Thursday, April 5, 2018

Garrard 301 - minor restoration

ca. 2003

I acquired this early grey grease-bearing model at a Hamfest around '96. I was the only person willing to shell out $240, which was the firm asking price of an elderly gentleman.

Attic - ca. 2009

It travelled back to Manila with me in '08 where it had to endure the extreme humidity of the tropics. Despite the adverse conditions, its performance remained very stable during the 8 years spent there.

The original grey hammer tone finish had deteriorated due to corrosion so I asked my assistant to mask the important mechanical bits. 😉


I think she did a pretty good job. What do you think? 😁


I used Rust-oleum silver hammerite spray paint which is a lighter shade than the Garrard original.  


I cleaned, flushed and re-packed the main bearing with 2 NGLI grease. The motor had no issues, so I just put a few drops of oil. Unlike the E50 motor in the Thorens TD124 which needs periodic motor servicing, I've never opened the motor on this 301.


When I acquired the unit, the power switch was already broken. I've had this spare speed selector switch in my parts bin for over 15 years courtesy of my buddy Joel. While waiting for the paint to cure, I cut and filed it down to function as a power switch.

Not a bad fit. 😎


I cleaned up 15 years of dust and soot build up on the plinth and then applied sealer and wax.


Here's to many more years of service! 🍻

Sunday, March 25, 2018

XtremPro X1 USB DAC

I was too wound up after playing a gig one winter Sunday evening. Watching episodes of the Grand Tour over a couple shots of Ballantine Scotch Whiskey was not enough to relax my mind. So I ended up "window" shopping on Amazon. 

This tiny USB DAC piqued my interest and I thought I could use it for my Lenovo laptop. Given that the above specs were very similar to my current AQ Dragonfly Black at less than 1/3rd the price, I bought it and called it a night.

 A shootout with the AQ Dragonfly Black was inevitable. I will just admit outright that this $29.39 USB DAC blew away the Dragonfly Black! The XtremPro X1 is more dynamic, transparent across the audio band and extended at both frequency extremes. Although I'm just a casual headphone listener, the healthier output voltage of the X1 was also an advantage through my 90s vintage Grado SR60 cans. 

Unfortunately, the XtremPro X1 does NOT work with iOS devices as-is (see update below) but there were no issues with the aforementioned Lenovo and my 2013 MacBook Pro. 

Apparently, this USB DAC has had quite a following in Europe

Important Update!

As suggested by a kind reader, Miguel (see comment below), 
this issue
can be by-passed through a generic 2 port USB 2.0 Hub. This Eyeboot model from Amazon did the job for $5.99. 

How to:

Plug the 2 port USB hub wall wart to an AC source,  
XtremPro X1 DAC > 2 port USB hub > iOS camera adapter > iOS device, plug your headphones to the 3.5mm socket or connect to your preamp or integrated amp, happy listening!

XtremPro X1 + Eyeboot 2 port USB Hub = great value for the money!



Thursday, March 8, 2018

Audio Silente parts for the Thorens TD124 + Mk. II

Thorens TD 124 Mk. I + Stax UA3NL

My Thorens TD 124 Mk. I and Mk. II have seen so much action and deserved pampering.

The heavy iron platter created a "dome" on the main bearing end cap of the Mk. I.

Both sides of its original Nylatron thrust pad were dented. So this past weekend I went on eBay and ordered two sets of 6mm bronze end caps that each came with two plastic thrust pads and gaskets, an idler wheel + a few other TD 124 bits from Simone Luchetti of Audio Silente.

Backyard around 11am, 3/7/18

Shipping was swift, the parts were delivered by FedEx from Rome, Italy yesterday morning before the height of the blizzard.

I started work on the main bearing of the Mk. I.

Fit and finish are first rate!

Since the unit was already on the work bench, I cleaned and lubricated the motor also.

Although the original main bearing end cap on the Mk. II was not as dented as the Mk. I, I also replaced it for future generations. 😁

Given the attention to detail Swiss engineers put into the design of the TD 124, that flimsy main bearing end cap was a gross oversight. The finely machined 6mm bronze end cap from Audio Silente definitely adds structural integrity to the main bearing. I also noticed that the platter spins at least twice as long after the motor is shut off = less friction. 

While testing the Audio Silente idler wheel on the bench, I realized that even if the rubber was still supple on my original idler wheels, the bearings were not as silent as the Audio Silente idler, perhaps due to wear. While deciding whether to order another idler wheel from Simone or Oilite bearings from the Spanish guy, we lost power...😞

With about 2 hours left of daylight, I consoled myself by looking at audio porn. 😎

Thorens TD 124 Mk II + Audio Technica AT1501-II

 The idler wheel comes with 3 extra O-rings - 2 red and another black. Because the pre-installed black O-ring already starts faster than my stock idler wheel,  I did not try the red silicon O-ring which is supposed to give an even quicker start.

The Audio Silente idler wheel truly lives up to its company name. I had never been able to bring the performance of my TD 124s to this level of silence.  


Bravo Simone!


Reference


 For maintenance and restoration information, visit The Analog Dept. Thorens TD124 webpage!👍👏 

Tuesday, February 20, 2018

Conquering RFI in the 2C22/7193


Noisy and unstable 2C22/7193

Moving closer to civilization, this lovely sounding triode used as a voltage gain stage in my SE2A3 mono integrated amp had stability issues due to RFI. 



Since I persist in using these antediluvian devices, I had to find a solution.


A 150 ohm 1/2W CC resistor with the leads cut short soldered in series with the grid cap (insulate with heat shrink tubing) >> shielded cable terminated by an RCA plug (shield connected only at the RCA jack side) >> RCA jack (barrel grounded to chassis) solved the stability issue.

A well behaved 2C22/7193 

Thursday, February 1, 2018

Altec 32A, 32C, Emilar EH1210, EH800, EH500 and Faital Pro STH100




This is a cumulative report on horns I listened to and tested from May 2016 until the end of 2017. All the tests were done through the mono hifi rig using the above Altec 802 compression driver fitted with a GPA 34852 diaphragm + an Altec 414A in a repurposed Altec 861 cabinet running in full-range mode tied together by a 6dB/octave high pass crossover/EQ hinged at 2500 Hz. 

Altec 32A and 32C


Altec 32A (top)
Altec 32C (bottom)

 The Altec 32A (metal) and 32C (plastic with ribs) horns are lineal descendants of the Western Electric 32A horn as found in the WE753 speaker system. I've had the plastic 32C since '09 and lived with the metal 32A for over a year and can say that these are the most sophisticated native 1" horns I've heard and owned to date.

Altec 32A


Altec 32A

Altec 32A + 802 + 414A

Altec 32C


Altec 32C

Altec 32C + 802 + 414A


Metal or plastic? 


It's ironic that the later plastic 32C sounds more vintage than the earlier metal 32A. Definitely, the longer throat of the earlier 32A and the type of material used for construction influence the sound. But in what capacity, I cannot surely define. The iPhone RTA results reinforce the cooler and more modern sound I hear from the metal 32A versus the warmer and sweeter plastic 32C.

The magnitude of difference is not great. Similar to the 20275 vs. 34852 Altec 1" aluminum diaphragms - distinct enough not to be used as a stereo pair but still excellent performers in their own right. However, those who are expecting a front-row presentation may find both these horns too laid back.

Watch out for roughly finished throat edges in the 32A which are detrimental to performance. So far all the plastic 32Cs I've seen have very smooth throats.

Emilar 


As soon as I landed in the US in May 2016, I tried to collect the Emilar horns talked up by Joe Roberts in his war against the devil's trumpets before they became unaffordable. 😉

EH1210


Emilar EH1210

Emilar EH1210 + 802 + 414A

This wasn't recommended by J-Rob but it was cheap enough to try. The EH1210 has the most extended high frequency response according to the iPhone RTA but subjectively it was the least refined sounding horn in this group. I think one can do much better with some modern offerings, see the last entry below. 

Emilar "Bowtie" EH800 and EH500


Emilar EH500 (left) + Emilar "Bowtie" EH800 (right)

WARNING: these two Emilar horns are heavy cast jobs, doing the audiophile knuckle test can result in serious injury! 😃

EH800


Emilar "Bowtie" EH800 

EH800 + 802 + 414A

If you are looking for a modern sounding horn with a more forward presentation but without the shout and distortion of the Altec 811, then this is the horn for you. Exciting sound but guaranteed not to make your ears bleed. 

I think the low end cut-off at 800 Hz spec is a bit optimistic. For maximum satisfaction start around 1200 Hz and work upwards.

EH500


EH500

EH500 + 802 + 414A

This is a native 2" horn with a finely machined 1" - 2" throat adaptor. Once again I find the 500 Hz cut-off an overestimation for a horn of this size. I'd start crossing around 900 Hz and up. 

My ears do not agree with the iPhone RTA. I found this horn to be mellower than the EH800 "Bowtie." The tonal balance of the EH500 is somewhere in between the Altec 32A/B/C and the EH800.

EH500 in Large Format Mode


EH500 sans adaptor + Renkus-Heinz SSD3301

With the JEL N1600 XO in tow, I removed the 1"-2" throat adapter and bolted the 2" exit Renkus-Heinz SSD3301 directly to the horn to sample large format tones. I got juicy mids and smooth highs from this combo.

Late addition:


Faital Pro STH100


Faital Pro STH100

I wanted to sample what can be had off the shelf at Parts Express for under $100 and ordered a pair of these small aluminum tractrix horns by Faital Pro.

STH100 + 802 + 414A*

*RTA was done at a later date in another location,
hence the difference in low frequency response 

With the Altec 414A running full range and the STH100/802 combo crossed at approximately 2500 Hz, I got very clean (if a bit dry) high frequency harmonic augmentation with no nastiness at all. To my ears, this tractrix horn is preferable to the EH1210.

CODA


For the past 4 years, I've been blogging about horns and compression drivers. Justifiably, the horn/driver combo seasons the speaker system's sonic flavor. However, these components only cover the upper three octaves of the audio band (mostly harmonic overtones). I would be remiss if I didn't stress the greater importance of the Altec 12" 414 woofer/midrange because it is tasked to reproduce most, if not all, of the fundamental notes in music from 30 Hz to 4000 Hz. That's seven octaves, practically the frequency range of a piano.  

I've been trying, but so far haven't found alternative 15" or 12" woofers that play the midrange as well as the Altec 414. The good news is, Bill Hanuschak of Great Plains Audio told me last year that they still re-cone 414s and their product page lists an Alnico 414-8B(16B)

Wednesday, January 17, 2018