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My Review of the Apex Pinnacle (and comparison to the 307a) - Page 5

post #61 of 96
Quote:
Originally Posted by pmillett View Post

 

So...

 

The Pinnacle is a 2-stage SE amp, using 6SN7 with LED bias as the first stage, capacitor-coupled (copper foil PIO)  to the PX4, which uses conventional cathode bias (run at fairly low current and voltage) as the second stage.  Transformer coupled input and outputs, with switches (inputs) and relays (outputs) to control balanced and unbalanced connections.  Relays are used to switch the audio path, so the signal path is direct.

 

The HV power supply is SiC shottky rectified, RCRC filtered in the power supply box and another LC in the amp box.  Isolated supplies are used for the two PX4 filaments, which use a somewhat complex combination of CCS in the PS box, and CM filtering and finally shunt regulation in the amp box.  Another seperate regulated supply generates the 6.3V for the 6SN7 and 5V to supply the LEDs and relays. 

 

Two delay circuits sequence the B+ and output mute relays.  There are also protection circuits to prevent HV from being applied to the outputs, and also to kill any HV on the umbilical cable if either end is unplugged.  (I've been designing equipment for almost 30 years (!) so I understand the regulatory safety requirements).


Hopefully that answers some questions - that's about as much detail as I think I should give!

 

Pete

 

 

And it's certainly more than you had to. Once again, thanks for being such a great contributor to the community. Anyone who is complaining should just not buy this and stop saying its overpriced. It's priced just fine for what it is. Todd and Pete have no history of price gouging and seem to be very fair and open.

 

If you don't like the price, don't buy the product. I won't, and I'll probably never be able to afford this, but Pete and Todd are keeping headphone Hi-Fi alive.

 

I can't believe how many people are coming after these guys for price when Todd is one of the best guys in the industry and Pete puts hundreds of hours into designing amplifiers that can be built by anyone with zero personal gain.


Edited by revolink24 - 12/14/10 at 12:18pm
post #62 of 96

Sounds pretty damn good to me, Pete! smile.gif
 

Quote:

Originally Posted by pmillett View Post

 

Hopefully that answers some questions - that's about as much detail as I think I should give!

post #63 of 96

I've been listening to it for the past two weeks and I'm still shocked about how much better it sounds than my current amps.  I wouldn't have believed it was possible without hearing and comparing for myself.

 

However, you do have to admit that most people do and should have some amount of scepticism with regards to price vs. performance -- not only with this amp, but of just about anything they may buy.  That's one of the reasons we are here -- to find real world reviews and experiences to let us determine the truth.  Most people on this board will readily admit there sure wasn't enough scepticism and questioning of Mikhails amps.  The issue in this thread is just more of how you voice that scepticism.  (And whether posters are telling the truth or not.  Hi regal!)

 

I'll sure regret sending on the amp and hope to purchase one soon.

post #64 of 96
Thread Starter 
Quote:
Originally Posted by pmillett View Post



 

Quote:
Originally Posted by FrankCooter View Post

I enjoy reviews and really appreciate all the work involved, but think that any review should start out with a simple generalised description of the circuitry of the component under review. I've read this entire thread, lots of adjectives and subjectivist impressions, but almost no technical information, My best guess is that we have a single ended two stage design, input transformer to handle either single ended or balanced inputs, a 6sn7 voltage amplifier with unspecified biasing, loading, and coupling. A  transformer coupled Sophia PX-4 dht for output duty, again with unspecified biasing, operating points, etc. And finally, a seperate B+ supply of unspecified type. I'm a big fan of Pete's work, and a little technical information would really be appreciated. I'm sure it's a wonderful amp. But would like to know why.

 

Frank -

 

As an engineer, I would agree with you.  But as a commercial product, is it really in Todd and my best interest to fully describe the circuit?  Certainly this isn't done in mainstream high-end.  I can't imaging the big boys giving any details of the circuitry...

 

I guess I am more worried about predujicing a potential customer, more than revealing any "secrets".  

 

On the other hand, anybody can open the amp up and figure this out.  And I suppose it is better to post the real information rather than allow people's guessing to influence others opinions!

 

So...

 

The Pinnacle is a 2-stage SE amp, using 6SN7 with LED bias as the first stage, capacitor-coupled (copper foil PIO)  to the PX4, which uses conventional cathode bias (run at fairly low current and voltage) as the second stage.  Transformer coupled input and outputs, with switches (inputs) and relays (outputs) to control balanced and unbalanced connections.  Relays are used to switch the audio path, so the signal path is direct.

 

The HV power supply is SiC shottky rectified, RCRC filtered in the power supply box and another LC in the amp box.  Isolated supplies are used for the two PX4 filaments, which use a somewhat complex combination of CCS in the PS box, and CM filtering and finally shunt regulation in the amp box.  Another seperate regulated supply generates the 6.3V for the 6SN7 and 5V to supply the LEDs and relays. 

 

Two delay circuits sequence the B+ and output mute relays.  There are also protection circuits to prevent HV from being applied to the outputs, and also to kill any HV on the umbilical cable if either end is unplugged.  (I've been designing equipment for almost 30 years (!) so I understand the regulatory safety requirements).


Hopefully that answers some questions - that's about as much detail as I think I should give!

 

Pete


Translation for me:   Amp sounds great!

post #65 of 96
Quote:
Originally Posted by DavidMahler View Post


Translation for me:   Amp sounds great!


 

Translation for me: some honest to goodness engineering and design went into this and no junk for the sake of junk. 

 

Thanks for posting Pete, I hope to give another one of your amps a listen in the not-to-distant future.


Edited by n_maher - 12/14/10 at 4:12pm
post #66 of 96

Pete, it certainly wasn't my intention to put you in an awkward position regarding proprietary information. Your gracious and detailed response goes far beyond my request for a basic circuit description. By putting a technical foundation under this review you have greatly elevated it's content and I would hope encouraged community interest. I am truly grateful for your generosity in sharing your work, not just here, but for your vast contributions to the diy community over the years. I use your web site constantly and have incorporated many of your ideas into my own projects. Now I know a bit about what makes this amp special! Hope you sell a bunch!

post #67 of 96

Hi All,

 

Just as a side note - there is a Pinnacle in shop and ready to ship. So if anyone wants one, I do have one built, ready and available! We will include free Fed Ex 2nd Day shipping on this one Pinnacle.

 

Todd


Edited by Todd - 12/15/10 at 12:31pm
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post #68 of 96

Quote:

Originally Posted by daveDerek View Post

(as i was asking Todd & Pete before but these questions weren't addressed:)  how does the apex pinnacle sound with 307a tubes, vs the px4s shown at canjam? would you recommend one over the other, or is more just a personal choice/flavor sort of thing? could you describe the differences between the 307a amp and the apex pinnacle. the 307a is a fantastic amp, and the new one costs considerably more than it's expensive predecessor. i'm sure i'm not the only one wondering what accounts for the price differential.

 

We actually never built a Pinnacle with the 307A.  It was a planned option at the beginning, but after the first one went together using the PX4, we decided to not even offer it with the 307A.  Both Todd and I liked the PX4 better.  Personally, I like the fact that the lower damping factor tightens up the bass a bit...

 

I would expect that with the 307A tube, the Pinnacle would sound a lot like the older 307A amp.  Both share the same basic circuit, with the major changes being in components (better transformers, mostly) and a different power supply (quieter).  These changes, as well as more expensive metalwork, are the biggest contributors to the Pinnacle's cost increase over the 307A.

 

Actually, I pretty much agree with David's review where he contrasts the two amps.  Most of the differences are due to the output tube characteristics.

 

Pete



 

post #69 of 96

thanks for your response Pete. it's very helpful.

post #70 of 96

is this the price $10.000 usd? 

post #71 of 96
Quote:
Originally Posted by audiophilefreak View Post

is this the price $10.000 usd? 



Yes.

post #72 of 96
Quote:
Originally Posted by Todd View Post

... there is a Pinnacle in shop and ready to ship ...


Er ... no there isn't.  Not anymore.  I apologize to my wallet.  Actually I'd like David Mahler and bdh to apologize to my wallet.  And Todd, for having one just sitting there.

post #73 of 96

yes, I no longer have a Pinnacle in stock and InnerSpace will soon have one in his possession. Thank you! Get your 6SN7 tubes ready to roll. They do make quite a difference in the sound of the amp! Any one else looking for a Pinnacle will have a 4-6 week wait if you order now!

 

Todd

Reply
post #74 of 96


Congratulations InnerSpace!  Great amp and preamp.  You will love it.
 

Quote:
Originally Posted by InnerSpace View Post



Quote:
Originally Posted by Todd View Post

... there is a Pinnacle in shop and ready to ship ...


Er ... no there isn't.  Not anymore.  I apologize to my wallet.  Actually I'd like David Mahler and bdh to apologize to my wallet.  And Todd, for having one just sitting there.

post #75 of 96

Just out of curiosity how did you justify buying a 10k headphone amp?
 

Quote:
Originally Posted by InnerSpace View Post



Quote:
Originally Posted by Todd View Post

... there is a Pinnacle in shop and ready to ship ...


Er ... no there isn't.  Not anymore.  I apologize to my wallet.  Actually I'd like David Mahler and bdh to apologize to my wallet.  And Todd, for having one just sitting there.

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