I'm confused about today's amplifiers.

[mhardy6647]

I -- ahem -- just want to point out that there were many, many stereo (and, pre-stereo, also mono) integrated amplifiers containing nary a transistor.
The EICO HF-81 stereo integrated amplifier fairly leaps to mind -- silicon/germanium -free; even using vacuum tube rectifiers (two of them!) in the P/S.



The HF-81 had a complete stereo preamp as well as its two push-pull EL84 power amplifier sections on one chassis: tape head and MM phono preamp/EQ, tone controls, tape output (stereo) for recording, loudness (fixed, not variable) -- all most mod cons.

Innards of an HF-81 (not my amp nor photo):

 

[Hiten]

old school integrated amplifier
1) multiple input selector
2) bypassable tone controls
3) two pair of speaker selector with stereo, mono, reverse and A+B
4) headphone socket
5) level indicator
6) main in or pre out
7) balance control
8) microphone socket
9) couple of mains ac outlet at back

 

[Bruce Morgen]

Nobody would call this vintage Pioneer M90, an "integrated amplifier", yet it has three selectable inputs, stereo ganged Alps shaft driven "volume control", two selectable speaker outputs a line output and headphone jack.

Pioneer in specifications of Pioneer M-90

The same goes for my old Kenwood KM-8002.

 

[restorer-john]

The same goes for my old Kenwood KM-8002. View attachment 444339

That is a beautiful amplifier!

 

[Bruce Morgen]

That is a beautiful amplifier!

Thanks, John -- gone but not forgotten.

 

[Audiolab800]

Something like 2 FOSI Audio V3 fits the bill

Fosi Audio V3 Mono Amplifier Review

This is a review and detailed measurements of the Fosi Audio V3 Mono class D amplifier. It was sent to me by the company. The price with the power supply I tested is US $139.99. I must say the concept of a "monoblock" amplifier in such a small size runs foul of any expectation a longtime...

www.audiosciencereview.com

It is of Chinese origin and design, but uses a well known Texas Instruments chip.

Many options in that range. Almost too many to count.

You will be impressed with these small mono blocks…they perform very well, no idea how long they will last though. But sound wise spectacular…

 

[mhardy6647]

no idea how long they will last though.

ahh, there's the rub.

 

[Audiolab800]

ahh, there's the rub.

Yep but compared them with an Amplifier with at least 20 times the price.... And if one dies, it will cost me 150€ and not an arm and a leg.
Measured the temperature while in operation for a few hours, it was below 40 deg centigrade (not measured with labo instruments and ideal conditions :0) )

 

[mhardy6647]

Yep but compared them with an Amplifier with at least 20 times the price.... And if one dies, it will cost me 150€ and not an arm and a leg.
Measured the temperature while in operation for a few hours, it was below 40 deg centigrade (not measured with labo instruments and ideal conditions :0) )

But, sadly, sidestepping the issue of the rate of increase of electronic waste due to economic unfeasibility of repair.

 

[Willem]

These days, the confusion is even bigger with pre-amplifiers. The traditional function of those would be differential amplification for the different inputs and their vastly different input levels, with phono as the most obvious issue, the possibility to switch between these inputs, tone and balance controls, and volume controls, plus various filters.
With modern DACs, many have volume control and the option top switch between multiple digital inputs. So these have all the basics of a traditional preamplifier, but now for digital sources. Some, like the often praised RME ADI-2 DAC, also have extensive dsp tone controls, filters etc. So, as long as one is only using digital sources, these are simply superb modern pre-amplifiers. And yet, some snake oil pushers claim that one still needs a preamplifier for the best sound. If you still use analogue sources (I don't) there are of course also versions of these DACs that will have those analogue inputs as well.

 

[Audiolab800]

But, sadly, sidestepping the issue of the rate of increase of electronic waste due to economic unfeasibility of repair.

Not sure they are not repairable but they are way more efficient than many Amplifiers of type AB and sure in comparing with the beloved class A amplifiers.
But you have got a point, we should minimize the electronical waste.

 

[mhardy6647]

Not sure they are not repairable but they are way more efficient than many Amplifiers of type AB and sure in comparing with the beloved class A amplifiers.
But you have got a point, we should minimize the electronical waste.

Indeed.

BL/UF (as they say*), I am skeptical of the cradle to grave economics/impact of the Class D modules vs. Class AB. The devil is often in the details (as they also say).

Actually, and strictly FWIW, I am still a bit skeptical of the "way more efficient" claim. Certainly Class D is "way more efficient" at high power output than Class AB (we'll neglect Class A, which essentially defines the limit of low efficiency in power amplification ), but at idle and at low output power (which, in the real world, with actual loads, is where most power amplifiers loaf along when playing actual program material**), things are murkier.
I've yet to see real-world energy consumption data for Class D vs. AB head to head. I am just saying.

____________
* Bottom Line Up Front -- I learned that from an economist friend.
** the "tempest in a teapot" about meaningful amplifier power measurements highlights the murkiness around how to even think about power output quantification in a meaningful way. Cf.
https://www.audiosciencereview.com/...24-requirements-on-output-power-claims.58972/
(all 88 pages of it)

 

[raindance]

Thanks so much to everyone for your thoughtful replies. Things are becoming a bit clearer. DVinylfan, the system I'm thinking about would be a secondary one probably using a Quad 66 preamp that I've had in the closet for a few years (still works!). The rest is to be determined.

If your plan is to use the Quad with a modern amplifier, make sure the amplifier has the right input sensitivity. I'm not sure about the 66, but some of the Quad preamps only output about 0.5 volt rather than the 2 volts of more modern options.

Of course it would still work but could be volume limited.

 

[Mart68]

If your plan is to use the Quad with a modern amplifier, make sure the amplifier has the right input sensitivity. I'm not sure about the 66, but some of the Quad preamps only output about 0.5 volt rather than the 2 volts of more modern options.

Of course it would still work but could be volume limited.

The '66' is indeed 0.5V on the line out.

 

[Chaconne]

Thanks to raindance and Mart66 for that info!!

 

[AdrianusG]

That is a beautiful amplifier!

Hi John,

I have a direct question for you,
i could buy below Amp for around 675 Euro, (incl. shipping) condition is mint/as new , it's from a well known shop in Germany which i know and trust, warranty will be 6 months for this product

Is this a (still) a good deal, for this price?

You insight will be appreciated

They also have the Kenwood, which inc. shipping will be around 180 Euro up in price though, same conditions as far as warranty

Adcom GFA-555 II​

 

[AdrianusG]

Hi John,

I have a direct question for you,
i could buy below Amp for around 675 Euro, (incl. shipping) condition is mint/as new , it's from a well known shop in Germany which i know and trust, warranty will be 6 months for this product

Is this a (still) a good deal, for this price?

You insight will be appriciated

They also have the Kenwood, which inc. shipping will be around 180 Euro up in price though, same conditions as far as warranty

Adcom GFA-555 II​

View attachment 459885

To add, these pictures are from the actual product On Sale, so from the shop!

The Kenwood has a few visible damages (7,5-8/10) so not quite mint , but technical condition will be 100%

I,m also considering this Yamaha, and use it (for now) purely as Power-amp, condition 8,5-9/10
it will give me the bonus of a good Pre-amp as well (stages are fully seperable pre-out/Main -in)

That one will be shipped for Euro 559, same half year warranty

Question is more about long-term reliabilty than power, all 3 proposed power amps are more than enough for my requirements, so it comes down to, what would be the best deal overall?

 

[Graham849]

not sure if you have seen this https://www.audiosciencereview.com/forum/index.php?threads/yamaha-ax-1070.20362/

 

[tobyjug]

It would appear the OP has a preamp .
small-sized amplifier—what I think of as a "power amplifier," that is, a unit that sits between a preamp and speakers.

 

[Mr_RGB]

Hi John,

I have a direct question for you,
i could buy below Amp for around 675 Euro, (incl. shipping) condition is mint/as new , it's from a well known shop in Germany which i know and trust, warranty will be 6 months for this product

Is this a (still) a good deal, for this price?

You insight will be appreciated

They also have the Kenwood, which inc. shipping will be around 180 Euro up in price though, same conditions as far as warranty

Adcom GFA-555 II​

View attachment 459885

I have about a dozen amplifiers of various types including an original ADCOM GFA-555 and currently using FOSI ZA3s (with 48V 10A PS) as amps mostly because of their small size and the fact that they have a 12V trigger input. Unless you have very inefficient or hard to drive speakers I would give something like this a try. Note: tested with ADS L630s, L880s, and Large advents (all pretty easy to drive).