that show the effect of incorrect stylus choice and the appropriate and inappropriate use of tools like CEDAR, etc. Perhaps I should find a way to share these more widely...

[suebutcher]

I've noticed that there's a big difference in tone when you use the BBH Black Box with the lid up. Ditto the Kingsley RKR. Were the heavy lids of small record player in wood cabinets designed to act as a bass resonator? If so, how did this work?

[mally1956]

Setup it was always advises to play with lid down ,it improves the sound,I always do that on my Conquest

[Hartley118]

Originally Posted by suebutcher

I've noticed that there's a big difference in tone when you use the BBH Black Box with the lid up. Ditto the Kingsley RKR. Were the heavy lids of small record player in wood cabinets designed to act as a bass resonator? If so, how did this work?

A thin plywood lid will certainly have a diaphragm resonance which will contribute to the overall bass quality, rather like the more scientific approach of the passive bass radiator used in some speaker enclosures.

Then of course with the lid closed, the ventilation holes may act as ports to create a vented enclosure, though I doubt that any designer analyzed the Thiele-Small parameters!

I expect that the designers of better-sounding players used an instinctive subjective approach to optimize these factors.

Martin

[Edward Huggins]

Originally Posted by suebutcher

I've noticed that there's a big difference in tone when you use the BBH Black Box with the lid up. Ditto the Kingsley RKR. Were the heavy lids of small record player in wood cabinets designed to act as a bass resonator? If so, how did this work?

The lid does not act as a "resonator". When closed, it seals the cabinet into one intergral sound enclosure to effectively load the speaker/s witha degree of back pressure. This pressure is usually then "vented" through a small port at the rear of most portable record players. It's known as a Reflex (or Ported) design. If you look at the rear of most small record players you'll see a vent/small ports.

[mhennessy]

There's no doubt the thin lid (and base) will contribute to the output at some frequencies - for better or worse. Many were just 3mm hardboard. Presumably a GP42 would be rather more substantial, but even the damped 12mm plywood panels were designed to flex at bass frequencies in BBC designs, for very good reasons.

The answer to Sue's question is mostly this:

The sound coming out of the rear of the drive unit is out of phase compared to what emerges from the front. So when the cone move forward to pressurise the air in the room, the partial vacuum created behind the cone simply sucks all that air back, reducing the net change in the room (which is what we hear, unless we are very, very close to the drive unit).

(Obviously, we're talking about ridiculously small variations in pressure here, but then the human hearing system is incredibly sensitive)

Mounting a bare drive unit on a baffle (i.e. a sheet of timber) will reduce this effect. In fact, the overall dimensions of the baffle will determine the low frequency response (think about the wavelength of sound - perhaps 11 foot for 100Hz). That baffle doesn't have be a flat sheet - a box with an open back (such as a valve radio) will have much the same effect. As you go down in frequency, the wavelength increases such that you get cancellation. So the bigger the baffle, the better...

The ultimate outcome is the sealed box - sometime called "infinite baffle" - where there's no chance of the sound coming from the rear of the diaphragm ever reaching the sound from the front. If you come across one of those with a removable rear panel, try listening to the effect of removing the panel...

A record player with the lid closed approximates a sealed box. OK, the seal isn't perfect, but it still goes a long way to reduce the cancellation that takes place when the lid is open.

Some loudspeaker enclosures are ported. These are deliberate openings that are dimensioned such that the air within the openings resonate at a chosen frequency to augment the output from the front of the driver. These are complex to design, and it's highly unlikely that any such openings on a record player were designed to behave in that way. Most likely, they are there to allow the amplifier/motor to cool.

[Hartley118]

Originally Posted by mhennessy

...... I've never heard a vinyl setup that doesn't have the characteristic HF behaviour. My life outside of the day job brings me into contact with a lot of modern hi-fi, where a very large proportion of dems at shows, etc, use vinyl at the moment - sometimes on exotic gear that costs as much as a house The modern trend for excess HF in speakers that I mentioned earlier just serves to highlight it for me - not a comfortable experience.

All that said, some older classical recordings can sound very convincing if you don't mind the background noise and there isn't too much brass or percussion......

Mark, I think you're possibly hearing the inevitable few percent of high-frequency distortion that's inherent in the disc cutting and tracing process. Even at mid-frequencies, a disc system is doing well if it achieves better than 0.5% THD. The remarkable thing is that it all works as well as it does!

If in doubt about these limitations, just jangle a bunch of keys in front of a good studio mike, record it on analogue tape, cut a disc, replay it on a first class player, then listen to see how much it sounds like the original.

I think that we've just about remained on topic, but in I'm in serious danger of suggesting digital as a solution

Martin

[suebutcher]

Originally Posted by mhennessy

Some loudspeaker enclosures are ported. These are deliberate openings that are dimensioned such that the air within the openings resonate at a chosen frequency to augment the output from the front of the driver. These are complex to design, and it's highly unlikely that any such openings on a record player were designed to behave in that way. Most likely, they are there to allow the amplifier/motor to cool.

Here's the left speaker of the Kingsley RKR - it's a stereo player with the drivers shooting sideways like the BBH - and the cooling port is right next to the speaker. Same on the other side. When I first looked inside I thought "This can't possibly be any good for the sound". The bass should cancel out because of the negative pressure from the rear of the speaker. But with the lid down and the player sitting on a table, it's actually fairly good; a bass guitar can be heard clearly even if a bass drum is a bit obscure. I did try covering the ports as an experiment, but it didn't make a big difference.

[Hartley118]

It doesn't really matter much where the port is located because wavelengths are long at low frequencies (e.g around 10 feet at 100Hz). The clever bit about a ported cabinet is that there's a phase inversion at resonance so the output of the port reinforces that of the speaker unit.

Martin

[mhennessy]

Originally Posted by Hartley118

Mark, I think you're possibly hearing the inevitable few percent of high-frequency distortion that's inherent in the disc cutting and tracing process. Even at mid-frequencies, a disc system is doing well if it achieves better than 0.5% THD. The remarkable thing is that it all works as well as it does!

If in doubt about these limitations, just jangle a bunch of keys in front of a good studio mike, record it on analogue tape, cut a disc, replay it on a first class player, then listen to see how much it sounds like the original.

I think that we've just about remained on topic, but in I'm in serious danger of suggesting digital as a solution

Yes, the trouble is, there are very real physical limitations with vinyl. The amount of HF energy is one (limited by the cutting drive coils), and the amount of LF energy being another. So there are lots of things you might need to do to the mix tape from the recoding studio during mastering. Such as greatly reduce the stereo separation at LF if you want the groove to remain deep enough for the stylus to follow. Or use multiband compression to increase the subjective loudness while maintaining or reducing the peak levels to stay within the limits of the cutting lathe - and to increase the distance between the programme and the noise floor. Or use de-essing to control sibilance. All in all, good mastering engineers were in demand, and they certainly earnt their money

So it's no wonder that vinyl sounds different to other formats - it's mastered very differently, out of necessity. That's just a basic engineering fact - no reason why that should start a format debate.

Of course, back in the day, recording engineers mixed for vinyl, thereby reducing the amount of tweaking needed by the mastering engineer. E.g., by not panning bass away from the centre, that's one less thing needed to be done at mastering. By controlling the sibilance on the vocal track only, the mastering engineering shouldn't need to aggressively de-ess the whole mix (obviously, whatever the mastering engineer does, it affects all components of the mix). What's interesting now is that recording engineers are having to re-learn the art of "mixing for vinyl" - there's countless articles out there about this. All interesting stuff.

In theory, you shouldn't need to "master"* a final mix before committing it to some other, more modern (possibly digital ) format. But that's not how it works in reality - many "contemporary" recordings fall victim to the "Loudness Wars", as we all know. This video compares a terrible CD master to a reasonable vinyl master (shame about the content!): https://www.youtube.com/watch?v=TsMpHDc7sGE - this is nothing to do with the technicalities of the respective formats; this was a non-technical decision for whatever reaons.

* I put "master" in quotes because there rather more to mastering than just compression, etc. For anyone who is interested, I highly recommend Mastering Audio by Bob Katz: https://www.amazon.co.uk/Mastering-A.../dp/0240808371

Is it harmonic distortion? Given a pure 1kHz sine wave, it's easy to hear <0.5% of clipping or crossover (easy to dem - we do). It's surprising how much more distortion you need when it's 2nd order "nice" stuff because of the masking effect (in the presence of 1kHz, it's much easier to hear 3kHz than 2kHz). But on typical programme material, clipping has to be pretty gross before we notice it (we're more sensitive to crossover distortion). This is a really good demonstration from an Audio Precision engineer (jump to about 21 minutes in): https://www.youtube.com/watch?v=2V6YN-mshmY

So perhaps a factor, but I feel the bulk of what I hear comes from the compression/limiting/de-essing done during the mastering process combined with a bit of wear. Perhaps it's because I'm familiar with how these effects can sound that I pick up on them? The stuff I tend to listen to has a reasonable spread of HF energy (like the Steely Dan on that video), which is tough to master for vinyl. Perhaps older stuff is better/easier, but I've no interest in pop/rock from the '60s or earlier...

In summary, the last thing a record player needs is excess HF, IMHO - when I get the chance to hear one, I might well approve of the GP42. But hey, we're all different... At least these sorts of machines have tone controls

[electronicskip]

I'm not sure if this strictly counts but I did have a Philips Car record player in a mini of mine.
Its sort of portable in a sense lol, but the sound was pretty good, whish I still had it.

[Edward Huggins]

Just to add to this, on my GP42 which I feel has a poor HF response, uses a Celestion unit. I don't know if this is better or worse that those fitted with a Goodmans in terms of treble extension. I did find a reference in an old Radio Magazine to an Elac 10" x 6" unit with a ceramic magnet, a treated cone surround and an aluminiumised whizzer cone. One of their last - I bet these will be as rare as hen's teeth by now!

[D_S_J_R]

My GP42 had a Celestion speaker and the 'port' at the back had some foam in it too (aperiodic loading? grin). I ran mine with bass backed off half way and treble pretty well flat out and it was pretty darned acceptable this way. A basic stereo set owned by a school-pal's dad ate it alive though, this system being an SP25mkIII/AT66 - Metrosound ST20 amp and Denton W20 speakers. I have Denton W20's here and an ST20 which hums on its outputs slightly too much to use. Both can sound charming in a slightly foggy kind of way and the Dentons surprised me how basically neutral they are.

Ah the memories...

[Edward Huggins]

I have learned to make the most of my GP42 by siting it "on axis" to the ears when seated. I use it on a very solid corner unit about 1 metre from the floor. The Bass needs taming in that location. It certainly gives a good, clear, rather hard "pentodey" forward, sound - but I still prefer the (extremely rare) Philco "Duet" with its Plessey (curved cone) 10" x 6", its seperate tweeter and in an elaborately vented cabinet.