[AutumnCrown]

Hi all,

I suffered an acoustic trauma last year which gave me tinnitus, and am bothered by the possibility of my headphones blasting music in my ears by accident. I know this is not an entirely rationale thing to worry about, but I think it would help me recover from this event to have an amp which could not physically blast an HD800 or Verite louder than about 110 dB even at 0 dB.Right now I am using the iDSD micro on eco, which is fine except I don't entirely trust the gain switch.

Also wondering if there are certain amp topologies or types which are less likely to fail in such a way that could result in an extra loud signal.

I know I can use calculators to figure this stuff out, but I am wondering if anyone has any particular amps in mind which might be good for this use case. I will be listening with ZMF verite and HD800 S.

 

[gimmeheadroom]

I think it's really the opposite. I haven't heard the Verite, but the 800/800S needs healthy power like any 300 ohm Sennheiser and is already analytical and cold. If you have enough power at low volumes you will have a fuller sound and enjoy listening at lower levels. Low power amps that can't cut it cause people to listen at levels that are too high, to compensate for the lack of good sound at low listening volumes.

I would recomment a tube OTL amp for these cans. They deliver plenty of voltage and should warm up the sound. Just get in the practice of turning the volume down before you plug in the headphones and before you unplug them.

Good luck with the health problems. I feel your pain, I was at an event where the sound guy was irresponsible and I have tinnitus ever since.

 

[AutumnCrown]

I think it's really the opposite. I haven't heard the Verite, but the 800/800S needs healthy power like any 300 ohm Sennheiser and is already analytical and cold. If you have enough power at low volumes you will have a fuller sound and enjoy listening at lower levels. Low power amps that can't cut it cause people to listen at levels that are too high, to compensate for the lack of good sound at low listening volumes.

I would recomment a tube OTL amp for these cans. They deliver plenty of voltage and should warm up the sound. Just get in the practice of turning the volume down before you plug in the headphones and before you unplug them.

Good luck with the health problems. I feel your pain, I was at an event where the sound guy was irresponsible and I have tinnitus ever since.

I‘m trying to have both good SQ and low max volume though.

 

[tomb]

I would suggest an output-transformer equipped tube amp. Pick one using the a tube family that allows you to roll in a low-gain tube, such as the 12A*7 family (12AU7 will have lowest gain). Transformers inherently protect against DC, needing no relay-delay. They are also self-limiting in power and high-frequency response. Some start dropping off at 15kHz. Although the response is not down very much at 20kHz, it's still in the right direction to protect the ears.

The downside is cost. Musical tone and lack of harshness is present with all of them, but greater detail means more exotic materials and cost.

Edit: Removed a much more detailed response that was a massive overkill.

 

[E8ArmyDiver]

I have seen amps with adjustable gain that would allow you to turn down the absolute maximum volume..I can't recall which ones have this so you'll have to flex your Google fu...Good luck..

 

[AutumnCrown]

I would suggest an output-transformer equipped tube amp. Pick one using the a tube family that allows you to roll in a low-gain tube, such as the 12A*7 family (12AU7 will have lowest gain). Transformers inherently protect against DC, needing no relay-delay. They are also self-limiting in power and high-frequency response. Some start dropping off at 15kHz. Although the response is not down very much at 20kHz, it's still in the right direction to protect the ears.

The downside is cost. Musical tone and lack of harshness is present with all of them, but greater detail means more exotic materials and cost.

Edit: Removed a much more detailed response that was a massive overkill.

Awesome, this is exactly the kind of information I was looking for. Thank you! Kind of curious about your overkill answer now though Can you give me an example of ones of these amps under 1k?

 

[Joe Garfield]

What about a good, powerful amp with a modified volume pot, added resistors, or an external volume limiter?

 

[tomb]

Awesome, this is exactly the kind of information I was looking for. Thank you! Kind of curious about your overkill answer now though Can you give me an example of ones of these amps under 1k?

The better ones will be more than $1K. You might look for a used ECP Audio Torpedo III (T3) or a Mapletree Ear headphone amplifier. You should be able to get either of those for less than $1K, although that might be pushing it for the T3.

The primary difference in dealing with output transformer equipped tube amps is in detail. Greater detail results in using more exotic materials in the output transformers. That costs more. Probably lowest on the detail/quality range of OTs is Hammond (used in the Mapletree Ear), then Edcor (used in some of Pete Millett's Apex designs), Cinemag nickel-core (used in the T3), Lundahl special steel (used in the ECP Audio T4), Lundahl amorphous core (I believe used in Pete Millett's Apex Pinnacle Ultra). Then there's maybe Electra-Print silver wire OTs, but I haven't had any experience with those and he may just be riding his reputation of exclusivity and high-cost. Certainly, the Lundahl amorphous cores are the finest OTs I've ever heard, but they are enormously expensive and huge. You're probably talking about a $5K amp, minimum, for amorphous core OTs. Pete Millett's Pinnacle Ultra is currently on sale for $9K at TTVJ.

Unlike what many experience with tube headphone amplifiers - hum, all of those mentioned above will have a solid-black background with no discernable (or barely measurable) noise.

 

[marcgii]

I use my 800S with the Hagerman Tuba exclusively. It's probably not the best tube amp under 1k in terms of synergy. But I think it's great. It's also transformer coupled. So it's good for low impedance headphones as well unlike OTL amps.

 

[AutumnCrown]

The better ones will be more than $1K. You might look for a used ECP Audio Torpedo III (T3) or a Mapletree Ear headphone amplifier. You should be able to get either of those for less than $1K, although that might be pushing it for the T3.

The primary difference in dealing with output transformer equipped tube amps is in detail. Greater detail results in using more exotic materials in the output transformers. That costs more. Probably lowest on the detail/quality range of OTs is Hammond (used in the Mapletree Ear), then Edcor (used in some of Pete Millett's Apex designs), Cinemag nickel-core (used in the T3), Lundahl special steel (used in the ECP Audio T4), Lundahl amorphous core (I believe used in Pete Millett's Apex Pinnacle Ultra). Then there's maybe Electra-Print silver wire OTs, but I haven't had any experience with those and he may just be riding his reputation of exclusivity and high-cost. Certainly, the Lundahl amorphous cores are the finest OTs I've ever heard, but they are enormously expensive and huge. You're probably talking about a $5K amp, minimum, for amorphous core OTs. Pete Millett's Pinnacle Ultra is currently on sale for $9K at TTVJ.

Unlike what many experience with tube headphone amplifiers - hum, all of those mentioned above will have a solid-black background with no discernable (or barely measurable) noise.

I am looking the ECP T4. http://beezar.com/pho-bzr/catalog/product_info.php?products_id=193

Looks like it has an XLR connector which has been ground to make it even safer in case the transformer failed. Do you know if another output transformer in a 1/4 inch single ended configuration would be similarly safe? 1/4 inch normally has a negative, positive, and ground - so that should function the same as this special grounded XLR right? Thank you very much for all of your help!

 

[tomb]

I am looking the ECP T4. http://beezar.com/pho-bzr/catalog/product_info.php?products_id=193

Looks like it has an XLR connector which has been ground to make it even safer in case the transformer failed. Do you know if another output transformer in a 1/4 inch single ended configuration would be similarly safe? 1/4 inch normally has a negative, positive, and ground - so that should function the same as this special grounded XLR right? Thank you very much for all of your help!

Yes, of course. The XLR jack in the T4 is used for convenience and robustness, but you can easily use an XLR-to-TRS adapter. As you stated, the T4 is fully differential, but the outputs are grounded at the transformers back into single-ended for safety from the voltage behind (250+V).

There is a lot of debate about this with differential/balanced, etc., but we believe the three primary benefits people usually list for differential circuits are either enjoyed already with the T4 configuration or don't apply with tubes:

• Differential circuits cancel out common mode distortion. (This is achieved in a differential amplifier circuit whether the inputs/outputs are single-ended or not.)
• Differential circuits increase the voltage swing, for substantial improvement using high-impedance headphones. (This is addressing an inherent weakness with solid-state: limited voltage availability. With true high-voltage tube circuits, you're already dealing with hundreds of volts. Ample voltage swing is not an issue.)
• Differential circuits automatically increase the voltage slew rate. (Admittedly, this is an advantage - although not really, if you subscribe to NwAvGuy - I don't. Use of vacuum tubes sets the slew rate, anyway.)

The T4 achieves the greatest benefits available for tube-based differential amplifiers, even if the inputs/outputs are single-ended.

Conversely, there are some who argue that "Balanced" is different than "Differential." To 99% of most head-fiers, "Balanced" means "Differential." However, there are some companies that manufacture headphone amps claiming "Balanced" operation. In these cases, the headphone amplifier circuit is simple single-ended throughout its internal circuitry, but its inputs/outputs are compatible with a "Differential" connection. So, they claim their amp offers "Balanced" operation, even though it has no "Differential" circuitry.

The T4 is just the opposite. We claim no "Balanced" connection compatibility, but the circuit inside the amplifier is fully Differential.