[ericohgb]

Quote:

 
I forgot to include the tool in the last shipment of 8 amps; i will be sending it out to all of those owners in an envelope.

Hi, Justin.
Mine came with no tool or instructions.
Could be so kind to send them?
I'll pm you my data.
Regards,
Erico

 

[David1961]

Quote:

I'm very pleased about that. It was one of the things I was concerned about - the BHSE sometimes being compared to a space heater.
 
With around 250w power consumption,spread over 2 boxes, and a fair proportion of heat coming directly from the tubes, I just couldn't see how the boxes themselves could get that hot. Just not enough watts to go around. Justin increased the ventilation holes in the current 50 batch, so maybe the previous batch did get a bit hotter.
 
My BHSE is allegedly going to be "in the post" pretty soon now, so I'll find out for myself.   

From what I've heard the temperature the BHSE gets to, does depend on the amount of voltage coming from whatever the mains is supplying. However while the boxes I have get nice and warm, the tubes do get quite hot.

 

[ericohgb]

Quote:

From what I've heard the temperature the BHSE gets to, does depend on the amount of voltage coming from whatever the mains is supplying. However while the boxes I have get nice and warm, the tubes do get quite hot.

Indeed.
Do not let your dogs bite them!

 

[David1961]

Quote:

Indeed.
Do not let your dogs bite them!

My Dogs are too busy enjoying themselves, plus I do feed them well. That's why every time I take them to the vets I'm told they need to lose weight.

 

[vvs_75]

[size=medium]In my experience the most challenging part during the BHSE voltage regulating is the inserting and keeping millimeter probes in the headphone jack. The pin holes are too close and the probes are too fat to fit nice and secure. It’s not very convenient to keep probes in the jack with one hand and trying to adjust sensitive trim pot and at the same time keep an eye on the millimeter screen, probes and trim pot. [/size]
 
[size=medium] So to make the job a little bit easer and safer I made adapter/tool for it.[/size]
 
 
[size=medium][/size]
 

 
 
 
[size=medium]Simply plug it in, hook the ez-probes hooks to the marked wires and your hands are free. Every wire has a different length size so there is no chance for an accidental short.[/size]
[size=medium]At the time I have to use whatever I have at hand to make it but it’s much easier just to use Allied plug for the job.[/size]
 
[size=10pt]WPI - 86-71-6S - Allied Electronics[/size]
 
[size=medium]BE AWARE![/size]
[size=medium]Do not adjust the BIAS voltage on BHSE through the headphone jack.  It must be done at the PSU; (I would not touch it at all) there is a place on the PSU board near trim pot for the probe, where you take the measurement from.[/size]
[size=medium]  In my unit the actual required 580V bias will show only about 326V at the jack. So if you make 580V at the jack you will have 800+V and that will damage your headphones.[/size]

 

[cobra_verde]

Thanks for the tips VVS. I'm not sure I understand the part you have after Be Aware. Is that something different than what you built your tool for? Can you explain that last part again? I'm thinking about buying a BHSE but all of these adjustments are kind of intimidating. Yet, I still want to give ownership and all of these adjustments a try. Thanks!

 

[vvs_75]

[size=10pt]The BE AWARE part is not related to the tool. I just mentioned it just in case if somebody will try to adjust bias through the jack. [/size]
 
[size=10pt]You should not be intimidated, when you get the amp just put tubes in marked positions and you are done. You do not need to adjust anything. This is for the folks who like to experiment with sound, the BHSE amp was designed to sound best with any tubes and the stock tubes are good. Hope it helps.[/size]

 

[justin w.]

Quote:

Thanks for the tips VVS. I'm not sure I understand the part you have after Be Aware. Is that something different than what you built your tool for? Can you explain that last part again? I'm thinking about buying a BHSE but all of these adjustments are kind of intimidating. Yet, I still want to give ownership and all of these adjustments a try. Thanks!

 
All of the Stax amps have these same adjustments, they're just inside the box, requiring it to be opened before you can adjust anything.  I'm sure 99% of the owners never make any adjustments.  In the BHSE, the adjustments can be made without disassembling any part of the amp.  It's really optional unless you install a very different set of tubes.  Even then the amp will still work and you're unlikely to know that any adjustment is needed.

 

[forbigger]

Justin, CMIIW, what you implied on your post above is that anyone can pop in any EL34 to BHSE without the needs for adjustment? And to ensure that the tubes are matched but thats another whole issue altogether.

 

[cobra_verde]

Thanks VVS and Justin: both answers are helpful.

 

[Elysian]

What's the downside of not doing the adjustment when going from something like the stock EL34s to 6CA7s?

 

[justin w.]

Quote:

Justin, CMIIW, what you implied on your post above is that anyone can pop in any EL34 to BHSE without the needs for adjustment? And to ensure that the tubes are matched but thats another whole issue altogether.

 
Adjustment may be needed for optimal performance.  The whole reason I am hesitant to really walk people through the process is that "any EL34" tube quickly becomes "any large tube that fits in the socket" and then things start blowing up

 

[googleli]

I am really confused now. Someone posted a while ago a simple method using the headphone jacks to do the adjustment. Then someone pops up and say with capital letters DO NOT do it at the headphone jack, and that it should be done at the PSU. I think Justin should at least clarify (1) whether the previous headphone jack method works and (2) how not to get electrified when using the PSU method... 

 

[sridhar3]

Who the hell cares?  Just use the trim pots.  That's why they were put there in the first place.

 

[justin w.]

Quote:

I am really confused now. Someone posted a while ago a simple method using the headphone jacks to do the adjustment. Then someone pops up and say with capital letters DO NOT do it at the headphone jack, and that it should be done at the PSU. I think Justin should at least clarify (1) whether the previous headphone jack method works and (2) how not to get electrified when using the PSU method... 

 
It's referring to 2 different adjustments.  The only thing you can adjust at the PSU is the headphone bias voltage.  There is no reason to adjust this.
 
The DC balance/offset adjustment can be done with a 1000V-capable DC Voltmeter at the headphone jack, and adjusting the trim pots on the top of the amplifier.