Which Mark Audio driver/tube amp would you choose?

[rvsixer]

Hello Everyone,

I currently have a diy OB build (cheapy Peerless 3" full ranger, 12" Peerless woofer helper, bi-amped with SS) that I enjoy very much, but want to take the full range driver to the next level.

Current situation/usage is as follows:
1) Room is a 10' x 14' upstairs loft area, vaulted ceiling (8' going to 12'), mostly open wall on the shorter walls (forcing speakers to the long wall, but this seems to work very well with OB). Love this setup as there is no head in vise listening required, and it fills the entire condo with listenable music. REW measures good to.
2) Usage is mostly 60dB@1m background music, occasionally "cranked" to 70-75dB (about 25% HT use at same base level, but of course need added headroom for HT).
3) Music of choice is mostly classical, jazz, alternative/classic rock, 80's new wave. Sources for background music are 192k internet stations (sometimes 128k, NOTHING below that), more serious listening is FLAC rips off CD and LP, HT is TrueHD/Master DTS etc.
4) I am not an "audiophile" or basshead per se, just looking for great sound, with a balance of enough resolution to make classical music shine, and 192k internet rock radio non-fatiguing.
5) Build will eventually become a full HT using same driver (i.e. center and surrounds).

My research has led me to Mark Audio produced drivers; specifically Alpair 7.3, CHR-70, CHP-70, CHBW-70, or EL70. I am worried about the Alpair 7.3's being too "true" to the source and causing fatigue on internet radio sources, and on the other something like the CHP-70 (with its high end rolloff) making good sources "dull".

I realize this in an exercise in compromise, just trying to home in on the best compromise. These new drivers will be driven by a new DIY tube build ~500USD budget, all recommendations welcomed. I am currently thinking of a Dynaco ST-35 clone build with EFB mod (Dave's Lab), seems high enough caliber for these drivers, with enough power to experiment with other speaker types in the future.

[planet10]

Originally Posted by rvsixer

My research has led me to Mark Audio produced drivers; specifically Alpair 7.3, CHR-70, CHP-70, CHBW-70, or EL70. I am worried about the Alpair 7.3's being too "true" to the source and causing fatigue on internet radio sources, and on the other something like the CHP-70 (with its high end rolloff) making good sources "dull".

Given your requirements, EL70. Just be patient with them as they break-in.

dave

[markaudio]

Originally Posted by rvsixer

Hello Everyone,

Current situation/usage is as follows:
1) Room is a 10' x 14' upstairs loft area, vaulted ceiling (8' going to 12'), mostly open wall on the shorter walls (forcing speakers to the long wall, but this seems to work very well with OB). Love this setup as there is no head in vise listening required, and it fills the entire condo with listenable music. REW measures good to.
2) Usage is mostly 60dB@1m background music, occasionally "cranked" to 70-75dB (about 25% HT use at same base level, but of course need added headroom for HT).
3) Music of choice is mostly classical, jazz, alternative/classic rock, 80's new wave. Sources for background music are 192k internet stations (sometimes 128k, NOTHING below that), more serious listening is FLAC rips off CD and LP, HT is TrueHD/Master DTS etc.
4) I am not an "audiophile" or basshead per se, just looking for great sound, with a balance of enough resolution to make classical music shine, and 192k internet rock radio non-fatiguing.
5) Build will eventually become a full HT using same driver (i.e. center and surrounds).

My research has led me to Mark Audio produced drivers; specifically Alpair 7.3, CHR-70, CHP-70, CHBW-70, or EL70. I am worried about the Alpair 7.3's being too "true" to the source and causing fatigue on internet radio sources, and on the other something like the CHP-70 (with its high end rolloff) making good sources "dull".

Hi Rv
Looking at your situation (well described 1 to 5), from my perspective in terms of driver design, you're likely moving into CHR-70 territory. The original design objective of the CHR was to be an all-round Full-Ranger at an affordable price. The latest Gen. 3 model retains this original concept while extending performance. Many CHR's serve duel stereo audio and HT purposes, used in paired box designs, or with woofs and subs where more low output is desired.

I'm thinking mostly from the "technical" perspective re your intended set-up. Its largely how I thought CHR's might be used in these sorts of applications. In my studio, I use Mac I-Tunes radio (ambient, jazz and classic music mainly) via an Airport feeding a vintage Sony Mofset TAF 333 EX amp to CHR's in BR boxes. This is my studio's general every-day set-up. Looking at the Dave's Lab link, a mod Dynaco ST could be a nice amp/driver combination.

Thanks
Mark.

[chrisb]

Another nice contender in the same general weight class as the Dyna ST35 would be George Anderson (Tubelab) Simplepushpull. I built mine with EL84s and come recycled vintage Scott output iron. Running in pentode mode( the OPT had no UL taps) it has more than adequate power for Alpair 7s or dual EL70s per side.

My upstairs system is 2 channel music only, sourced by MBP>Airtunes>AEX toslink>Citypulse DAC>EL84P/P>dual EL70s. Occasionally I'll bypass the Airtunes and direct connect optical out from MB - big difference of course, but for non-critical listening the easy way is fine.


I also have a variant of Eli Duttman/Jim McShane "El Cheapo" - with EL84 as well - this time in triode/no feedback. It could be argued that it has an edge over the pentode amp in terms of that 3-D (pseudo) triode cream as Harvey would have described it, but with drivers like any of the Mark Audio Alpairs (or the EL70 second cousin), it's been my listening experience that the more power the better.

The downstairs system is a Denon HT receiver and 5.1 of Alpair7(.1), dual corner mounted woofers, and Alpair6M surrounds. When streaming music from Airtunes or playing the FM radio, the Alpairs are far less forgiving of the combination of source quality and the processing circuitry in the receiver. This is a less than natural system for serious music only - but of course for HT/cinema when the bulk of cerebral processing is engaged in the visual, and since much of the sound engineering is exaggerated for a larger than life perspective for which we voluntarily suspend our disbelief, the shortcomings of these particular electronics are moot.

This is one of those rigs with a not particularly intuitive control function - i.e. if there is a simple one-button bypass function, it's buried deep in the instruction manual. When I play direct from a CD player ( Jolida 603)>TubelabPP> Alpair7 Pensils, the system is transformed into something very musical.

In other words, the Alpairs have more than enough resolution to reveal the qualities of upstream components - a double edge sword, that.

[rvsixer]

Thank you Dave and Mark for your informative replies, very helpful and much information to ponder. Both of you do so much for the DIY community.

Okay need to look at the EL70 and CHR-70. How to choose between paper or metal ?

Just a more detailed check if you please, want to make sure this has a chance of working:
1) Proposed setup is bi-amped LCR speakers, EL70/CHR on top in OB (left and right driven by tubes 17W per channel, center channel 30W SS).
2) Dipole 12" woofer helpers on the bottom, crossed at ~150-200Hz driven by 100W SS per channel.
3) Sealed rear EL70/CHR single driver surrounds.

I hope this will get me close to a budget friendly setup, that is good for stereo music firstly, some HT secondly. No subwoofers due to cool (and quiet!) neighbors in the condo next door. Want to stick to bipole/dipole mains for the same reason (current OB's are placed perpendicular to neighboring wall, and measured levels are down 5-6dB by the time they reach there). Gotta' love North American paper mache housing .

[rvsixer]

Thanks chrisb also, I got your post after my last response. I will take a look at the tubelab and el cheapo as well!

[chrisb]

hmm, metal vs paper? between the two named ( CHR / EL) , I'd take the paper.

Keep in mind that in properly processed cinema mode, the center is predominant channel of the front row, and I'm not so sure that you wouldn't hear some differences in between the tube and SS amps.

As my own system is one of the 7.1 receivers with 5 channel amps and pre-outs for LFE and either front height or rear-surrounds, but not for the "main 5", I've not had opportunity to test the thesis, but suspect that the surrounds / height effect channels would be less critical of matching amps.

That all said, it sounds like you've got an interesting rig planned

[Assesears]

Hi,

I have a pair of CHP-70, for my ears they are superb I think these are going to be my favorite full ranges. The mid band is to die for, percussion instruments sound so real i'm well made up with them just what i'm looking for not heard anyother MA drivers so just my pennies worth.

Ta

[mashaffer]

My set up is similar to yours (Radio Shack 5 1/4" Foster OEM with Goldwood 10" helper). My plan for amplification is SE UL 6LU8 (Kegger's "$250 amp" configuration) for the FR With the same tubes PP for the woofers using tube preamp with custom crossover.

The little 4" MA drivers should do nicely I think for the FR part and probably be much less shouty than my rat shacks. I would think that 200Hz or so would be the right crossover especially if using those smaller drivers. You could go lower with larger FRs but with OB I think it makes more sense to cross higher and let the helpers do the heavy lifting.

[rvsixer]

Good info, keep it coming.

chrisb: The Simple PP looks like a great solution for me, I am pursuing it further. Regarding the center amp, it will be interesting to see if I can notice differences or not. I am hoping that by using an identical driver and speaker config they will be minimized. If not, well another amp build is warranted .