But how can you, the other posters in this thread insist that all amplifiers sound the same,
I'm selling my Linn LK280 and buying a Rotel
I'll get my coat
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Again I ask have people who think that they hear differences tried an AB comparison with matched levels?
It's possible to make an amplifier sound different. There is no guarantee that the frequency response is flat. For instance the output impedance of Valve amplifiers driving real loads will cause frequency response irregularities which I can believe can be heard in an AB comparison.
I am assumimg that the Ferrograph amplifier is old and dates back to the time when solid state amplifiers were new and transistors were expensive. I can believe that it sounds different but it really belongs in a museum.
If an amplifier is linear it doesn't matter if it's music or a single frequency sine wave it should still just amplify. Refering back to the first sentence.
It's possible to make an amplifier sound different. There is no guarantee that the frequency response is flat. For instance the output impedance of Valve amplifiers driving real loads will cause frequency response irregularities which I can believe can be heard in an AB comparison.
I am assumimg that the Ferrograph amplifier is old and dates back to the time when solid state amplifiers were new and transistors were expensive. I can believe that it sounds different but it really belongs in a museum.
If an amplifier is linear it doesn't matter if it's music or a single frequency sine wave it should still just amplify. Refering back to the first sentence.
If apples were apples, that would be fair comment but now you're talking about more than just amplifiers. Some, like the Naim, have
a few little tweaks so they will indeed sound different. Most don't have such identifiable tricks as cause deliberate distortion.
It's no secret and clear enough on the schematics, if sometimes buried in folklore and enthusiast or marketing hype.
Tag Mclaren circuits are remarkably close to Self's Blameless model and devoid of sonic embellishments as would seem Rotel designs
but there are design "flaws" also giving rise to significant distortion which (I think) gives many Rotel amplifiers their character.
These aren't parts issues, I'd call them deliberate "colouring" of the sound. That virtually prevents fair comparison of many
commercial amplifiers but there are many forum designs that will sound identical, with low distortion and "untweaked" as they are.
Tag Maclaren circuits are way different to Self Blameless, the only resemblance being a input LTP.
Distortion in Rotels arent so significant as one may think, they are very conservatively rated on paper.
There is a lot more than the LTP similar with this one's big brother, the 250x2R monooblocs which are definitely in the family, albeit with the addition of a few limiters.
As I recall, these 125s follow suit, though I can't locate the schematic atm. Obviously each contracted designer brings their own topologies and so these and other concurrent models are indeed "Blameless" for one good reason.
Categorized Schematics and Service Manuals for free download S-UI have a small ROTEL, an RA1060 which, with fixed tones, is within spec. @ <0.02% THD as measured on a 24/192 soundcard. The IMD and HF distortion is more telling, at around .04% at 12W with a lot of products crowding into the mid and HF. Others use a CCS and current mirror on the LTP but ROTEL eschew it, to some effect, when paired with their triple output stage, I think. That gives the characteristic sound which is not hard to duplicate.
Most people probably think of the overkill ROTEL monsters as good examples but the character is more obvious in the smaller models that do get thrashed and show their weaknesses, if that's what they are.
Which then raises questions about alleged differences in sound between brands that share a common designer. (Although I thought Creek was mostly designed by Mike Creek himself)
Ok a bit of a side point, but what are the thoughts on the Tag design.
Whenever the Rotel was mentioned on here it did not receive a single positive comment.
Apparently flawed veiled design, that is not worth upgrading.
How is the Tag viewed by the group and is it worth playing with, or keeping stock?
Whenever the Rotel was mentioned on here it did not receive a single positive comment.
Apparently flawed veiled design, that is not worth upgrading.
How is the Tag viewed by the group and is it worth playing with, or keeping stock?
I did not intend to rubbish the Rotel, but is does have a deliberate "feature" that may give the Rotel signature sound. The TAG is a more neutral and accurate design, that many reviewers would complain about as bland, lifeless etc.
I am now thinking that the reluctance of modern manufacturers to let us near a schematic is more to hide the common contract designer than anything else. In the old days you could spot the house design of a Quad, Sugden etc a mile off and their owner/designers were proud to show their work
I am now thinking that the reluctance of modern manufacturers to let us near a schematic is more to hide the common contract designer than anything else. In the old days you could spot the house design of a Quad, Sugden etc a mile off and their owner/designers were proud to show their work
I agree with that.There aren't enough TAGs around to dive in and throw mods everywhere, though with any modded gear, it's instantly worth less than standard unless some well known expert has done it and you have the pedigee to pass on or such.
I don't think anyone has criticised the ROTEL combo. It's a price tag/respect thing there but as Homemodder said, they perform very well because of their conservative rating and I think generally, they do have a refined, smooth sound but I don't see how they could present a different balance of tone to other amps without serious frequency response faults, so unless they are EQ'd at 1 Khz or some other suitable frequency, I can't accept that there is such a massive (>3dB indicated) frequency response wobble or even distortion that creates that impression. I think these are the only options to consider and neither one would be acceptable in any commercial product.
You haven't said what mods you planned but if it's routine recapping, it shouldn't be a problem for resale unless you overdo it with crazy overkill, switchburning amounts.
Re. house designs: I think Stan Curtis - the ultimate contract designer/manager did just about all the early 70's/80s budget UK stuff for a big group of firms, Sugden among them. In recent years, they seem to rotate around the manufacturers more freely.
I don't think anyone has criticised the ROTEL combo. It's a price tag/respect thing there but as Homemodder said, they perform very well because of their conservative rating and I think generally, they do have a refined, smooth sound but I don't see how they could present a different balance of tone to other amps without serious frequency response faults, so unless they are EQ'd at 1 Khz or some other suitable frequency, I can't accept that there is such a massive (>3dB indicated) frequency response wobble or even distortion that creates that impression. I think these are the only options to consider and neither one would be acceptable in any commercial product.
You haven't said what mods you planned but if it's routine recapping, it shouldn't be a problem for resale unless you overdo it with crazy overkill, switchburning amounts.
Re. house designs: I think Stan Curtis - the ultimate contract designer/manager did just about all the early 70's/80s budget UK stuff for a big group of firms, Sugden among them. In recent years, they seem to rotate around the manufacturers more freely.
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This is strange, back in 1993 or 1994 it was one of the top amps to buy at the price range of 350 pounds and below. It recieved 5 star status in publications like What Hifi. It was later dethroned by the Marantz ki signature amps. I have three and I love them, a little tweaking makes them even better, sorry but the Self style amps do sound a little bland in comparison and needs lots of messing about to get nice sound out of them.
The best appraisel I found of this amp was when pitted against the older AKSA amp on a internet page, here the author just plainly said at the end that the aksa was nice but completly outclassed by the 970BX and it was more expensive. Makes one think..... and proves different strokes for different folks.
Everything you read on the interwebs is true.(R)
Did you ever see any kind of reliable evidence? Or just hot air?
Neither the schematic, which can be obtained here, nor the measurements carried out by Stereophile mag indicate bad performance - quite the contrary, in fact. The RB-991's measurements look nearly bulletproof.
The only thing I'd check (and adjust if necessary) is quiescent current. The adjustment procedure aims for a fairly standard 30 mA; you can try up to about 50 mA (a 10-11 mA) but do keep an eye on temperature then.
Hard to say without having an actual schematic at hand. I'd say it would take their 250 watter (the schematic of which you can find on the web) to compare to the Rotel though.
Their power transistors actually are quite comparable under the conditions used (as far as fT, beta and SOA go), except the Rotel has 5 vs. the TAG's 3. Instead, the TAG has built-in current limiting and protection circuitry (output relay included). IOW, "robustness via overbuilding" vs. "robustness via smart design". The Rotel would be expected to deliver more power into low-impedance loads though.
The TAG is a fairly conventional high-power amp design as far as voltage amplification goes - single LTP with cascode and current mirror, Darlington VAS, nothing to expect bad performance from. The output stage is only a double EF affair though, so I'd expect better load immunity (and low-impedance load driving) with the Rotel's triple EF.
Since it looks like the 125Ms also have an output relay, it may be advisable to give that one a good cleaning (no sandpaper unless the contacts are too far gone anyway) or replace it entirely. (Usually unsoldering is required before relays can be opened.) These are to be considered expendable parts in most cases. Contact problems in them can easily degrade damping factor to the point of audible frequency response deviations with a real speaker load.
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