Dayton Audio HTA20 Hybrid Tube Amp Review

[kharan]

This is fine, why would I buy a tube amp if not for the distortion and the funky FR?


If I wanted performance and straight wire with gain, the 3e Audio A5 is about the same price and rolls all over it in any imaginable objective metric.

 

[Sokel]

If I wanted performance and straight wire with gain, the 3e Audio A5 is about the same price and rolls all over it in any imaginable objective metric.

Imagine one with the upcoming(?) chip, chip-amp as the TPAs are near (or passed) their 10th anniversary.
Thing is that thread's amp is no way representative, it's more of a Dr Frankenstein's design will all this mixed tech.

 

[totti1965]

To call these things merely "not bad" would be an insult to all not-bad amps:
Look just at the high frequency noise, using USB: This is Jitter in its most extreme form.
Apple solved this in their Headphone dongles for just US$ 10!
And: Come on, 50 Hz to 12 kHz frequency range.
Is this really HiFi?

 

[beagleman]

I have not owned any tube equipment for well over 30 years, but from memory, my old tube receivers tended to have a VERY FULL bass sound, that maybe did roll off around 30 Hz and treble that was a bit muted but still "normal" sounding for the most part. Just more of a wooly "Fuller" sound.

Nice in a way but not high fidelity. This one has NONE of that boosted full bass sound of the stuff I owned.

 

[beagleman]

To call these things merely "not bad" would be an insult to all not-bad amps:
Look just at the high frequency noise, using USB: This is Jitter in its most extreme form.
Apple solved this in their Headphone dongles for just US$ 10!
And: Come on, 50 Hz to 12 kHz frequency range.
Is this really HiFi?

Oddly enough, many vinyl records of the 50s and 60s bragged about having 50-15,000Hz sound.

 

[Sokel]

Oddly enough, many vinyl records of the 50s and 60s bragged about having 50-15,000Hz sound.

Why would they do that when they did perfectly nice 20Hz-20kHz?



1954 Also Sprach Zarathustra Op. 30 - Sunrise

 

[Proberts911]

FYI, this amp has 440 reviews on Amazon alone! Average rating is 4.5. These products remain so popular.

Every product on Amazon is rated 4.5 or higher. Ratings always skew to the hi side. It's an impressive looking product to the uninitiated.

 

[ClaudeJ1]

Wow, 189 dollar to get that true “musical” tube sound with some nice and warm distortion.

I have to laugh at your post. Dripping with sarcasm, perhaps?

I go back to buying used tube stuff and music audio cassettes (before Dolby Noise reduction). Even my parents' console Philips Stereo cabinet with ceramic cartridge (with small magnet woofers and tweeters not isolated from each other) sounded better. All before the original walkman. We still enjoyed the music.

I have to remind everyone that based on 1971 US Dollars, A dollar is not worth a 1971 dime via FedGov INFLATION. So this amp, in my mind is only about $19, which I could have paid for with 10 day's worth of my paper route money while in Jr High school.

We have all been spoiled, lately, by Chinese made, TI 3255 based, class D chip amps, like the Ayima that you can get for $80/2025, ($8 in 1971 money). Now powering all of my all horn HT surrounds.

Everything should be taken in proper PERSPECTIVE!!!

 

[JeffS7444]

Why would they do that when they did perfectly nice 20Hz-20kHz?

View attachment 484261

1954 Also Sprach Zarathustra Op. 30 - Sunrise

With a typical 1954 cartridge and speakers?

 

[Heinrich]

"Very low output impedance", maybe a fake tube amp/. I'm not saying, but it raises my suspicion, and not the least the clean distortion spectrum adds to that.

 

[Sokel]

With a typical 1954 cartridge and speakers?

Maybe no.
But professional tape decks (15 ips) could so 20kHz just fine.

 

[Sokel]

"Very low output impedance", maybe a fake tube amp/. I'm not saying, but it raises my suspicion, and not the least the clean distortion spectrum adds to that.

Already at the first page, the amp is class D, not tube.

 

[mhardy6647]

the vacuum tubes, if they are active elements in the circuit at all* are likely used as voltage amplifiers, as someone said (or speculated) early on.
Do "we" know the operating points used for the tubes in this amp? Plate voltage and current, bias, etc.
While realizing that all generalizations are false**, oh-so-many of these cheap vacuum tube-contaning "hifi" audio components use such weird operating points as to render the tubes weird little glass-bottled effects boxes.

source: https://www.worldradiohistory.com/B...ooks/RCA-Receiving-Tube-Manual-1963-RC-22.pdf

source: https://www.diyaudio.com/community/threads/12ax7-in-parallel-datasheet.308340/
but probably lifted from an RCA Receiving Tube Manual by the looks of it.
_______________
* there is ample precedent for some pretty funny shenanigans with vacuum tubes in cheap components (e.g., using the filaments as resistors in the circuit, so that the tubes were required for function but didn't do anything as active circuit elements!). This being said, I don't think the titular "Dayton" amplifier is one of them.
** including this one!

 

[JeffS7444]

Maybe no.
But professional tape decks (15 ips) could so 20kHz just fine.

But we were discussing home hifi, not the cutting edge of professional recording technology. High fidelity recordings made with AEG's Magnetophon date back to the 1930s and 40s, but this was not consumer-level stuff! By the 1950s, I figure if a hobbyist had electronics (but not necessarily recordings or transducers) with flat response to 15 kHz, that would've been pretty elite. Flat 20 Hz - 20 kHz for audiophiles is really an early 1980s digital phenomenon.

 

[mhardy6647]

I also feel compelled to mention that it was fashionable for a while to run tubes like a 12AX7 (or even some of the neither fish-nor-foul Chinese small signal tubes that have no exact "western" counterparts) at really low plate voltages, taking advantage of the "space charge effect" to make very wimpy but (barely) functional amplifiers.

It's a bit off-topic but in the last days of vacuum tube car radios there were a number of specialized "space charge" tubes developed for automotive use. While "good" (inexpensive) audio transistors were available by the very early 1960s, transistors for high frequency (RF and IF amplifiers and oscillators) applications were uncommon and/or expensive. Hybrid tube/transistor car (AM, mostly) radios became moderately and briefly common in those economically-challenging times. There was intense interest in getting away from noisy, heavy, expensive and somewhat unreliable "vibrator" power supplies, so a family of vacuum tubes designed to run with a plate voltage of ca. 13 volts (car DC system voltage) were developed. Lots of them were made, relatively few were used, and they were (and to some extent are) available NOS at very modest prices. These appeal to the DIY/lunatic fringe vacuum tube hobbyists. See, e.g.,

Space Charge and Other Low-Voltage Tubes

Tube projects don't always require lethal voltages! Some tubes were designed to run at 12V. Others were not but work well anyway at B+ down to four volts.

www.junkbox.com

Much more recently, engineer/audio designer Pete Millett, e.g., designed an entry-level hybrid headphone amplifier/linestage using a space charge triode and a solid state buffer as a way for the true neophyte to play with a vacuum tube audio amplifier without having to worry about those pesky lethal plate voltages!
Here's the original morph, in a "reprint" of the original audioXpress article at Pete's website:

http://www.pmillett.com/file_downloads/ax_hybrid.pdf

He latter updated the design, but the only one I have experience with is the original.

Apropos of (almost) nothing: here's one of the several I've built, with a blue LED pilot light and illuminated with a blue LED flashlight.

 

[Sokel]

But we were discussing home hifi, not the cutting edge of professional recording technology. High fidelity recordings made with AEG's Magnetophon date back to the 1930s and 40s, but this was not consumer-level stuff! By the 1950s, I figure if a hobbyist had electronics (but not necessarily recordings or transducers) with flat response to 15 kHz, that would've been pretty elite. Flat 20 Hz - 20 kHz for audiophiles is really an early 1980s digital phenomenon.

The post which I answered was not about gear but about records.
And if it's on the tape I see no reason not to be on the record.

 

[Endibol]

To call these things merely "not bad" would be an insult to all not-bad amps:
Look just at the high frequency noise, using USB: This is Jitter in its most extreme form.
Apple solved this in their Headphone dongles for just US$ 10!
And: Come on, 50 Hz to 12 kHz frequency range.
Is this really HiFi?

Of course it isn't!

 

[SuicideSquid]

But we were discussing home hifi, not the cutting edge of professional recording technology. High fidelity recordings made with AEG's Magnetophon date back to the 1930s and 40s, but this was not consumer-level stuff! By the 1950s, I figure if a hobbyist had electronics (but not necessarily recordings or transducers) with flat response to 15 kHz, that would've been pretty elite. Flat 20 Hz - 20 kHz for audiophiles is really an early 1980s digital phenomenon.

To be fair, by the late 60s audiophiles had access to R2R tape players and solid state amps that would give you pretty solid 20Hz-20kHz performance but they certainly weren't mainstream.

 

[Linnie]

Could you do better job with that tiny output transformer? The transformer is what makes tube power amp performance. It makes no sense to produce such a small tube power amp. Other than "tube sales" rule.

I think we have here a basic law of audiophiles. When it's bigger and heavier it sounds better but costs more. A rule that has been followed by audiophiles since the tube days through the transistor age until the present day.

 

[JeffS7444]

And if it's on the tape I see no reason not to be on the record.

Typical record was bandwidth-limited and dynamically compressed in order to be playable on the majority of record players and to optimize playing time. Spectral analysis of LP playback may show "something" at the frequency extremes, but I think 30 Hz to 15 kHz is a more realistic, even really good, figure.