[MDR30]

Thanks Greg. 


Mylar it is.   So the kapton is the bass heavy version? 

Just to avoid confusion, the colour refers to the plastic, not the metal traces, so the driver on the photo is the kapton version.

 

[DefectiveAudioComponent]

 
Well, this is not the case.  Definitely, there is no strong bass... just weak weak bass...  I'd say the AKG Q701 drivers produce very strong bass compared to PMB 80.

 
I'd say there is a very good chance that the bass is all there still, just cancelled out by the backwave at the moment. The combination of deep powerful bass with airy highs is one of the finest characteristics of the PMB series - but it takes some experimentation to bring it out.

 

[MuZo2]

   
 The combination of deep powerful bass with airy highs is one of the finest characteristics of the PMB series

Fully agree.

 

[zeroduke]

   
I'd say there is a very good chance that the bass is all there still, just cancelled out by the backwave at the moment. The combination of deep powerful bass with airy highs is one of the finest characteristics of the PMB series - but it takes some experimentation to bring it out.

Well, that's good news... I was thinking this one was a defective unit. But I have to find the bass.

 

[GREQ]

I 'found the bass' when I took the naked drivers out of U70 and held them up ONTO my ears.
Find a way to keep them there comfortably and you'll probably win some sort of headphone nobel prize equivalent for sure.
 
Apparently these are not as good as the higher end PMB drivers but I experienced the same effect as others report.
 
Replacing the old white earpads with pleathers is also a good place to start.

 

[zeroduke]

  I 'found the bass' when I took the naked drivers out of U70 and held them up ONTO my ears.
Find a way to keep them there comfortably and you'll probably win some sort of headphone nobel prize equivalent for sure.
 
Apparently these are not as good as the higher end PMB drivers but I experienced the same effect as others report.
 
Replacing the old white earpads with pleathers is also a good place to start. 

OK.  Thanks.

 

[DefectiveAudioComponent]

I 'found the bass' when I took the naked drivers out of U70 and held them up ONTO my ears.
Find a way to keep them there comfortably and you'll probably win some sort of headphone nobel prize equivalent for sure.

I do not expect a nobel prize, but that's the modification I did to my RT-10, and it does indeed sound spectacularly good.

 

[DefectiveAudioComponent]

... in case anyone else would like to try it out - the key is as mentioned to hold the drivers comfortable onto the ears. This modification goes against all conventional modification rules - it does not rely on sealing the driver to the baffle. Instead, it relies on having an exceptionally short distance between the driver and the ear, thus avoiding bass cancellation from the back wave.

The solution is really very simple, just mount the driver on the outside of the baffle. Then place (deep enough) circumaural pads on top. Use e.g. blutack to position the driver comfortably.

(The pads ned to have a stretchy thin protector fabric toward the baffle, to protect the driver, and to make it all look perfectly normal.)

 

[zeroduke]

... in case anyone else would like to try it out - the key is as mentioned to hold the drivers comfortable onto the ears. This modification goes against all conventional modification rules - it does not rely on sealing the driver to the baffle. Instead, it relies on having an exceptionally short distance between the driver and the ear, thus avoiding bass cancellation from the back wave.

The solution is really very simple, just mount the driver on the outside of the baffle. Then place (deep enough) circumaural pads on top. Use e.g. blutack to position the driver comfortably.

Thanks. I understand. But doing this involves a radical mod to the unit, doesn't it?  I would prefer to keep the original look too.  For instance, this unit has white pads (original as the PMB80 was NOS, sealed box) and they are quite thin.    But the box shows a pleather pad. 
GREQ says that using pleather could be a way to start.  German Maestro sells pleather pads and I know they go perfectly well on PMB80. Or is the modification you wrote about the only way the PMB80 would show more bass? 
 

 

[DefectiveAudioComponent]

Thanks. I understand. But doing this involves a radical mod to the unit, doesn't it?  I would prefer to keep the original look too.  For instance, this unit has white pads (original as the PMB80 was NOS, sealed box) and they are quite thin.    But the box shows a pleather pad. 
GREQ says that using pleather could be a way to start.  German Maestro sells pleather pads and I know they go perfectly well on PMB80. Or is the modification you wrote about the only way the PMB80 would show more bass? 

Yes, the white pads should have been black, the pleather has been destroyed on them, this always happens ( I picked up a NOS PMB-6, with intact pleather pads, but a short while after I tried them on, the pleather flaked off - it does not survive skin contact). Replacing them with stock German Maestro pads will probably (I have not tested it) restore them close to the original, both in looks and in sound. (However, I have not been able to get the bass restored (without loosing the highs) with pads similar to the stock pads - but perhaps the German Maestro stock pads are different, somehow...)

This is my pair (similar to the PMB-80), with thicker pads. (I sold my PMB-80, unfortunately for me, before I figured out how to fix the sound)


The modification is reversible as long as you use something removable like blu-tack to hold the driver outside the baffle.
(remember, there is no need to seal the baffle, and no need to close the cups, you can keep the baffle fully vented (there is an opening, perhaps 2mm wide around the driver), and the back fully open, like it is stock.)

There are so far four known versions of the PMB-80 ( including those with other brands, and slightly different headsets).

 

[szerecsen]

I now have both RP18 versions, too. They are both untouched, and indeed, completely different. To be honest,  I was not expecting this much of a difference between the two. Yet, I would not tell either one to be superior to the other. They are just different as chalk and cheese. 

 

[BucketInABucket]

Selling my YH-1 if anyone is interested 

 

[leeperry]

I know that the Wharfedale ID1 manual advises to tap it directly off speakers terminals and that Hifiman sell a box to do exactly that but is anyone seriously used to do this?
 
I mean most vintage orthos take extreme gain to coax serious bass and I just scored several full discrete stereo AVR's so I though I'd give it a shot but I'd rather not toast my orthos huh, IIRC Fostex talk about a 3W max wattage on their T50RP so I would guess that all should be well?
One of them is from Onkyo and claims to run a full balanced internal design, sounds like a plan

 
I'm also used to only plug my phones once the headamp is on and unplug them before turning them off, this would be a no-go with the speakers kludge if I don't bother building an Hifiman-like box but I think some of them got anti-pop relays so that should be fine.
 
Some boutique manufacturers claim that their headamps are so beefy that they could drive speakers, the hell with it then ^^

 

[Hutnicks]

  I know that the Wharfedale ID1 manual advises to tap it directly off speakers terminals and that Hifiman sell a box to do exactly that but is anyone seriously used to do this?
 
I mean most vintage orthos take extreme gain to coax serious bass and I just scored several full discrete stereo AVR's so I though I'd give it a shot but I'd rather not toast my orthos huh, IIRC Fostex talk about a 3W max wattage on their T50RP so I would guess that all should be well?
One of them is from Onkyo and claims to run a full balanced internal design, sounds like a plan

 
I'm also used to only plug my phones once the headamp is on and unplug them before turning them off, this would be a no-go with the speakers kludge if I don't bother building an Hifiman-like box but I think some of them got anti-pop relays so that should be fine.
 
Some boutique manufacturers claim that their headamps are so beefy that they could drive speakers, the hell with it then ^^

There is an entire thread on here about driving Headphones with a speaker amp. Most would be surprised at results you can get and really question the wisdom of a home headphone amp at all after using a decent set up.
 
The short version. If the outputs on the amp have a common ground DO NOT DO IT you will cause a dead short with your HP's becoming little more than a fuse. If it is not a common ground (you can test this with a meter. Connect the meter to - on both the left and right channels WITH THE AMP OFF and if there is continuity it is a common ground, if there is no continuity it is not) you can connect headphones the same way you would connect a speaker. Dual cables, one for each channel to the driver. Important to have the volume set to zero and SLOWLY turn it up to power the phones. Noise floor may be an issue and the thread has myriad resistor network schemes for reducing that.
 
http://www.head-fi.org/t/649107/speaker-amps-for-headphones        The posts from Armageis are usually accurate and informative.

 

[leeperry]

Very nice thanks! I did find some posts explaining clearly that I cannot go TRS due to the shared groud but that's no issue, my only problem is that the Onkyo uses digital volume control and in case of a power outage for instance this might lead to catastrophic consequences huh........anyway, it would appear that some AVR's use a crappy opamp on their HO and others do it the right way and actually connect the phone to the speakers amp using the right filtering circuit in between so we shall see....only one way to find out, maybe I'll give a shot to the speakers out on the Pioneer with the analog knob for fun but first I'll try a cheapo dynamic