BHK Preamp and heat generation


#1

Hi folks, newbie to these forums and PS Audio in general. I’ve been looking for a preamp for awhile having gone through too many to count in recent months. My favorite has been the Ayre K-5xeMP thus far although I’m currently using a Pass Labs XP-10 that I’m not entirely enamored with. I’ve been drooling over a BHK pre ever since the reviews started rolling in, and the Black Friday deals finally tipped me over the edge. I’m very excited for whenever it arrives (dealer said they’re shipping directly from Colorado as he doesn’t have any in stock with the sale cleaning out his inventory).

One question I have is: what’s the heat output like on the BHK preamp? I’ve experienced a few tube integrateds and headphone amps that put out crazy amounts of heat (PrimaLuna comes to mind), but I’m not sure what to expect from a tube pre that only utilizes tubes in the input stage but also as part of the voltage gain for volume control. I have a relatively small listening room and it can get hot in our sultry southern summers which is why I run a Class D power amp. Any word on how much heat the BHK pre produces compared to solid state preamps?


#2

The Ayre is an excellent piece and one of the few I think in a league similar to the BHK - just less rich. The heat’s there in BHK, not excessive, but if you put your hand on top you know it’s a tube. I am not sure how to best tell you an exact number but it does make heat. And magic.devil_gif


#3

I did love the Ayre, but am more than excited to try the BHK. Added richness is exactly what I’m looking for in my system, especially if it comes without a hit to transparency or separation.

Thanks for the feedback, Paul. It sounds like it should be fine for my room, but at least I’ll have until March or April to find that out!

Just got the shipping notification. Woohoo!


#4

I live in S. Florida where it’s a gazillion degrees every day during the summer. Neither the BHK preamp or amp added much heat to a naturally toasty living room. In my setup it never got any more than slightly warm to the touch.


#5

That’s great to hear. It gets nasty here in the summer but without the extreme humidity I know you Floridians have to deal with. Appreciate the response. Really looking forward to this preamp.


#6

My BHK Pre sitting on top of a P10 has reached 109º Fahrenheit. Between this and my BHK 250, it got uncomfortably warm during summer. AC and fans took care of the mid-day heat but unfortunately the noise was a problem. I ended up doing a lot of late night listening sessions.


#7

@sevilla

Out of curiosity, does the P10 generate any heat itself?


#8

The regenerators are essentially amplifiers emitting a single tone of either 50Hz or 60Hz depending on your country. (Amplifiers send speakers AC current of modulating frequency). Thus, they generate heat.


#9

Having lived with BHK pre & 300 mono’s for a few months, I cannot see heat being a problem with this product.

… but I like my P10 to run @ 50% max :slight_smile:


#10

Agreed, the heat generated should be of no consequence.


#11
wasquatch said

@sevilla

Out of curiosity, does the P10 generate any heat itself?


Yes, the P10 gets hot too. It runs about 40-45%. My DSJ Junior gets hot too, now that I think about it. To clarify, the heat produced by my sound system is not the problem. Even my TV produces heat for that matter. The real problem is my 1957 ranch house with no insulation and original single pane windows. My window AC does a good job of cooling down my listening space during the hotter times at the expense of blaring noise. I solved my problem by becoming a nocturnal audiophile.

#12
My BHK250 also runs quite warm, but not hot. By comparison, my dual McIntosh MC275 tube amps could heat a small room. For the Macs, and now the BHK250, I’ve been using two silent mini-fans that connect to a dual USB plug connected to a corded lamp switch. This arrangement allows me to operate the fans remotely. The fans are placed behind the BHK and flank the heat sinks. As a result, the sinks have merely a gentle warm feel. The fans, dual USB plug and remote lamp cord are all available on Amazon for a total investment of about $40. The caveat is to get “silent” fans, of which some are more so than others. My fans are not totally silent, but don’t intrude on the sonic performance. The amp cooling gives me peace of mind, though as mentioned, it doesn’t run excessively hot even absent the fans.

#13
roadsterluver said
I’ve been using two silent mini-fans that connect to a dual USB plug connected to a corded lamp switch. This arrangement allows me to operate the fans remotely. The fans are placed behind the BHK and flank the heat sinks. As a result, the sinks have merely a gentle warm feel. The fans, dual USB plug and remote lamp cord are all available on Amazon for a total investment of about $40.
Do you have more details on these fans? Maybe an Amazon link?

#14

In my experience (and my application/setting etc…) both the BHK pre and 250 do generate some heat - even at standby which is to be expected.

Just to be safe and have ease of mind, I also installed electronically controlled fans for both in my stand. After asking around I got the recommendation to go for larger diameter lower RPM fans designed to be very silent. For the BHK 250, I have dual 120mm Gentle Typhoon fans in a pull mode behind the amp with a temp sensor just above one of the amp heat sinks. For the preamp I have a single Gentle Typhoon behind the amp pulling air out and a tiny Noctua fan just above to push a little breeze, so they work in push-pull. They are practically dead silent and keep things cool. Each set of fans is controlled independently by its own temperature control unit.


#15

Rayk

The fans I’m using are the “Arctic Breeze USB” fans going for under $15 on Amazon. They have an adjustable speed control at the base and are pretty quiet. I’ve also used fans similar to the Gentle Typhoon mentioned by odysseas with very good results. These are also on Amazon for under $25. If you decide to use fans, factors to consider are the absence of noise, fan mounting (some have stands, other don’t), powering on and off if placed behind the amp, and connectivity (I use USB connected fans). I’ve actually gone through a number of fans with varying degrees of satisfaction, but their cost on Amazon is so reasonable that it’s no big deal. And, of course, there’s the added benefit of finding yet another audio-related obsession.

They really do a nice job of cooling the surfaces of the BHK amps and, for me, are non-intrusive.

Cheers.


#16

Does anyone have ideas on the optimal (lowest noise, least problems) temp for the tubes? I read 94 deg F on top center, just in front of grill.

BHK Sig Preamp

Brett