yay! - new toy - HK 'Allegro' A10

[markus]

Just came back from one of my 'secret locations' ara:

saw another old timer friend of mine; he usually has just vintage radios & tubes, but TODAY he had a very clean Harman Kardon A10 'Allegro' Mono Integrated tube amp Got it nice and cheap too

EZ80 rectifier, EL84 outputs (PP), and 2 ECC83's - ALL BUGLE BOYS :thmbsp:

brought it up slow, and there is an 'oh-so-slight' hum - just means I have some more caps to add to my next bulk order. Overall, even with the hum, sounds real nice. You can only hear the hum if you put your ear right next to the speaker . . .

this might be the new 'kitchen amp' running my little orphan Minimus 7W

 

[ldatlof]

beddy beddy nice find Markus. I like HK tube stuff.

I'll be in Pittsfield in early August. Is that anywhere near your "secret locations"? LOL

 

[markus]

'bout an hour & half I think :scratch2:

BUT - there is a cool guy in Lee MA with lots of vintage coca cola machines / signage / etc . . he sometimes has vintage audio, but not usually . . he'd be about 20 minutes south on route 7

 

[radioactive]

nice little amp there markus .

 

[ldatlof]

'bout an hour & half I think :scratch2:

BUT - there is a cool guy in Lee MA with lots of vintage coca cola machines / signage / etc . . he sometimes has vintage audio, but not usually . . he'd be about 20 minutes south on route 7

Thanks for the info... I'll definitely check it out.:yes:

 

[SixCats!]

Hi MARKUS,

Sweeet! Nice lil' looking MONO HK Amp! Let us know how it sounds.
I too have a lead on some HK gear however, as of yet, I dont' know as if it is tube or SS. Man, is my wife gonna KILL me!

Regards,
SixCats!

 

[markus]

Hi MARKUS,

Man, is my wife gonna KILL me!

Regards,
SixCats!

I think this needs to be your signature from now on :twak:

yeeaaah - I need to get it on a nicer speaker to see what it can REALLY do :thmbsp: luckily, my wife is out of town, so I get to scatter my audio eqipment in the sunroom

 

[WopOnTour]

Great find!
My advice would be to FIND ANOTHER A10
A PAIR of Allegros makes a real nice "integrated" mono-block setup
(especially if you're fond of EL84s as many are)
Here's what my pair looked like after I was done with them
They sounded GREAT with just my Nano and a pair of LaScalas
(I sold them locally for $400)

Wop

 

[radioactive]

yep you need to find another one.like wopontour said many people like the el84 and the allegro is a sleeper IMO .many people go for the more well known eico hf 81 but the allegro holds its own against it.(i know i onwed both)as for a kitchen setup i think the allegro deserves better than the minumus 7's:yes mabe some a klipsch hersey)

chris

 

[SixCats!]

Hey Markus!

Ooooou! I forgot that you had a MONO HK Amp!
Ummmm...what to swap what to swap ? lol

Regards,
SixCats!

 

[markus]

Great find!
My advice would be to FIND ANOTHER A10
A PAIR of Allegros makes a real nice "integrated" mono-block setup
(especially if you're fond of EL84s as many are)
Here's what my pair looked like after I was done with them
They sounded GREAT with just my Nano and a pair of LaScalas
(I sold them locally for $400)

Wop

WOW . .. those came out GREAT :thmbsp: funny you should mention the monoblock idea, since waiting in the wings, I have THESE:

http://www.audiokarma.org/forums/showthread.php?t=83995&highlight=steelman

From what I've gathered, these have HK circuit boards & iron. The first one came with all HK branded Amperex tubes too :thmbsp: I had originally wanted to pull the amp boards from these Steelman Mono AM/FM receivers, but the more I mull it over, the more I'd want to do something as you have with those little HK's.

As for the Allegro, I'm looking at mine right now . . . IT'S SO CUTE !

 

[wajobu]

That'll clean-up REAL nice there Markus!

 

[WopOnTour]

WOW . .. those came out GREAT :thmbsp: .

Yea they really didnt take much work...

Besides general cleanup and new knobs, I replaced that large horizontally mounted Astron 20/40/100 electrolytic , the .25uF paper decoupling cap on the input 12AX7 and the pair of .02uf output coupling caps into the EL84s (swapped the cheezy micas HK used here for some Solen PPs) and that was about it. They sounded REAL GOOD but hummed quite a bit at high volumes...

What I found was those red colored circuit boards both seemed to be very "oily" (see pic) which I attributed from that horizontal electrolytic leaking out all over the place.I cleaned the entire circuit board carefully on BOTH sides with "Safety Wash" degreaser and THE HUM WAS TOTALLY GONE. So I figure the oil it must have been causing ground loops or partial continuity between some components.

As for the Allegro, I'm looking at mine right now . . . IT'S SO CUTE !

AGREED! What I really liked about the Allegro was it's dimunitive size and BIG RICH EL84 sound (well, more than big enough with 105db Lascalas actually) The transformers are actually quite hefty for such a small unit making the A10s quite heavy for their size. These guys really are a little diamond in the rough and generally "dismissed" on eBay often selling for <$75. IMO they sounded much better than the A-230 Ballad I have.
If I ever find another decent pair- I'll keep them!

If anyone needs a copy of the A10 OM or schematic just shoot me a PM with your addy

WopOnTour

 

[markus]

WopOnTour:

great work :thmbsp: did you end up replacing alot of the resistors and / or caps on the circuit boards when you restored these A10's ? on the Steelmans (HK circuit boards) I have I definitely need to do coupling caps and PS caps; the other I haven't tinkered with yet -it was off ebay, and has a burnt resistor - it came with no tubes :tears: but I have spares

 

[WopOnTour]

No resistors. They all tested fine.On the circuit board just the red paper/oil you see in the pic and the 2 mica/disc coupling caps that you see just to the right of each EL84. The cicuit boards are well made and and take repeated soldering cycles without issue. ( I originally replaced the micas with new "like kind" units but felt the mids were a bit "dry" so I popped in a pair of Solen SM series polyprops for like $5 ea and it really brought the midrange to life!)

Those Steelmans look nice! Looks like they migh be HK iron as well.:thmbsp:
If the cathode resistor was smoked make sure you test the primary resistance of the output trannies.Do you have a schematic??
WOT

 

[nicholaspete]

hi yeah i could do with a schematic of the hk a10 - i just picked one up and boy does it sound sweet thru an old goodman axiom 100 i have in a cabinet ..

 

[David Bright]

Just came back from one of my 'secret locations' ara:

saw another old timer friend of mine; he usually has just vintage radios & tubes, but TODAY he had a very clean Harman Kardon A10 'Allegro' Mono Integrated tube amp Got it nice and cheap too

EZ80 rectifier, EL84 outputs (PP), and 2 ECC83's - ALL BUGLE BOYS :thmbsp:

brought it up slow, and there is an 'oh-so-slight' hum - just means I have some more caps to add to my next bulk order. Overall, even with the hum, sounds real nice. You can only hear the hum if you put your ear right next to the speaker . . .

this might be the new 'kitchen amp' running my little orphan Minimus 7W

can you connect a record player to this?

 

[tuberadios69]

The front panel selector switch has a source labeled RIAA Phono, so I'd say that confirms a built-in phono preamplifier.

 

[buickguy62]

I've restored and sold several A10's, often paired them with the FA10 receiver, which generally can be bought for less than the A10. (One on the Bay now has an opening bid of $100, no takers). Makes a nice sized stereo setup, can feed from the FA10 to the A10 for mono FM on both units. My experience is that some A10's hum regardless of how much you do to try to eliminate it. Hum increases with volume position. Of course speaker sensitivity plays a big part. Easy to recap, nice size and good sounding units.

 

[WopOnTour]

Ha! nearly 17-years later
I just bought another pair of these on eBay for only $119!
They a little rough but not too bad
Might just gut them and wire up a little SxS twin drive stereo chassis
WOT