BRYSTON BHA-1 HEADPHONE AMPLIFIER

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mav52

Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1240 on: 21 Aug 2020, 12:09 pm »
Hi Samjay!

You might try removing the pot from the shaft (there is only one screw that holds it in place) and use a very small amount of WD-40 or some specialized agent for electrical contact rejuvenation. I found this to be the case with my BHA-1 which is a very early S/N unit. Lots of things can contribute to this and in my case, it is extremely high humditiy where I live. 97% relative humidity at +40C can't be a good thing for anyone or anything, can it?

Most conventional volume potentiometers are like this and they require frequent use and in some cases, periodic maintenance.

Cheers,
Antun

Don't use plain old WD-40 it will gum up the area later on. Use something like WD-40 Specialist Electrical Contact Cleaner or DeoxIT

Grit

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1241 on: 23 Aug 2020, 09:54 pm »
Don't use plain old WD-40 it will gum up the area later on. Use something like WD-40 Specialist Electrical Contact Cleaner or DeoxIT

+1

There are several other electrical component specific cleaners. There's almost always a better more application specific choice than WD40.

Jozsef

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1242 on: 27 Aug 2020, 04:38 pm »
No you misunderstand,  I like the volume of the new one. How do I get the older one louder like the new one?
Assuming you have swapped the two units and made sure that the input levels of the sources are not involved, you can contact Bryston to have the earlier device's gain raised. This sort of adjustment is routine because of so many headphones with greatly varying characteristics on the market. There will be some people, me included, who end up with a very high output level with only a tiny rotation of the volume knob, making it difficult to set the desired level accurately. In these cases, the gain is decreased with some minor internal change.

Grit

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1243 on: 27 Aug 2020, 05:49 pm »
Had that exact problem (Audeze headphones). Sent it in and had it adjusted. Works great now.

schugh

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1244 on: 11 Sep 2020, 08:18 pm »
Hi Samjay!

You might try removing the pot from the shaft (there is only one screw that holds it in place) and use a very small amount of WD-40 or some specialized agent for electrical contact rejuvenation. I found this to be the case with my BHA-1 which is a very early S/N unit. Lots of things can contribute to this and in my case, it is extremely high humditiy where I live. 97% relative humidity at +40C can't be a good thing for anyone or anything, can it?

Most conventional volume potentiometers are like this and they require frequent use and in some cases, periodic maintenance.

Cheers,
Antun

Thanks! I can't get the volume knob off. I can't even open the cover. Looks like they are those Torx screws. I have those screwdrivers. I tried a T7 and T9 but they are so tight. I can't even budge them.
Afraid I'm going to strip the screws.

schugh

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1245 on: 13 Sep 2020, 01:02 am »
Well, I got a better screw driver and did manage to take the cover off. But I don't see how to take the volume knob off.
I know the knob has a hole in it but I can't tell what fits in it and if you can loosen it that way.

-- Sanjay

Jozsef

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1246 on: 13 Sep 2020, 04:57 am »
WD-40 is essentially a cleaner, petroleum distillate to be precise, I believe. It has no significant lubrication properties and should used only on pots you don't care about simply because it was not made to avoid damaging resistor rings. You would be gambling, or experimenting, if you want to put it that way. Don't do it. Bryston will help you so start there.

Grit

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1247 on: 16 Sep 2020, 06:02 pm »
WD-40 is essentially a cleaner, petroleum distillate to be precise, I believe. It has no significant lubrication properties and should used only on pots you don't care about simply because it was not made to avoid damaging resistor rings. You would be gambling, or experimenting, if you want to put it that way. Don't do it. Bryston will help you so start there.
I've been told WD stands for Water Displacement (formula 40). Not sure if that's true or not, but it makes sense.

And agreed. Please send your equip to Bryston. They have all the equipment and expertise to guarntee you get it back as good as new.

- Garrett

Jozsef

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1248 on: 17 Sep 2020, 04:12 am »
I've been told WD stands for Water Displacement (formula 40). Not sure if that's true or not, but it makes sense.

And agreed. Please send your equip to Bryston. They have all the equipment and expertise to guarntee you get it back as good as new.

- Garrett
That is correct and the 40 is a reference to the number of formulas that they tried before finding the one that had the characteristics they wanted. It's a good product for some types of cleaning but being petroleum distillate, it is somewhat toxic to inhale and does harm rubber after a while, contrary to what the maker claims.

R. Daneel

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1249 on: 17 Sep 2020, 01:01 pm »
Fellas, isn't there a special WD formulation for electrical contacts? This is the one I was referring to in my original post.

Unless there's physical damage to the resistive taper inside the pot, a slightly crackling pot is hardly a reason to send an amplifier in. Turnaround will take weeks and with the current state of affairs, postage might not be risk-free either.

Speaking of volume pot in the BHA-1, is it a Noble or an Alps? My amp's S/N is in the 300 range and it was among the first ones to have preamp outputs.

Cheers,
Antun

schugh

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1250 on: 17 Sep 2020, 06:08 pm »
I've got an RMA# from Mike.
It's not user serviceable after I asked him if I could do something to get rid of the noise volume.
I don't like a crackly volume knob.

-- Sanjay

mav52

Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1251 on: 15 Oct 2020, 11:50 am »
Got a question. I read this statement on Moon-Audio regarding the BHA-1  "The Bryston headphone amp is not a 'true' balanced headphone amp even though it has balanced inputs and balanced outputs. They use operational amplifiers by changing the input to single ended, installing a single-ended circuit and changing it to a balanced output for the headphone jack."

James is this true.   ??   

James Tanner

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Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1252 on: 15 Oct 2020, 12:16 pm »
Got a question. I read this statement on Moon-Audio regarding the BHA-1  "The Bryston headphone amp is not a 'true' balanced headphone amp even though it has balanced inputs and balanced outputs. They use operational amplifiers by changing the input to single ended, installing a single-ended circuit and changing it to a balanced output for the headphone jack."

James is this true.   ??

The inputs and the outputs are a fully differential balanced design (to eliminate noise)  but the signal path through the preamplifier is single ended.

james

mav52

Re: BRYSTON BHA-1 HEADPHONE AMPLIFIER
« Reply #1253 on: 15 Oct 2020, 01:02 pm »
The inputs and the outputs are a fully differential balanced design (to eliminate noise)  but the signal path through the preamplifier is single ended.

james

Thank you James for the clarification.   I know I enjoy mine.