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A very difficult decision here but I've decided to sell my classic Orange AD15 valve combo amp with the intention of using the proceeds to get into the exciting world of camera drones !!. I've always loved this amp but for most of it's time it's been some very impressive bedroom furniture and I'd rather be getting out and flying cameras.
Photo By Steve Bromley.
P.S. Just for the record it did not sell but I'm still happy as I got my drone thanks to advice from fellow Flickr member John Welles saving money buying the cheaper but still significant Phantom 3 Standard. So I could keep this wonderful little amp.
Spec:
V1 - Brimar 6059/CV4006 (6BR7/CV2135)
V2 - Westinghouse 6FQ7/6CG7
V3/4 - Tung Sol 7581A
V5 - JJ GZ34S
Figured I could use 6L6GC and it's variants in my EL34 valve amplifier after some checks using LTspice. Fitted some Tung sol 7581A to test out. Cathode biasing seems to work nicely. Plates sit at 428V and screens just below at 427V via 43% UL taps. Output transformer is a 6.6K load which appears to be near perfect for the 6L6. Small bonus is the reduced heat output from the lower heater current (0.9A vs 1.5A)
So far, listening, it sounds every bit as good as the other EL34's and their derivatives. I figure the ~20dB of negative feedback is minimizing any audible differences there may be between the various valves I've tried.
Acoustic Energy Evo3
Mission M72
Mission M7C2
Lovan Speaker Stand
Lovan Classic II Audio Rack
JVC 29" TV
Onkyo TX-SR701 Receiver
Yaden AVR100 and 500 auto voltage regulator
Pioneer SACD/DVD-Audio/VCD/DVD-Video Player
Denon CD Player
Duntonic DU2i Integrated Tube Amp
AudioSpace AS6 Integrated Tube Amp
Cayin MT35 Tube Integrated Amp
Ixos 6003 and Ecosse CS2.3 speaker cables
Ecosee The Composer and Van Den Hul D102 MK3
interconnects
Home made valve power amp based on the old Mullard 5-20 with some fairly significant tweaks.
Valves:
GE 6267
GE JAN 6CG7/6FQ7
Electro Harmonix 6CA7EH
Sovtek 5AR4
Iron:
Sowter UA21 outputs
Primary Windings mains
VVT chokes
Current schematic:
After my hi-fi had sat more or less dormant for months and months, a curious little chain of events eventually led me to make what might seem a fairly rash purchase the other day, in the shape of a Valve Amp, and suddenly I am re-discovering my CD collection and bathing in silky smooth audio luxuriousness.
I had one in my childhood years - inherited from my parents - and remember the glow of the valves fondly. Then in much later years I was re-acquainted with valves care of guitar amps. And now I have gone and bought myself a new valve amp. It is expensive, spectacularly heavy and I love it. I did wonder before the purchase about the wisdom of buying a pricey piece of gear based on technology stretching back about 80 years - would there be hum from the speakers? Would the bass be flabby and indistinct? Would it be a total disaster (I had heard all sorts of stories about horrible amp - speaker mismatches)? Well, it sounds bloody wonderful. And that's without it's visual charms.....
Brushed my teeth? Did the washing up? No, I turned on my hi-fi and relaxed to some chilled out music, basking in the glow of my lovely valve amp. Such a pleasant change to gawping at some nonsense on the TV. I really ought to do it more often.
My valve amp was a huge extravagance. It cost an awful lot of money. One could question whether the sound it makes is that much different to the sound a "tranny" amp produces. Well, I do prefer the sound and I LOVE the look of the thing. My previous amp was a featureless black metal box with knobs on it. The valve amp is a chunk of shiny metal with eight beautiful little glass bottles protruding from it, putting out this wonderful colour combination - created by heat and large amounts of electricity furiously charging around inside. What an eye-candy-fest!
I shot this amp some time ago - see the photo below. To my slight disappointment I didn't manage to come up with anything much new in terms of composition, but I much prefer this new shot in terms of colour and exposure.
Valves:
Mullard EF86
GE JAN 6CG7
Electro Harmonix 6CA7EH
Sovtek 5AR4
Iron:
Sowter UA21 outputs
Primary Windings mains
VVT chokes
I've made some changes to the design as the gain was too high and I couldn't resort to simply increasing the feedback in order to reduce it. The change allowed for a reduction in open loop gain and also a small increase in feedback level too. This successfully dropped the gain from 49.54dB open loop and 33.26dB closed loop to 45.77dB open loop & 25.87dB closed loop. That also took feedback from 16.5dB to 19.9dB.
Current schematic:
Brook audio amplifier, 1950s "HiFi" design. Brook's all-triode amplifiers, such as this one with 2A3s, are legendary. Working examples are sought-after highly by some audio enthusiasts.
The Modern Consumer: 1950s Products and Style
San Francisco International Airport (SFO)
The Modern Consumer (SFO Museum web site):
www.sfomuseum.org/exhibitions/modern-consumer
SFO Museum:
Rock-Ola "Model O" amplifier, part of a friend's 1946 Model 1422 jukebox.
Like most old vacuum tube (or "valve") amps, this one needed new filter capacitors as well as a few other repairs. Its tube lineup is very simple, with a 6J5 pre-amp tube and a pair of 6L6 beam-power output tubes. The rectifier is a 5Z3.
I'll post more pictures of the jukebox after I re-install the amp.
A 20-watt push-pull circuit design tube monoblock power amplifier that packs a whallop. Internal parts are already upgraded to audiophile quality such as Mundorf Supreme signal caps, Multicap RTX power filter bypass caps, Riken RMG resistors, shielded Silver signal wire, Nichicon Power Filter caps, multi-way binding posts, automotive paint end bells, and stainless allen screws. Tube compliments are: ASL 6L6 power tubes and ASL 12AT7 driver tubes.
Brook pre-amplifier and control unit, 1950s "HiFi" design. Brook's all-triode amplifiers are legendary. Working examples are sought-after highly by some audio enthusiasts.
The Modern Consumer: 1950s Products and Style
San Francisco International Airport (SFO)
The Modern Consumer (SFO Museum web site):
www.sfomuseum.org/exhibitions/modern-consumer
SFO Museum:
Mark IV prototype which has been under test for about 2 months.
Specifications are:
Brimar 6059/CV4006 input pentode running as pentode (Industrial version of a 6BR7)
GE 6CG7/6FQ7 phase splitter as LTP with a 2SC2611 used as a constant current sink in the tail
Tung-Sol EL34 push pull output at ~450V with cathode bias (around 19-20W idle dissipation using zeners to tighten things up towards fixed bias)
Sowter UP-21 output transformers, VVT chokes & Primary Windings HT transformers.
Rock-Ola "Model O" amplifier, part of a friend's 1946 Model 1422 jukebox.
Like most old vacuum tube (or "valve") amps, this one needed new filter capacitors as well as a few other repairs. Its tube lineup is very simple, with a 6C5 pre-amp tube and a pair of 6L6 beam-power output tubes. The rectifier is a 5Z3.
This close-up shows the tone controls, which are only accessible by removing the back from the jukebox.
I'll post more pictures of the jukebox after I re-install the amp.
Replaced the stock rubber feet of the Cayin LA34 with these aluminum feet. Rubber feet are good for solid state amps but not on tube amps that are heavy and generate extreme heat.
The dimension of the new aluminum feet is the same with the stock feet, except i had to drill the hole a tad bigger each to fit in the stock screw.
I noticed a significant sonic improvement.
When my friend Mark acquired this Fender Pro Reverb guitar amplifier, it had a number of serious problems, but it looked good and seemed to be a promising project.
"Silverface" Fender amps have a mixed reputation, as do models such as this one which use an ultra-linear output circuit to boost its power to an advertised 70 watts.
Most of the components in this amp had 1979 date codes, but a few had early 1980 codes. My best guess is that the amp was first sold sometime in 1980.
NOTE: All trademarks are the property of their owners.
Altec 604-8G Completed but unpainted. Now inside and ready for trials some trials. See more of these speakers and the manufacture of the 620a Cabinets here e-trade.ie/altec/
I don't just them as much as I should and would consider selling them on as complete speakers only. If interested, mail me.
Finally, I've finished my PL519/PCL82 SE Amp.
Was testing the Canon Remote Software thing a bit. Very long exposure time (25 minutes) with a very small aperture value (f22).
One finished but unpainted 604 and 620a Speaker. See more of these speakers and the manufacture of the 620a Cabinets here e-trade.ie/altec/
I don't just them as much as I should and would consider selling them on as complete speakers only. If interested, mail me.
Some of the original tubes were in good condition, but substitution showed that four of the 6AU6 pentodes in the pre-amp section were weak and/or noisy. I replaced them with 1980s vintage US military tubes that sound good.
It's interesting to note that this amplifier does not use any of the 12-series twin triodes that were (and still are) so popular with amplifier designers. All of the small-signal tubes are pentodes.
The Japanese "NEC" brand 6V6GT output tubes were in good condition, so there was no need to replace them.
Another view. See more of these speakers and the manufacture of the 620a Cabinets here e-trade.ie/altec/
Altec 604 Speaker mounted in Cabinet. See more of these speakers and the manufacture of the 620a Cabinets here e-trade.ie/altec/
I don't just them as much as I should and would consider selling them on as complete speakers only. If interested, mail me.
This is the new 300b SE Tube Amp Chassis for one channel. It was water-jet cut from 3mm aluminium sheet and then folded.
Spec:
V1 - Brimar 6059/CV4006 (6BR7/CV2135)
V2 - Westinghouse 6FQ7/6CG7
V3/4 - Tung Sol 7581A
V5 - JJ GZ34S
Figured I could use 6L6GC and it's variants in my EL34 valve amplifier after some checks using LTspice. Fitted some Tung sol 7581A to test out. Cathode biasing seems to work nicely. Plates sit at 428V and screens just below at 427V via 43% UL taps. Output transformer is a 6.6K load which appears to be near perfect for the 6L6. Small bonus is the reduced heat output from the lower heater current (0.9A vs 1.5A)
So far, listening, it sounds every bit as good as the other EL34's and their derivatives. I figure the ~20dB of negative feedback is minimizing any audible differences there may be between the various valves I've tried.
Altec 604 Speaker Mounted inside Cabinet. See more of these speakers and the manufacture of the 620a Cabinets here e-trade.ie/altec/
The vinyl covering on this Teisco amplifier is unique.
There are two "Normal" inputs and one "Treble" input, instead of the two (or four) inputs found on many other amps. All three inputs are controlled by the single bass, treble and tone controls.
The reverb is called "Echo," and the jacks for the tremolo and "Echo" switching pedals are on the front of the amp. The power switch looks like a replacement.
This is an interesting little amp, and I've never seen another one like it.
My neighbours are really loving this little guy..... I can hear them tapping along when I play it... ;o)
Filth!
Originally was going to use a pair of Mission Labs 520's but later sold these and used a pair of KR 300b Tubes
Sorry for the scruffy finish but it is still being fine-tuned and turned therefore upside down still quite a bit. It uses a pair of KR Audio 320 Driver Tubes, a GZ37 Rectifier and 6SN7 input tube. This is the Left side of a mirror image pair. The Chassis was water-jet cut from 3mm sheet Aluminium.
The design and layout is the Walton Audio MkIII by Derek Walton, so all thanks to him for the support and guidance throughout the project. Actually he is one Guy I know has the full set of Sound Practices from new. I only have them as a PDF.
Altec 604 Speaker in Excellent Condition. See more of these speakers and the manufacture of the 620a Cabinets here e-trade.ie/altec/
The Completed Monoblocs - Thanks to Derek Walton for the help and advice along the way!
These now power a pair of Altec 604-8G Drivers in the large 620a Cabinets. There are some images of these being made in the Audio Speaker Set in my Photostream! If you ever want to make some and need the drawings please ask!
Thanks
I had this strap made by a leather worker, he's on instagram @sharps.workshop very happy with how it turned out, to replace the original worn out one.
Rock-Ola "Model O" amplifier, part of a friend's 1946 Model 1422 jukebox.
Like most old vacuum tube (or "valve") amps, this one needed new filter capacitors as well as a few other repairs. Its tube lineup is very simple, with a 6C5 pre-amp tube and a pair of 6L6 beam-power output tubes. The rectifier is a 5Z3.
In this picture you can see the speaker socket on the back of the chassis, in the middle. The board to the right has a jumper that is used to select the total number of speakers, from one to four. It also includes terminals for connecting additional speakers and an optional remote volume control.
I'll post more pictures of the jukebox after I re-install the amp.