Stuff For Sale and Feedback

For feedback, reviews, please go down to the bottom of this page. Thank you!

 

Hi there,

I added this page for people interested to buy equipment designed and built by me. For other people’s design I can only give advise for personal implementation.

Please fell free to add you comments and feedback.

 

Coming soon:

  • new 01A preamp coming soon in the products zone (Winter 2017/2018)
  • 300B amp in design progress. Hope by the end of the year

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NOW FOR SALE

1.

Here is another audio gem. This is the “Shiny Eyes” 45-C3g DHT amplifier, built with care and to provide a rewarding sound. This is an audiophile amplifier and it is not for everyone. It delivers up to 2W output. These 2W sound bigger than it shows. It is indeed a 2,000,000 microWatts. It is meant to be used with high sensitivity speakers. I listened to its sound using recently built TangBand 1772-W8 full range driver speakers. These are 96 dB sensitivity and fills the 300sqft room. For concert levels,a 100dB+ speakers are required.

The amplifier has 4 and 8 ohms outputs  through a switch and Cardas binding posts.  The output transformer are James 6123HS and the interstage transformers  are  Lundahl LL2762. The 45 tubes filaments power is supplied through a Coleman regulator. Therefore there is a need to adjust the filaments every time the tubes are  replaced. A 5V high quality Simpson meter is used for this purpose. The amp comes with a manual where there are easy to follow instructions on how to adjust the filament voltage.

The power supply has a separate enclosure. The high voltage uses a Hammond 278X, high quality Chicago Standard Chokes 10H/180mA chokes and 6AX4 tube rectifiers. The setup is choke input for a better sounding amp. The high voltage delivered to the amp is measured and shown on a nice Simpson 500VDC panel meter. There are 3 raw, well filtered and regulated DC supplies : two for the 45 filaments and the third for the C3g filaments. The power is supplied to the main amp through an umbilical cord that carries only DC. The connector is Amphenol military grade. This way the AC is kept away from the main amp and the amplifier is dead quiet on my 96dB speakers.

All the components are high quality and audio grade where needed, such as Nichicon KG, Takman, Mills, Elna Cerafine, Clarity caps, ASC Oil caps, Mundorf Mlytics.

The amplifier comes with all the tubes : NOS 6AX4 – 2 pieces, pair of 45s test NOS RCA black plate and pair of C3g NOS Rohre.

The amplifier shows a dominant 2nd Harmonic that confers the absolute astonishing sound of a DHT from that era. One of the picture shows the harmonics and THD and one can observe that the THD superinposes almost perfectly on the 2nd harmonic. The maximum THD is 3.8% at 2W ( naturally second harmonic), the frequency response is better than 20-20KHz +/-1dB, the input sensitivity is 0.8Vrms for 2W output, the input impedance is 51Kohms and the damping factor is 4 on 8 ohms.

The enclosures are hand made using American cheery nicely finish with 4 coats of Oil and Urethane, and sanded aluminum 1/8″ top plates.

Despite the fact that I tried to keep the cost as low as possible, the price of this amp is high because I didn’t cut corners when I’ve designed it.

This is a well built amp to last for a long time.( more of my work can be seen on simplepleasuretubeamps). I am very fond of the sound of the 45 tube and therefore I’ve built a few 45 amps and always pleased with the results.

Email @ simplepleasuretubeampsrct@gmail.com  for inquiries

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2.

My latest built is a solid state amp. I wanted to try for a while the LM3875 and I bought the kit from Peter @ Audiosector.com  

I’ve also have a pair of nice Vu meters ( https://www.jlmaudio.com/shop/sew-315-vu-meter.html ) from JLM audio and their kit ( https://www.jlmaudio.com/shop/vu2-stereo-vu-buffer-kit.html ).

My idea was to fit it in the same size Modushop enclosure that I use for the 4P1L preamplifier.

Here are some pictures:

I had a 18V dual secondaries Triad medical grade transformer and this was a perfect fit. The amp sounds very clean and musical. It delivers max 25W on 8 ohms and has an input sensitivity of 1.27 Vrms for full power output. The measured frequency response is 20Hz-40KHz@-0.1dB and THD lower than 0.01%. I tried it with my newly built speakers ( full range 95dB) and they are a great fit. I’m using a 4P1L preamp, which is also a nice combination. The preamp fits perfectly on the top of the amp and the combo is a great option for whoever owns 90+dB speakers  and wants a tube preamp sound touch. The combo is also kids and pets friendly ( everything is inside the boxes).

More pictures:

I am selling the amp and the 4P1L preamp as a combo. If interested please contact me @ simplepleasuretubeampsrct@gmail.com.

 

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12 thoughts on “Stuff For Sale and Feedback

  1. I can heartily recommend anything that Radu builds. I purchased a 301A DHT tube preamp from him through EBay last year. It is built like a tank and very carefully thought out. Adds that wonderful DHT goodness to my system which has a Pass Labs solid state amp and single driver speakers. Radu even customized the preamp for me in order to drop the gain a bit.

    It is hard to believe that he makes money on these builds. He seems to be doing it for love of the endeavor! Highly recommended.

  2. I bought a 4P1L and F4 combo through eBay Radu. It sounds excellent. After that, I asked Radu to built a 26/01A tube preamp for me. He also fixed the hum issue for my amplifiers. This is the best experience I have ever had in my 20 audiophile years. The 26/01A performs just like a 10k and above preamp. The sound opens up just like a real live concert.

    Radu is knowledgeable and considerate. Through multiple projects with him, he is always keeping customer first in his mind and makes you extremely happy and surprise by going extra miles.

    Radu is the best! Highly recommended. Jim

  3. Hi Radu,

    Having researched your projects, I would also be very interested in your 26/01A DHT preamp. Please email me with details.

    Best, George

  4. I had built preamplifiers with 4P1L tube by myself. After 6 months of tuning it, I found that this tube is difficult for me despite its great sound. Finally, I had given up.

    But its sound was awesome, I googled for 4P1L preamp at times. And fortunately, I found Radu’s website and I purchased 4P1L preamp from Radu.

    In short, it’s really awesome.
    3D-stage, natural tone, and transparency. I can hear what I wanted. And absolutely no noise.
    Its bass is not huge, but it grips.
    And for the chassis, it’s better than it looks in photograph.

    I can recommend it to whoever loves DHT’s sound. You cannot know its sound before you hear it.

  5. I would highly recommend any of Radu’s build projects. Radu last year built me a Statement
    101b,26 tube preamplifier. OUTSTANDING,,in finish as well as build. Hand picked top of the Line parts quality and sonics several categories above the commercial priced companies.
    Which you pay huge50% markups. Here that money goes directly into the top quality Lundahl transformers, powder coated,pinstriped top and front panels and writting of my choosing.
    Custom Precision Electronics.Myself a 35 years Audiophile, this is perfect for the quality
    that I require. Since then Radu has built me a Pass Labs Dual Mono First Watt F-6 amplifier .
    I could not recommend any higher any Audio designer, Technician ,PJ Letteri.

  6. Hi Radu,
    What would be the cost of the 01A DHT Line Stage and the 101D/26 DHT switchable preamp,
    fully built as described?

    • Hello Daniel,
      I’ve sent you an email. I’m no longer building one enclosure DHT preamps. DHTs are very sensitive and capture hum from a nearby transformer or tube rectifier..
      Keeping the AC away from the main preamp enclosure is a must in order to have a very low noise DHT preamp.
      Cheers,
      Radu

  7. Hi Radu

    I’d be interested in using a 4p1l design either for preamp/buffer duty or for ‘powering’ my compression drivers (active horn system). I thought about a single stage (one single 4p1l) per channel, no driver. Gain is not an issue because the compression drivers’ sensitivities are markedly above 110dB and I’m listening in the near field.

    Questions:
    -Would the noise (DHT design) be a problem in my setting?
    -Would it be possible to use this amp indifferently as preamp or as amp? Note that the impedance of the compression drivers is relatively high (32 ohm).

    • Hi Marc,
      4P1L is a very nice tone tube. However, it is quite microphonic at lower signal levels. Using as a final stage in a power amp, the signal levels are high ( up to 100Vrms) and the microphonics are manageable, The tube goes through a warm up period of 10-30 minutes where one will hear pings. After reaching a steady thermal state there should be no noises besides the ones created by airbourne waves ( microphonics).
      Your driver is pretty sensitive. Lets assume you only need 0.25W average power to create a good listening sound pressure level. This translates to 2.82Vrms at the speaker level. I would use LL2765/30mA in 12:1 configuration. The 4P1L will average an 8x gain loaded to the LL2765. Therefore, with only one stage you will need about 4.3Vrms input to get 0.25W on your driver.

      Hope this answers your questions.You can email me at simplepleasuretubeampsrct@gmail.com if needed.
      Cheers,
      Radu

  8. Radu designed and built for me a pair of amazing mono-block amps 26>>>46>>>50
    All I can say here is that they are flawlessly working and successfully competing with more expensive products. He is a dedicated professional and a fair and honest person. Highly recommended !!

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