ASL MG Head vs. ASL AQ 1005 DT-I

[Chad]

I'm interested in purchasing the Antique Sound
Lab MG Head Tube Amp and would like to know if their
AQ 1005 DT-I would perform much better than MG Head in
terms of the added cost. I am planning to use it with
the Grado RS-1 for classical music. Thank you!

 

[joelongwood]

I have the MG Head and RS-1, and to my ears, the combo is not too good. Some other people here also do not feel the MG Head matches up well with Grados. For the money, I'd recommend the RA-1..........an excellent match for the RS-1. Hope this helps.
BTW, welcome to Head-Fi, Chad!

 

[chych]

Ehhh the 1005DT is an 8watt/channel power amplifier while the MG Head is a 150mW/channel headamp/pseudo-preamp, I wouldn't use the 1005 unless you have AKG K1000s or you plan on destroying your Grados

Actually I wouldn't use the MG Head at all on Grados, like joelongwood stated.

 

[Joe Lau]

Quote:

Originally posted by chych Ehhh the 1005DT is an 8watt/channel power amplifier while the MG Head is a 150mW/channel headamp/pseudo-preamp, I wouldn't use the 1005 unless you have AKG K1000s or you plan on destroying your Grados Actually I wouldn't use the MG Head at all on Grados, like joelongwood stated.

It will change your mind ! MG-Head OTL will comming soon. It can match Grado 32 Ohm Headphone with better sound comapre with Old MG-Head. Actaully Old MG-Head are very easy to convert to MG-Head OTL. Just connect a 100/160V to Plate of 6BQ5 and Disconnect the Feed back. It become a OTL mode Headphone amps with better bass, better sound stage....

AQ1005DT for Grado RS-1. Yes ! I also not suggest to use it on RS1. You will heard too much Hum due to too high efficient and AQ1005DT have too much gain if you use it on RS-1. It is so good for AKG1000 but not for RS1. I had test simulair configue to test how it work on high efficient headphone. It is not good except modify it to lower gain or connect to our New Headphone Converter. UHC-Signature. It have a step down transformers to step down the output voltage to less than 2V when you connect to 32 Ohm Headphone.

 

[jim]

Joe, do you think you could post some more detailed instructions on the MG Head modification? Ideally, I'd like to be able to switch between OTL and the transformers using the impedence switch that's already there, if that's possible. What exactly do I connect the capacitor to? If you don't mind, please be as specific as possible, because I don't have much electronics experience! Thanks!

 

[Joe Lau]

Quote:

Originally posted by jim Joe, do you think you could post some more detailed instructions on the MG Head modification? Ideally, I'd like to be able to switch between OTL and the transformers using the impedence switch that's already there, if that's possible. What exactly do I connect the capacitor to? If you don't mind, please be as specific as possible, because I don't have much electronics experience! Thanks!

It is so simple - Connect a 100/160V Positive to Plate of 6BQ5 , Connect the negative to Headphone. (Headphone - 1 wire to negative of 100/160V and other end to ground).

Use switch to control OTL and Transformers out -

Connect Headphone to Mid point of Switch , OTL mode out from 100/160V connect to one side of Switch , Transformers secondary connect to other side of switch. I suggest to add a switch to switch off nfb when working in OTL mode. Or 1 Jack for OTL and other Jack for transformers out. It only need a switch to disconnect the nfb when working in OTL mode.
New MG-HeadDT - It use 1/4" Jack x 2 as output , 1 for OTL and other for transformers out. Switch is become a Nfb control only. It will have a Air shipment from HK to Canada within this weeks. I have send a Sample unit to Acidware.com to test it. He tell me can drive Grado 32 Ohm Headphone in good condition.

Caution : Don't Change mode or unplug Jack in operation.
It will generated POp when switching.

 

[Hardhead]

You have to love it when the company's head guy gets on line and suggests that his amp isn't the most compatible for a particular headphone and suggests the appropriate modifications so that everyone can modify their "old" Head DT to the OLT version which hasn't even been released yet!!!!

Another reason to buy the ASL Head. BTW I was able to listen to both the Wheatfield HA-2 and the Head DT at the HeadRoom meeting and thought that the Wheatfield had a slight advantage (at about twice the price) especially in the bass area. However, other Head-Fiers recommend tube rolling to enhance the Head's bass response.

Joe, how would you compare the sound of the upcoming Head OLT to the current version? Any suggestions for alternative tubes for the current version? You've mentioned some Chinese tubes in another posting.

Thanks for listening to us stereo people!

 

[chych]

I think some of us need it a little simpler...

>It is so simple - Connect a 100/160V Positive to Plate of 6BQ5, Connect the negative to Headphone.

1) Whats a 100/160V and te Positive?
2) Whats the plate of the 6BQ5?
3) Whats the negative to headphone? I am guessing this is the actual thing on the headphone jack?

It'll go on

 

[Joe Lau]

Quote:

Originally posted by chych I think some of us need it a little simpler... >It is so simple - Connect a 100/160V Positive to Plate of 6BQ5, Connect the negative to Headphone. 1) Whats a 100/160V and te Positive? 2) Whats the plate of the 6BQ5? 3) Whats the negative to headphone? I am guessing this is the actual thing on the headphone jack? It'll go on

1. 100/160V - It is a Additional E-cap with Polar , So it have positive and negatuve.
2. Plate of 6BQ5 - It is a Pins of 6BQ5 tube.
3. Negative Pole of 100/160V

It is not for user don't have electrical experience due to high voltage inside.

 

[mackay maus]

Hi Chad;

I have the MG Head with stock tubes. My RS-1 sounds okay, but not as good as the Senn 600. I listen to mainly jazz and classical, with a healthy dose of rock.

To my ear, the RS-1 sounds better via the RA-1 amp. I know there are mixed reviews on the RA-1, but I like the sound, and the unit is drop dead beautiful. It's a pleasure just to sit there and look at it while I work.

In short, the MG Head/600 combo is great, as is the RS-1/RA-1. You can't go wrong with either set up. I tend to reserve the RS-1/RA-1 for rock and love the sound.

For the cost of the AQ 1005 DT, couldn't you buy and MG Head and an RA-1?

To further cloud the waters, if I could have only one set up, it would be my cosmic/ ER4s.

M

 

[Budgie]

Clarification:
100/160v = 100mfd/ 160vdc electrolytic capacitor

The positive lead of the capacitor goes to the plate of the 6BQ5 tubes. (One tube is the left channel, one tube is the right channel, so you will need two of these caps).

The negative lead of the caps connects to the headphone jack positive terminals. The headphone jack ground connection remains as is.

Disconnect the feedback circuits for the two channels.

(the capacitor values are the minimum you would want to use. you may use a larger value, but not a smaller value.)

DO NOT attempt this modification without the knowledge of how do do it safely. There are dangerous voltages inside the ampifier and doing the mod incorrectly could dmage the equipment and anyone who tries to use it.

 

[Kim Hardee]

I think I may have bad news for those of you who are hoping that the new MG Head OTL will work well with Grado phones. The 100mfd output capacitor will result in a bass rolloff at 50Hz if driving 32 ohm Grado headphones (do the math). This capacitor would have to be 250mfd to provide rolloff at 20Hz.

I called the distributor (Divergent Technologies) and they told me the new OTL amp will only work well with Grado phones when they are connected to the transformer output (non-OTL). I ordered the OTL amp because I have Sennheiser HD-600s.

I would like to know if the transformer output on the OTL amp is wired for low impedance or high impedance and if it is changeable by rewiring. If the same transformers are used as in the old amp, then this should be possible.

Maybe I'm missing something???

 

[Joe Lau]

Quote:

Originally posted by Kim Hardee I think I may have bad news for those of you who are hoping that the new MG Head OTL will work well with Grado phones. The 100mfd output capacitor will result in a bass rolloff at 50Hz if driving 32 ohm Grado headphones (do the math). This capacitor would have to be 250mfd to provide rolloff at 20Hz. I called the distributor (Divergent Technologies) and they told me the new OTL amp will only work well with Grado phones when they are connected to the transformer output (non-OTL). I ordered the OTL amp because I have Sennheiser HD-600s. I would like to know if the transformer output on the OTL amp is wired for low impedance or high impedance and if it is changeable by rewiring. If the same transformers are used as in the old amp, then this should be possible. Maybe I'm missing something???

It work Fine on OTL mode with Grado 32 Ohm - Yes ! Most Capacitor will get better base but I had test it is no problem when use 100Mfd/160V to get good enough for good bass.
It -3db point at 25 Hz not 50Hz when use 100Mfd. Whwn use 250Mfd will down to 10Hz but I think it is no need for Headphone amps.

 

[Kim Hardee]

I don't want to beat this bass rolloff issue to death but.....

I believe the equation for calculating the 3db down point is 1/(2XpiXRXC).

Therefore, the frquency response for R=32 and C=100mfd is 50Hz not 25Hz. This means the frquency response will begin rolling off at 100Hz and be 3db down at 50Hz. I think there would almost certainly be a noticeable loss of bass when listening to music with a lot of low bass content with Grado headphones if they are connected to the OTL ouput of this amp.
In general I believe the impedance of Grado phones is too low to work well with all-tube amps. They really need solid state or hybrid tube-SS to work well.

 

[Joe Lau]

Quote:

Originally posted by Kim Hardee I don't want to beat this bass rolloff issue to death but..... I believe the equation for calculating the 3db down point is 1/(2XpiXRXC). Therefore, the frquency response for R=32 and C=100mfd is 50Hz not 25Hz. This means the frquency response will begin rolling off at 100Hz and be 3db down at 50Hz. I think there would almost certainly be a noticeable loss of bass when listening to music with a lot of low bass content with Grado headphones if they are connected to the OTL ouput of this amp. In general I believe the impedance of Grado phones is too low to work well with all-tube amps. They really need solid state or hybrid tube-SS to work well.

Keep you eyes open ! It will be in Canada very soon. I calculated with Tube Cad. It seem to be so close to my testing.