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OTL Tube amps and Grados. - Page 4

post #46 of 58
Maybe one of these adapters? APureSound - Where The Music Is Always Pure - APS Audio LLC.
post #47 of 58
Quote:
Originally Posted by BIG POPPA View Post
these look very nice,thanks.
post #48 of 58
In general, I agree that Grados are better off with something other than an OTL tube amp, however, there are exceptions, as has been pointed out. For example, the RSA Raptor does an excellent job with the RS1.
post #49 of 58
The SP amps have a 20 ohm output impedance. A little tube rolling and it sounds very good with RS-1 and K701s.
post #50 of 58
post #51 of 58
I looked the mapletree homepage and can't find any pricing information, are these are custom made?

I do plan to get a WA2 for my Mpro, k702 with ALO cable mod. And surely will try if the amp can eat my ED8.
post #52 of 58
The other issue with Grado's on OTL amp is you need a huge electrolytic cap on the output, doesn't matter if Single Power or Eddie Current made the amp there is no way around this one, unless buy 20 lb $2000 film output caps.
post #53 of 58
Quote:
Originally Posted by stocklaz View Post
I looked the mapletree homepage and can't find any pricing information, are these are custom made?

I do plan to get a WA2 for my Mpro, k702 with ALO cable mod. And surely will try if the amp can eat my ED8.
Scroll up to the top and click on the PRICES tube.

Welcome to Mapletree Audio Design
post #54 of 58
There's another issue with OTL amps and Grados that hasn't been mentioned yet.

Some OTL manufacturers claim a fairly low ouput impedance for their OTL. Maybe they're right.

But you have to consider how they managed to pull this trick with relatively high output impedance tubes.

The usual trick is to crank up the negative feedback in the circuit. I don't quibble about negative feedback - a little bit can help stabilize the circuit. The problem is when you go heavy-handed with the feedback to force down the output impedance. It's like the difference between a pinch of salt in your soup and a handful of salt.

If you want to hear the difference feedback makes, track down an amp that doesn't use feedback at a meet. They (in my opinion) sound a world apart from an amp loaded down with feedback. You can also fiddle with a Bijou. It actually has a feedback control where you can adjust it from no feedback to a handful. Try it and see what you like - most prefer no feedback or a light touch.

Excessive feedback will strangle the music. Unfortunately, feedback is cheap to implemwnt and lets a manufacturer make all sorts of claims about the headphones cheap OTL will drive. Feedback is a bit of an esoteric concept and most people don't understand it. The average buyer mostly looks at the price and tuberolling capability. They don't lookat how the circuit operates, the quality of components or the build quality.

This is why I don't like cheap tube amps. In addition to pulling tricks like excessive negative feedback, they often use the very cheapest power transformers, have marginal filtering in the power supply, and are builton a PCB instead of point-to-point which is better suited to tubes.

If you're looking for quality amplification on a budget, just get solid state. I'm a tubehead, but the modestly priced solid state amps are really good. The difference is that you don't have to pay for a high voltage power supply for chips and a PCB is just fine. You'll get great sound from chips. If you want tubes, make sure the amp is built right with name brand transformers and uses a good circuit. That costs money. But you're much better off with a modestly priced solid state amp than a tube amp where every corner has been cut and the circuit jimmied with tons of feedback to bolster a marketing claim.
post #55 of 58
Quote:
Originally Posted by Uncle Erik View Post
There's another issue with OTL amps and Grados that hasn't been mentioned yet.

Some OTL manufacturers claim a fairly low ouput impedance for their OTL. Maybe they're right.

But you have to consider how they managed to pull this trick with relatively high output impedance tubes.

The usual trick is to crank up the negative feedback in the circuit. I don't quibble about negative feedback - a little bit can help stabilize the circuit. The problem is when you go heavy-handed with the feedback to force down the output impedance. It's like the difference between a pinch of salt in your soup and a handful of salt.

If you want to hear the difference feedback makes, track down an amp that doesn't use feedback at a meet. They (in my opinion) sound a world apart from an amp loaded down with feedback. You can also fiddle with a Bijou. It actually has a feedback control where you can adjust it from no feedback to a handful. Try it and see what you like - most prefer no feedback or a light touch.

Excessive feedback will strangle the music. Unfortunately, feedback is cheap to implemwnt and lets a manufacturer make all sorts of claims about the headphones cheap OTL will drive. Feedback is a bit of an esoteric concept and most people don't understand it. The average buyer mostly looks at the price and tuberolling capability. They don't lookat how the circuit operates, the quality of components or the build quality.

This is why I don't like cheap tube amps. In addition to pulling tricks like excessive negative feedback, they often use the very cheapest power transformers, have marginal filtering in the power supply, and are builton a PCB instead of point-to-point which is better suited to tubes.

If you're looking for quality amplification on a budget, just get solid state. I'm a tubehead, but the modestly priced solid state amps are really good. The difference is that you don't have to pay for a high voltage power supply for chips and a PCB is just fine. You'll get great sound from chips. If you want tubes, make sure the amp is built right with name brand transformers and uses a good circuit. That costs money. But you're much better off with a modestly priced solid state amp than a tube amp where every corner has been cut and the circuit jimmied with tons of feedback to bolster a marketing claim.
Fascinating. Thanks for that info. So what's your take on the Mapletree Ear+ HD then? Just curious.
post #56 of 58
I just got some MS-2's to go with my MS-1's with my Woo 3+ modified. They compliment well. Everyone who has came over and listened has been impressed.
post #57 of 58
Quote:
Originally Posted by dongringo View Post
Fascinating. Thanks for that info. So what's your take on the Mapletree Ear+ HD then? Just curious.
The Maple Tree has too shortcuts:

1. Cathode follower output (99% negative feedback, albeit local)

2. They use resistors on the output, this changes the frequency response/phase response of the headphones, maybe why people love them with Grados but I'd prefer to hear the design intent.

Just my 2 cents, but would like to hear from UE as he as more experience than me. Understand also that I have never seen a tube amp design without some compromises, well except Frank Cooters (no kidding.)
post #58 of 58
Quote:
Originally Posted by dongringo View Post
Scroll up to the top and click on the PRICES tube.

Welcome to Mapletree Audio Design
Thanks, but today I just pay for a WA2 with blackgate upgrade
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