HK A300 What should I know?

[erickrb]

Hey everyone,
I'm potentially getting a Harman Kardon A300, that's been recently recapped. I'd be pairing it with a pair Klipsch Forte I. I know tubes are supposed to be great with Klipsch's. I also have a Pioneer PL-50 (the old one, not the PL-50L)
If so, what do I need to know since it'll be my first tube integrated amp? I know to only power it on with the speakers hooked up. Anything else? Where can I find out more about Tubes, and what tubes work with this receiver and can make them sound better for the future? I'm sure this will be a rabbit hole.
Thanks.

 

[GordonW]

Even though this thread will probably be moved to Dollars and Sense- IMHO, that's a "run, don't walk" deal. Get it before it's gone!

Output tubes are four 7408, which are the same as 6V6GTA, and the other tubes are four 12AX7s and one 12AU7.

If it's got the factory Telefunken- built 12AX7 and 12AU7 tubes, it will be hard to improve upon that.

Regards,
Gordon.

 

[erickrb]

Thanks for the advice Gordon, I'll look into those tube.

With the Klipsch Forte I's am I correct to use the 8 Ohm output? Do I need to use spade connectors or can I wrap the wire around the screw? Am I correct that I should NOT turn on the receiver until the speakers are attached. Is there anything else I need to know before owning my first tube audio? Thanks.

 

[trainbuftony]

You are correct on the dont turn on without speakers.
I would refrain from wrapping bare copper arround the screw, the strands tend to splay everywhere.
I buy my spades in lots of 100 from a local hardware store, they are good quality and about 7 cents a piece. I solder them on and heat shrink over the joint with either red or black heat shrink.

Use the 8 ohm tap, but don't be afraid to try the 4 ohm or 16 ohm tap. It cant really hurt anything.

 

[FlaCharlie]

what do I need to know since it'll be my first tube receiver? I know to only power it on with the speakers hooked up. Anything else? Where can I find out more about Tubes, and what tubes work with this receiver and can make them sound better for the future? I'm sure this will be a rabbit hole.

Welcome to AK!

I'd suggest you go back and edit your first post and remove the reference to price. Otherwise the thread will be moved to a different forum which doesn't get as much traffic and, hence, you're likely to get less help with other questions. The "Edit" link is at the bottom of the post.

BTW, the A300 is an integrated amp. An integrated only has an preamp and amp section while a receiver also has a radio tuner section.

 

[erickrb]

Looks like the power tubes are all 6v6 GTA, with 4 preamp tubes being 12AX7, and the other one is an HP 5963. Should I be concerned about about the HP tube?

Is it ok to remove to the preamp tube heat shields, so they can be seen, or are they needed?

I ordered some spade connecters, I'll attach those and us them. Thank you for the info so far.

 

[RossW]

The 5963 is a good enough sub for the 12AU7 although opinions are mixed on how they sound.

The metal shields reduce noise pickup in the small signal tubes, plenty of people run without them and some amps don't have them to begin with. If you don't get hum or other odd noises with them removed you can leave them off.

 

[erickrb]

Thanks for the great info everyone. Last question... which channel is right and left. They only say A or B. And the rca ports aren’t color labeled or marked left or right. There’s on on the back and one on the top. Thanks.

 

[GordonW]

The only issue, is that while the 12AU7 is rated at 300v steady-state and 1200v peak, the 5963 is only technically rated at 250v, whereas the circuit in the A300 with the 12AU7 (phase inverter) has 325V feeding it.

That won't be an issue while the amp is running (the steady-state operating voltage across the tube is only about 180v)- but it could be an issue at startup, before the tube heats up and starts conducting- it will see all of the 325v between the plate and cathode, for a few moments each time the amp is turned on.

Regards,
Gordon.

 

[buickguy62]

Thanks for the great info everyone. Last question... which channel is right and left. They only say A or B. And the rca ports aren’t color labeled or marked left or right. There’s on on the back and one on the top. Thanks.

Generally on the A300, as you look at the amp from the front, the A speakers are positioned on the left, the B speakers are positioned on the right. (the speaker wires cross behind the amp). Every so often, the internal wires are crossed, if so, the balance control,operates opposite of normal. If so, just switch the A and B speaker wires.
For inputs, the A channel is on the top of the chassis, B channel is on the vertical rear chassis.

 

[David_NC]

I recently finished refurbing an A300 (actually the A30K kit version). It is probably the easiest integrated tube amp to work on; lots of room, basic circuitry, etc. Mine currently has Magnavox 6V6GTA's and an assortment of vintage 12AX7's and 12AU7, but I can't remember the brands.
Although it's only rated at 12 watts / channel, it powers the speakers I've used with it quite well. These range from 86 to 93dB efficient. So far, I really like this amp. It has some of the best detail and imaging I've heard in a long time. Often, it seems like I have surround speakers when sounds come from areas nowhere near the speakers. As long as it properly powers the speakers I use with it, I think this is a keeper. I will say that the bass isn't as strong as it is on my other amps (7591 Sherwood S5000II and EL84 Pioneer ER-420). I use a powered sub with it, so it's really not an issue. The Channel A and B thing buickguy62 mentioned on the back was confusing at first, but I simply penciled an L and R on the chassis to make that a non-issue.

 

[erickrb]

So far, I really like this amp. It has some of the best detail and imaging I've heard in a long time. Often, it seems like I have surround speakers when sounds come from areas nowhere near the speakers.

I believe it! Was listening to "Time", and swore I heard a clock behind me. I'm using it with a pair of Klipsch Forte, so plenty strong for those.