Description

Working on optimizing an alternative analog stage for my dac designed by John Swenson. Discrete, current mirror mosfet stage powered by 3 discrete regulators.
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Components Toggle details

    • Tonian Acoustics TL-D1
    Wideband driver with ribbon supertweeter. A real keeper!
    • Twin TDA1541 NOS DAC
    Switchable 6DJ8 and 6C45 tube output stage.
    • Modded Squeezebox with Master Clock Input and I2S Out
    A John Swenson designed synchronous reclocking circuit that transforms the Squeezebox into a high-end transport.
    • Krishu Magnetic Volume Control
    S&B MKIII Transformer Volume Control with Elma Switch
    • Welborne Labs DRD 300B
    monoblocks with KR Audio 300B tubes
    • Q-Audio Tao Analogue Interconnect
    We don't need no stinkin' RCA's! Ultra low mass Ampmodu high tension connector. Tao IC's used throughout system.
    • Canare Starquad
    17 foot run with locking bananas
    • Blue Circle Audio MR1200 Music Ring
    For both source and amp
    • Harmonic Technology Pro AC 11
    Power cord for Dac
    • Eichmann Technologies eXpress Power AC
    For the power conditioner
    • DIY Rack: IKEA Lyte
    High strength, extremely low energy storing mass and has good internal damping characteristics. Original design by Ken Lyon of Neuance Audio. Still one of the best improvements for my system.
    • Herbie's Audio Lab Hal-O Tube Dampers
    Used on all tubes in Amp and CDP
    • Herbie's Audio Lab Iso-Cup Big Tenderfeet w Ebony Ball
    Underneath DAC

Comments 38

Showing all comments by mikemarv.

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Owner
Hi Seth,

I like the starquad cable. It has relatively good inductance, capacitance and resistance specs in an affordable cable that is flexible. I use one cable run per speaker. So there's a set of banana plugs on each end of a cable run for pos and neg pole of each speaker. Yes, it is effectively 11 awg. I've also used the belden cross-connect cable with spade termination and found it to be too stiff and a hassle as I work on different DIY amps frequently. Particularly with tube amps and higher efficiency speakers, I've found that one does not need the ultra low resistance and capacitance required by a solid state / less efficient speaker interface.

mikemarv

Owner
System edited: Working on optimizing an alternative analog stage for my dac.

mikemarv

Owner
System edited: Replaced all IC's with Q-Audio Tao Analogue Interconnects. Nice improvement. Very neutral, hi-rez cable. Surprisingly (given the cables unshielded design) my system is now dead quiet.

mikemarv

Owner
System edited: New KR Audio 300B tubes.

mikemarv

Owner
The mods to the SB are pretty simple. This circuit works for a DAC that accepts i2s input. The bulk of the effort is in building a reclocking circuit on a 3x4" perfboard. This board is mounted in one's DAC; I mounted mine vertically. There's a high quality 11.2896 MHz clock on this board that generates a master clock which is sent back to the SB and soldered to the pad vacated after removing the existing crystal. You then intercept three signals (SDATA, LRCK, BCK) on the SB board and send them to the new board where they are re-synchronized by the same clock and sent to the dac chip. The results are amazing. I have posted a long thread on Aslyum here:
http://www.audioasylum.com/forums/pcaudio/messages/2/24319.html

and I have posted a board layout on Slim Devices here:
http://forums.slimdevices.com/showthread.php?t=38967

John generously posted the schematic back in Jan '07 on Slim Devices. I'd be happy to reply to any Qs you may have after reading these threads. Anyone with intermediate soldering skills and able to read a schematic can pull this off. Cheers ~ Mike

mikemarv

Owner
System edited: Now free of CeeDees! Added a modded Squeezebox to be used as a transport that accepts a master clock input and outputs signals in left justified format (similar to I2S).

mikemarv

Owner
Good to hear from you David and sorry for the late reply! The changes have been slow and gradual but at this point I guess the cumulative changes reflect a new system. Some time back I decided to commit to assembling a system based on single ended triode amplification and a non-oversampling digital source. The system reflects these goals notwithstanding a little more DIY work that I'd like to do on cabling and power supplies. Happy Listening!

mikemarv

Owner
System edited: Replaced Canare Star Quad speaker cable with Belden 89259 Cross Connect Coax cable with Cardas spades. Nice improvement. Better frequency extension at both ends. Slightly better resolution. Although designed as bi-wire, I am doubling up the run since I have only one pair of binding posts.

mikemarv

Owner
System edited: Added 2 dedicated AC circuits

mikemarv

Owner
Mark, thanks for you kind comments. Nice system you have there. I really like the Welborne amps. Very simple circuit. As far as music server, the mac mini is really alluring. What a great little package. As I'm starting out, I think I'm going to bootstrap my way into pc audio. The server is the only thing I haven't yet figured out. I have a usb-to-i2s board on order that will snap into my dac...so it will have no spdif in the chain. I want to use a pda with a decent size screen like the tapwave zodiac and use salling clicker for remove control. I've read recent feedback that Jriver has come a long way as far as a comprehensive solution including ripping. I'm sure there will be some trial and error involved. My winter project!

mikemarv

Owner
System edited: Recently completed a tda1541a NOS Dac. New mahogany chassis with ebony knob from thingamaknob

mikemarv

Owner
System edited: After 3 weeks of no music, we have new speakers

mikemarv

Owner
System edited: Once the audio signal leaves the Dac, there's a total of 2 capacitors and 1 resistor in the signal path. Pure and simple :)

mikemarv

Owner
Millikeith, that's a terrific system that you've managed to assemble. DH labs seems like a good choice for your components. In the price range of the components we are using, resolution is one limiting factor relative to more expensive gear. So, with choices in cabling, we don't want to work against enabling our components to resolve as much of the recording as possible. The Eichmann Express is value oriented and very good. I have not used it directly plugged into the amp. I bought it for the power conditioner that feeds all my components. I think it is a great value. The one negative is that it is bulky, long and bright blue. If it's hidden none of these things matter. I can safely recommend it. Other good values to consider are: VHAudio, Black Sand Violet, and TG Audio. Some have 100% return policies. Buy 2, and keep the synergistic one. Also, Usedcable.com has a cable library from which you can rent a few cables to determine what's best for your system. I've read enough posts to appreciate that cabling is very system dependent. I enjoyed material improvement from replacing my outlet with ACME cryo or similar....a quick cheap upgrade. The cheap IKEA Lyte DIY rack offered a significant improvement in resolution and imaging. I've found that all these things work together to enable the components to play at their best.

mikemarv

Owner
Millikeith, sounds promising. Kevin would know since he used to sell them. Please let us know how it turns out. Mike

mikemarv

Owner
Ssglx, I could not agree more with your observation about use of vibrapods under speakers (at least mine). I have a raised foundation with hardwood floors which may influence decision on method of vibration control. I'll just repeat your quote as it mirros my own experience.

"Achieved the clarity bass punch and definition and additional PRAT that I was looking for without the fatigue I got with cones."

mikemarv

Owner
Millikeith, sorry for the late reply. Just returned from our annual vacation to Brazil yesterday. The prologue 1 is an excellent value. The amp is extremely well built. I live close to Upscale Audio so I had the luxury of auditioning this amp prior to purchase. I listened to the more expensive Unison Research sand/tube hybrid, but preferred the more immediate presence of the Primaluna. I've heard the Primaluna with three speakers, all of which are not considered to be hi-eff: Yaras, Opera Superpavarottis and Sonus Faber Concertos. The Primaluna drove all of these with ease. You asked about the bass response. To my ears, the bass quality is very good, with excellent timbre and dimensionality. It sounds tight on less complex music such as small scale jazz and acoustic music, not lacking in any material way. I listen to a lot of acoustic music: bossa nova, flamenco, jazz. The amp is an excellent choice for these genres. The bass is more challenged on more dynamic material such as orchestra and rock, but very good at this price point. The amp is dead quiet, and I cannot emphasize this enough. I would match this tube amp with speakers of reasonable efficiency (i.e. >90db) with a relatively flat response curve. The Yaras are a superb match.

mikemarv

Owner
Hi Plinko, I added the Herbie tube dampers more to further refine my system than to correct an audible vibration problem. In my system, the audible difference is subtle but everything is a bit more tight. The reviews for Herbies compare favorably to other products and they offer a no trouble return policy, so you might as well try. I added the Rack before the tube dampers, and the rack made a material audible difference.

mikemarv

Owner
System edited: Added Herbie's HAL-O Tube dampers to all tubes

mikemarv

Owner
System edited: Built a DIY Lyte Rack using IKEA Lack end tables. Designed by Ken Lyon as an affordable alternative to his stellar Neuance platforms.

mikemarv

Owner
System edited: Added Blue Circle MR1200 balanced power unit fed by Eichmann eXpress AC power cord. Now hearing low level info on certain CD's I never new existed.

mikemarv

Owner
System edited: I am planning to install dedicated AC lines for my system. I'd welcome your feedback to this method. Thanks!

mikemarv

Owner
Jh2os, very pleased with the Yaras. Distribution in the U.S. is thin, and this makes them hard to audition. I'd be curious to know how the Prologue Two compares to your former Cayin? You've got a great system; I've heard terrific things about the Cairn Fog, and I considered the Totem One monitors.

mikemarv

Owner
Ya, I feel like I won the lotto with this amp. I'm not familiar with the Technics source, but I think the Tjoeb would add considerably to your enjoyment. The open architecture design of the Tjoeb makes it very flexible. In addition to experimenting with different tubes, there are 3 op-amp combos that you can try...all for under $50 a pop. This unit is terrific even without the upsampler. You can augment the unit in phases, and experiment with the op-amps first. The difference being that the Upsampler adds bass extension, offers a larger soundstage and more midrange bloom. Finally, for my speakers, the vibrapods made a HUGE difference, as if I had a completely different speaker. More bass and better imaging.

mikemarv