Fostex T50RP Incremental Mods and Measurements

[bluemonkeyflyer]

I'm diggin' my new Project Sunrise II Amp!
 
Upon the recommendation of geetarman49 and chinook9, I recently bought a Project Sunrise II tube-hybrid amp from 'garage1217 <dot> com'.  Setting bias is so easy and a DMM is not necessary. All you do is turn a couple of screws while watching 2 LEDs. It's compatible with over 80 tubes - both 6 and 12 volt tubes. Output impedance is adjustable for 5 and 68 ohms via 2 jumpers accessible on the sides. It has a laser cut clear acrylic (?) top so you can see all the components and the "light show." Three RGB LEDs under the tube are adjustable for any color you like. I have mine currently set for violet. The input caps can be bypassed, if desired.
 
What about the sound?!  Two words: Phenomenal Fidelity. The detail from bottom bass to top treble notes is excellent. The mids are creamy smooth and lush. Bottom Line: I like. Very much.
 
It sells for $199 in kit form or fully assembled with warranty for $249. I think it's a steal. I like it so much I bought 2 more I'm sending to my son and my brother. They are in for a sweet surprise and beautiful tunes.
 
EDIT: A friend from "across the pond" asked me how this amp sounds with my LCD2's.  Short answer: Excellent. Plenty of headroom. And, believe it or not, my DBV #3's sound almost as good as my LCD2's. IMO, YMMV, etc., just sayin'.
 
 

 
Project Sunrise II - Left side
 
 

 
Front
 
 

 
Right

 

[PhaedraCorruption]

I think I have taken my T50RPs apart more than 200 times now and it's starting to show. I'm especially upset that I lost the stock back white papers so I'm going to pick up 2 more of these cans.. and at 79.99, why not?

 

[kingoftown1]

Quote:

I'm diggin' my new Project Sunrise II Amp!
 
Upon the recommendation of geetarman49 and chinook9, I recently bought a Project Sunrise II tube-hybrid amp from 'garage <dot> com'.  Setting bias is so easy and a DMM is not necessary. All you do is turn a couple of screws while watching 2 LEDs. It's compatible with over 80 tubes - both 6 and 12 volt tubes. Output impedance is adjustable for 5 and 68 ohms via 2 jumpers accessible on the sides. It has a laser cut clear acrylic (?) top so you can see all the components and the "light show." Three RGB LEDs under the tube are adjustable for any color you like. I have mine currently set for violet. The input caps can be bypassed, if desired.
 
What about the sound?!  Two words: Phenomenal Fidelity. The detail from bottom bass to top treble notes is excellent. The mids are creamy smooth and lush. Bottom Line: I like. Very much.
 
It sells for $199 in kit form or fully assembled with warranty for $249. I think it's a steal. I like it so much I bought 2 more I'm sending to my son and my brother. They are in for a sweet surprise and beautiful tunes.
 
EDIT: A friend from "across the pond" asked me how this amp sounds with my LCD2's.  Short answer: Excellent. Plenty of headroom. And, believe it or not, my DBV #3's sound almost as good as my LCD2's. IMO, YMMV, etc., just sayin'.

I know this is venturing off-topic, but have you tested the PSII as a preamp yet and have any comments on its performance in that aspect?

 

[bluemonkeyflyer]

I know this is venturing off-topic, but have you tested the PSII as a preamp yet and have any comments on its performance in that aspect?

KOT,

I have not tried it as a pre-amp. I'm happy with my McIntosh MX-136 pre/pro but will likely give this a try over the weekend now that you mention it. It'll be interesting to see how a $250 "David" stands up to an $8k "Goliath."

 

[bluemonkeyflyer]

Quote:

I think I have taken my T50RPs apart more than 200 times now and it's starting to show. I'm especially upset that I lost the stock back white papers so I'm going to pick up 2 more of these cans.. and at 79.99, why not?

Then you are a "veteran" modder!  Have you tried the "Naked Driver" mod?
 
That's a real good price for T50RP's. The cheapest I've seen for months is $99 at Amazon.

 

[kingoftown1]

Quote:

KOT,
I have not tried it as a pre-amp. I'm happy with my McIntosh MX-136 pre/pro but will likely give this a try over the weekend now that you mention it. It'll be interesting to see how a $250 "David" stands up to an $8k "Goliath."

Thanks, I couldn't ask for more

 

[chrislangley4253]

man, that's a good looking amp. I kinda just want one for that reason alone.

 

[bluemonkeyflyer]

Quote:

man, that's a good looking amp. I kinda just want one for that reason alone.

 
What's really great about it is not just its "Kool Factor" but its beautiful sound.  And, the price is Right!

 

[Dgiant]

What mod should I do to increase the bass a bit. It seems very lacking compared to my denon d5000s.

Ps. I have already done the baffling with newplast.

 

[PhaedraCorruption]

Quote:

Then you are a "veteran" modder!  Have you tried the "Naked Driver" mod?
 
That's a real good price for T50RP's. The cheapest I've seen for months is $99 at Amazon.

Thanks!
 
Naked Driver? Sounds kinky. 
 
Is this the one with 20x25mm of magazine paper under 2 layers of thick craft felt? 
 
If so, yes. That is what I'm running right now and it sounds decent.
 
And it looks like i was mistaken with the price of the cans. I assumed they would be around $80 because I bought my pair for $74.95. Looks like they are indeed up to $100 now. Still worth it without a shadow of a doubt though. 
 
I used a slightly different method from yours in my measurements. I build a head dummy and crammed one of these in it http://www.amazon.com/Behringer-ECM8000-Ultra-Linear-Measurement-Microphone/dp/B000HT4RSA
 
I'll post my exact setup when I have time. I'm currently in the process of looking for some of the Riteaid cotton you mentioned, I'm in Canada and I can't seem to find it in any of the stores here...
 
Tomorrow I'll have a pair of LCD-2s to measure and hopefully with that I will be able to compare my T50RPs with something of higher caliber. 

 

[bluemonkeyflyer]

Quote:

Thanks!
 
Naked Driver? Sounds kinky. 
 
Is this the one with 20x25mm of magazine paper under 2 layers of thick craft felt? 
 
If so, yes. That is what I'm running right now and it sounds decent.
 
And it looks like i was mistaken with the price of the cans. I assumed they would be around $80 because I bought my pair for $74.95. Looks like they are indeed up to $100 now. Still worth it without a shadow of a doubt though. 
 
I used a slightly different method from yours in my measurements. I build a head dummy and crammed one of these in it http://www.amazon.com/Behringer-ECM8000-Ultra-Linear-Measurement-Microphone/dp/B000HT4RSA
 
I'll post my exact setup when I have time. I'm currently in the process of looking for some of the Riteaid cotton you mentioned, I'm in Canada and I can't seem to find it in any of the stores here...
 
Tomorrow I'll have a pair of LCD-2s to measure and hopefully with that I will be able to compare my T50RPs with something of higher caliber. 

 
I bought a calibrated Galaxy CM-140 SPL meter and a styrofoam head. I removed part of the back and drilled a hole for the SPL probe. I tried some measurements with it but found it to be unreliable. I think the problem with it was that it was almost impossible to position the headphones in the same place. I have an idea to correct this problem but have not tried it, yet.
 
Yes, that's the "Naked Driver" mod I mentioned. It sounds real good and very close to DBV #3 with the stock white driver material intact. What's key is getting the cotton just right.  If you use dense, matted cotton like Rite Aid "First Aid Rolled Cotton," US Absorbent Cotton Roll," and "London Drugs Absorbent Cotton" without first "preparing" it, sound quality suffers. Properly preparing these types of cotton products before installing is very important, IME/IMO, for favorable results....YMMV, etc. 

 

[PhaedraCorruption]

Quote:

 
I bought a calibrated Galaxy CM-140 SPL meter and a styrofoam head. I removed part of the back and drilled a hole for the SPL probe. I tried some measurements with it but found it to be unreliable. I think the problem with it was that it was almost impossible to position the headphones in the same place. I have an idea to correct this problem but have not tried it, yet.
 
Yes, that's the "Naked Driver" mod I mentioned. It sounds real good and very close to DBV #3 with the stock white driver material intact. What's key is getting the cotton just right.  If you use dense, matted cotton like Rite Aid "First Aid Rolled Cotton," US Absorbent Cotton Roll," and "London Drugs Absorbent Cotton" without first "preparing" it, sound quality suffers. Properly preparing these types of cotton products before installing is very important, IME/IMO, for favorable results....YMMV, etc. 

I'll get some pictures of the mic setup I have later.
 
I'm currently using a similar setup to DBV #3, except I'm using polyfill instead of cotton and Owens Corning fiberglass and I'm using the naked driver mod with magazine paper. 
 
I'm just not getting enough bass. I tried sealing the vent up all the way and still nothing. Since I'm using the naked driver mod, I'm not sure how I would go about perhaps punching some holes in the felt. I have 2 layers of the thick craft felt over the driver, with the magazine paper sandwiched in between.

 

[MuZo2]

What pads are you using ? may be you over damped them with polyfill and Corning fiberglass, try  reducing the polyfill and also try shure pads. 

 

[bluemonkeyflyer]

Quote:

I'll get some pictures of the mic setup I have later.
 
I'm currently using a similar setup to DBV #3, except I'm using polyfill instead of cotton and Owens Corning fiberglass and I'm using the naked driver mod with magazine paper. 
 
I'm just not getting enough bass. I tried sealing the vent up all the way and still nothing. Since I'm using the naked driver mod, I'm not sure how I would go about perhaps punching some holes in the felt. I have 2 layers of the thick craft felt over the driver, with the magazine paper sandwiched in between.

 
Which vent(s) did you seal?
 
I've tried polyfill - a small amount to over-stuffed with and without cotton and/or fiberglass. I could never get it to work for me but YMMV.
 
Did you try the paper over the back of the driver and under both layers of stiff felt?  What size paper?

 

[bluemonkeyflyer]

Update: I edited and added additional information and pictures to "Simplified and Consolidated Tutorial/Pictorial for DBV #3." Go to Post #1 of this thread and scroll down past Graph #55. Included are photos and step-by-step instructions required for preparing Rite Aid "First Aid Rolled Cotton" so it will perform like Rite Aid "Natural Absorbent Cotton." 
 
I hope this helps.