GUILTY PLEASURE 845 INTEGRATED SINGLE ENDED TRIODE STEREO AMPLIFIER
Introducing The Guiltly Pleasure
The Guilty Pleasure, currently a prototype, is in development as a product. This is an integrated stereo single ended triode amplifier with antique appearance and construction methods. Power tubes are the legendary 845 triode. First released by RCA in 1931, the 845 tube saw extensive use in RCA AM radio transmitters. Gain tubes are the legendary chrome dome Sylvania 6SN7 or 12SN7. Wiring is point-to-point. The power supply relies heavily on huge oil capacitors. Whereas a typical setup with a preamplifier and a power amplifier has 7 active stages, the Guilty Pleasure has 4. I have heard nothing to compare with this amplifier's musicality . . . rich, textured bass, intoxicating mids, delicate highs, and total musical involvement. The wonderful musicality of the Guilty Pleasure is attributable to heavy reliance on oil capacitors in the power supply and to having only 4 active stages. For market niche, compare the Guilty Pleasure to the Audio Note Kondo or Audio Note UK Ongaku amplifiers, The price is $49,950 USD.
The Guilty Pleasure, currently a prototype, is in development as a product. This is an integrated stereo single ended triode amplifier with antique appearance and construction methods. Power tubes are the legendary 845 triode. First released by RCA in 1931, the 845 tube saw extensive use in RCA AM radio transmitters. Gain tubes are the legendary chrome dome Sylvania 6SN7 or 12SN7. Wiring is point-to-point. The power supply relies heavily on huge oil capacitors. Whereas a typical setup with a preamplifier and a power amplifier has 7 active stages, the Guilty Pleasure has 4. I have heard nothing to compare with this amplifier's musicality . . . rich, textured bass, intoxicating mids, delicate highs, and total musical involvement. The wonderful musicality of the Guilty Pleasure is attributable to heavy reliance on oil capacitors in the power supply and to having only 4 active stages. For market niche, compare the Guilty Pleasure to the Audio Note Kondo or Audio Note UK Ongaku amplifiers, The price is $49,950 USD.
History
Twenty years ago, in Fall of 2001, at Age 63, I visited the Vacuum State of the Art Conference (VSAC) in Silverdale Washington, hosted by the creative and intrepid Dan Schmalle of Bottlehead fame. Inspired by remarkable DIY projects on display, I returned to VSAC in 2003 with a self designed and constructed integrated stereo single ended triode amplifier. Each channel uses a Sylvania chrome dome 12SN7 gain tube (identical, except for heater voltage, to the acclaimed 6SN7 tube). The 12SN7 tube drives a 6AU5 cathode follower tube, which drives the remarkable 845 power tube. I named the amplifier Guilty Pleasure because of all the billable hours I gave up to design and build it, and because of all the pleasure I had in executing the design and build.
Twenty years ago, in Fall of 2001, at Age 63, I visited the Vacuum State of the Art Conference (VSAC) in Silverdale Washington, hosted by the creative and intrepid Dan Schmalle of Bottlehead fame. Inspired by remarkable DIY projects on display, I returned to VSAC in 2003 with a self designed and constructed integrated stereo single ended triode amplifier. Each channel uses a Sylvania chrome dome 12SN7 gain tube (identical, except for heater voltage, to the acclaimed 6SN7 tube). The 12SN7 tube drives a 6AU5 cathode follower tube, which drives the remarkable 845 power tube. I named the amplifier Guilty Pleasure because of all the billable hours I gave up to design and build it, and because of all the pleasure I had in executing the design and build.
Appearance
While designing the Guilty Pleasure I got caught up in the mystique of early vacuum tube equipment. I found myself seeking to emulate the look of equipment that might have been found in Thomas Edison's Menlo Park Laboratory. This explains the choice of the mahogany cabinet, the brass and copper fittings, the old-time knurled nuts used on the binding posts, the old-time knobs, and the large meters. Polished copper lifting handles secured with polished brass brackets were provided to make it more easy for one young person or two older people to lift the considerable 60 pound weight of the main amplifier module. This does not include the 20 pound weight of the power supply module. The glow of the tall 845 tubes in a darkened room is romantic to behold. Labels and name plates will be engraved.
While designing the Guilty Pleasure I got caught up in the mystique of early vacuum tube equipment. I found myself seeking to emulate the look of equipment that might have been found in Thomas Edison's Menlo Park Laboratory. This explains the choice of the mahogany cabinet, the brass and copper fittings, the old-time knurled nuts used on the binding posts, the old-time knobs, and the large meters. Polished copper lifting handles secured with polished brass brackets were provided to make it more easy for one young person or two older people to lift the considerable 60 pound weight of the main amplifier module. This does not include the 20 pound weight of the power supply module. The glow of the tall 845 tubes in a darkened room is romantic to behold. Labels and name plates will be engraved.
More History
For years the Guilty Pleasure languished in our living room driving mid efficiency speakers. With the power transformer on the main chassis the amplifier the the hum level was too high for use with high efficiency speakers.I eventually moved the power transformer onto a separate chassis connected to the main chassis with an umbilical cord. This reduced hum to a minimal level. Nonetheless, the Guilty Pleasure took years to find its way to the Altec A7 Voice Of The Theatre speakers in the GOED.
For years the Guilty Pleasure languished in our living room driving mid efficiency speakers. With the power transformer on the main chassis the amplifier the the hum level was too high for use with high efficiency speakers.I eventually moved the power transformer onto a separate chassis connected to the main chassis with an umbilical cord. This reduced hum to a minimal level. Nonetheless, the Guilty Pleasure took years to find its way to the Altec A7 Voice Of The Theatre speakers in the GOED.
Musical Pleasure
My first hearing of the Guilty Pleasure integrated stereo amplifier with the Altec A7 Voice Of The Theatre Speakers spoke to me with an effect something like God 's command to Moses to build the Ark. The music was overwhelmingly beautiful. I played piece after piece of random selections from the enormous library of music on my music hard drive. Every piece of music sounded the most enjoyable I'd ever heard it, analog or digital. Then came vinyl with the same result. It seemed the Cosmos was telling me to build a product version of this amplifier.
Speaker Sensitivity
With speaker sensitivity at or above 97 dB/w/m, and in a residential setting, the 15 watt output of the Guilty Pleasure produces all the power needed to play music with extreme beauty as loudly as one could wish for. At ordinary volumes volumes the Guilty Pleasure makes gorgeous music with speaker sensitivity as low as 89 dB/w/m.
Amplifier Circuit and Construction
Amplifier Voicing: The 845 power output tube was selected for its beautiful voice, high power output (for a single ended tube amplifier), availability, good looks, and reasonable price. Even the least inexpensive Shuguang 845 tube sounds like heaven in this amplifier. The 6AV5 driver tube (later changed to 6AU5) was selected on the basis of experience with a Bogen DB 230A integrated push pull amplifier which gives lovely sound using 6AV5 output tubes. The 6AU5 tubes replaced the 6AV5 tubes because the 6AU5 sounds better. The 12SN7 tube was selected knowing that one is hard pressed to find lovelier sounding gain tubes than the 12SN7 (12.6 volt heater) and its better known sibling the 6SN7 (6.3 volt heater). The Guilty Pleasure has both 6.3 and 12.6 volts AC available on chassis. A switch will be added to allow use of either the 12SN7 or the 6SN7.
Adjustable Bias For Each Power Tube: The grid voltage is separately adjustable (fixed bias) for each of the two power tubes allowing the user to select the plate current (as indicated by the large plate current meter) for best sound and tube life. Currently the prototype Guilty Pleasure is running with the 845 tubes at 800 volts on the plate and 80 ma plate current. I plan to experiment with resistors in the power supply to optimize the power at clipping versus sound quality. This is on the order of 15 watts per channel. While an 845 single ended tube amp can be designed to produce 24 wpc, my experience is that design for higher power may conflict with design for musicality.
Premium Power Supply: By definition a B+ power supply provides the high voltage to the vacuum tube anodes (or plates). From early radio B stands for battery. The B+ power supply of the Guilty Pleasure uses a full wave bridge comprised of great sounding HEXFRED soft recovery diodes driving a 1600 volt, 45 uF input capacitor comprised of stacked 400 volt electrolytic capacitors with bleed resistors. Following the input capacitor, the power supply splits into left and right channels, each beginning with an RCRC filter (resistor/capacitor/resistor/capacitor) which drops the voltage to 800 or 900 Volts DC B+ for the 845 tubes. These first of these capacitors is a 1600 volt, 135 uF stacked electrolytic. The second is a hulk of an oil capacitor rated at 27 uF and 700 volt AC (990 volt DC). A subsequent RCRC filter in each of the power supply channels drops the voltage to 500 volts B+ to meet the needs of the 6SN7 or 12SN7 (selectable) gain tubes and the 6AU5 cathode follower tubes. Large oil capacitors are used in these lower voltage RCRC circuits.
Oil capacitors: The oil capacitors selected for the B+ power supply were chosen because they make beautiful music. Oil capacitors are seldom selected for a B+ power supply because they are too costly, too large physically, and too heavy to be used for the B+ power in a practical audio amplifier product. The most practical and least beautiful sounding capacitors for B+ power are electrolytics. The next most practical, and sometimes better sounding capacitors for B+ power are metalized polyethylene film capacitors. The best sounding capacitors for the B+ power are huge oil capacitors, which are impractical for large market products. The Guilty Pleasure is a very special prestige product, for which we can accept the product size weight and cost penalty associated with massive oil capacitors.
Wood Chassis: The use of wood in the main and power supply chassis is ideal for artisan construction and, along with the classy looking 845 tubes, the classic early electronics look. While I think the amplifier best exemplifies the Thomas Edison look in mahogany, it might also look smashing in black ebony, or another wood chosen by the buyer.
Metered Power Output Tubes: Meters on the penthouse console of the Guilty Pleasure amplifier allow the user to read the quiescent current and the voltage of each of the power tubes. The variable resistors which adjust power tube plate current are hidden just inside ventilation holes of the console, easily accessible with a long straight bit screwdriver (included with the amplifier) from outside the console. Individual adjustment of plate current in each power tube allows the current in the two tubes to be adjusted and matched, even with some drift in tube characteristics over the long life of the power tubes.
Removable Umbilical: The umbilical between the main chassis and the power supply chassis is presently captive. This will be changed by adding connectors at both ends of the umbilical. The power cord receptacle, fuse holder, RF filter, power transformer, and high voltage filter will occupy a separate power module chassis styled like the main chassis.
Design For Easy Maintenance
As engineer and designer, I have chosen components and assembly methods intended to minimize requirements for maintenance, and to simplify maintenance. All resistors and capacitors directly associated with vacuum tubes are located on the underside of the chassis top panel. The top panel is hinged at the rear (piano hinge) to allow opening for easy component access. A novel feature is that most resistor and capacitor connections under top plate are made with Euro style terminal blocks, eliminating many solder joints and providing direct wire to wire contact. This greatly simplifies replacement of resistors and capacitors in the unlikely event a replacement is needed. In advancing the Guilty Pleasure to a commercial product it is my intent to build the mains power supply components, the two 845 tube heater supplies, and the 845 tube bias supply in modules, which can be easily removed and replaced for servicing.
Reliability Track Record: Wiring is point to point. There are no printed circuit boards to age and fail. The only failures experienced with the existing Guilty Pleasure amplifier in 18 years of use are with meter switches, and one cathode follower resistor.There have been no connection failures, no capacitor failures, and no diode failures. The cathode follower resistors each operate at 7 watts dissipation. Three 3-watt resistors in parallel, nine watts total rating, were not up to the punishment. This will be addressed with a pair of 10 watt resistors in parallel, providing a 20 watt rating. More rugged toggle switches will be implemented.
Reliability: I will source better switches and use a higher resistor power rating for the cathode follower resistor.The final product design will be safe, fully and lucidly documented, and easy to work on, so that any competent vacuum tube electronics technician can quickly restore the amplifier to its original performance in the rare event of a component failure.
Maintainability: Maintainability is assured by point to point wiring (the absence of printed circuit boards), modular construction (allowing modules to be removable for access), and by thorough and lucid service documentation. All components directly associated with the vacuum tubes and transformers are located on the underside of the hinged top plate. When the top plate is rotated up, the full array of these components is directly viewable and accessible. Likewise, the top plate of the penthouse console and the top plate of the power supply module are hinged to allow direct access to components.
Amplifier Features
Stand Alone: The Guilty Pleasure is a stereo integrated amplifier. An external line stage is unnecessary when the amp is used with mid to high efficiency speakers. This reduces the number of active stages from 7 to 4, resulting in a substantial improvement in clarity, separation of voices, pin-point imaging, and sense of space.
A wide variation exists in the characteristic sound of stand-alone line stages and preamplifiers. The gain stage of the Guilty pleasure serves as a built-in line stage with a neutral voice, providing wonderful sound and simplifying the overall system. While not ideal, external line stages are sometimes found necessary to voice a system; but all things equal, fewer gain stages are better.
Remote Stepped Volume Control: The prototype version of the Guilty Pleasure has a stepped stereo volume control (2 dB per step) with discrete resistors. The product version of the Guilty Pleasure will have a remote stepped volume control (2 dB per step) with discrete resistors. In the remote volume control only two resistors will be active in the volume control circuit at any volume level.
Balance Control: A separate gain control ahead of each channel of the volume control allows the user to lower either of the channels from zero to six dB to achieve system balance. Using a system without control of balance is like driving a car which pulls right or left . . . a constant annoyance.
Stereo/Mono Switch: A stereo/mono switch is located on the front of the penthouse console.
Volume Control Sensitivity Range Switch: A switch is included which allows the user to change the volume control sensitivity by 8 dB to best adjust the volume control range to system sensitivity.
Multiple inputs: Six sets of inputs are provide on the rear panel, along with easily accessible selector switches on the rear panel, one for each channel. The separate selector switches allow the user to play just one channel at a time for diagnostic purposes.
4, 8, and 16 Ohm Taps: Easily accessible binding posts are provided for 4, 8, and 16 ohm speakers. Switches for the power tube current and voltage meters allow the user to check left and right channels or turn the meters off.
Standby Switch: At present the amplifier is set up with an on/off switch to power the heaters and a standby switch to apply power to the plates. Both switches will remain in the product. In operation, the user will be able to use the standby switch to defeat plate power when it is desired to have the amplifier in the standby mode. Cathode life can be extended by switching the standby mode during shut-down until the plate voltage has fallen (as indicated by the plate voltage meter), before turning the amplifier off with the on/off switch..
Backup Vacuum Tubes Provided: Each Guilty Pleasure amplifier will come with a pair and a spare pair of each of the three vacuum tube types, housed in a deluxe padded wood box.
Delayed Startup: The product version of the Guilty Pleasure amplifier will have an automatic timer to apply power to the plates after the heaters are turned on. This will assure that the cathodes are hot before the plates receive power, preventing gradual damage to the cathodes.
Documentation: Lucid documentation will be provided.
Turning The Guilty Pleasure Amplifier Into A Product
I am currently enjoying the design and development activity of turning the Guilty Pleasure stereo integrated amplifier into a no-holds-barred luxury 845 amplifier product. The Guilty Pleasure amplifier comes to the market in a price range consistent with the associated design and development activity, component costs, and labor, putting the product out of the reach of many audiophiles and music lovers. I have tried to keep my products priced to allow many audiophiles own them. However advancing the Guilty Pleasure prototype amplifier to an ultimate level product competitive with the expensive and prestigious Ongaku 211 amplifiers and similar products is labor intensive. I once telephoned a man named Whitney. When he picked up the receiver I gave my name and asked if this was Mr. Whitney. He answered, "Yeah, what's left of him." At 83 years old I have accumulated a wealth of knowledge about things audio, much of which comes to bear on the Guilty Pleasure amplifier. With other products to deliver, I can produce one Guilty Pleasure unit a year. I expect to produce 5 units in the next 5 years.The goal is to have the first commercial Guilty Pleasure amplifier available to the first person on the waiting list in December of 2022.
I would not consider making this amplifier into a limited production product unless I had fallen absolutely in love with it. The amplifier is crying out to become a product. Still crazy after all these years, I look forward to filling a waiting list for 5 Guilty Pleasure amplifiers, one per year, at a price of $49,950 per unit. I have a waiting list ready to accept orders with an initial $1000 deposit. When it is clear that an order is near fulfillment, an additional $4000 will be required to complete the deposit, with the balance due just before shipping. Names will go on the waiting list in the order received. If a purchaser has a change of heart before delivery, or if I am unable to complete the spoken-for amplifier, the deposit will be immediately refunded to the purchaser.
Hear The Guilty Pleasure For Yourself
Call Pete Riggle at 509 582 4548 to make an appointment to hear the Guilty Pleasure amplifier in a system with Altec A7 speakers, Hiraga circuit crossovers built by Pete Riggle, and a 29 foot long subwoofer horn built by Pete and friends. This invitation is open to all, but is particularly important if you or someone you know may be in a position to own one of the few of these amplifiers to be built. I can particularly vouch for the performance of the Guilty Pleasure amplifier driving Altec A5 and A7 loudseakers.
What is Next?
A great deal of product optimization, redesign, component sourcing, fabrication, testing, critical listening, and documentation, are underway to turn the Guilty Pleasure into a prestige audiophile product. It will be a pleasure to take orders to build these wonderful amplifiers for a few very special owners.
All my best to those who have chosen to read about the Guilty Pleasure.
Kind Regards,
Pete
My first hearing of the Guilty Pleasure integrated stereo amplifier with the Altec A7 Voice Of The Theatre Speakers spoke to me with an effect something like God 's command to Moses to build the Ark. The music was overwhelmingly beautiful. I played piece after piece of random selections from the enormous library of music on my music hard drive. Every piece of music sounded the most enjoyable I'd ever heard it, analog or digital. Then came vinyl with the same result. It seemed the Cosmos was telling me to build a product version of this amplifier.
Speaker Sensitivity
With speaker sensitivity at or above 97 dB/w/m, and in a residential setting, the 15 watt output of the Guilty Pleasure produces all the power needed to play music with extreme beauty as loudly as one could wish for. At ordinary volumes volumes the Guilty Pleasure makes gorgeous music with speaker sensitivity as low as 89 dB/w/m.
Amplifier Circuit and Construction
Amplifier Voicing: The 845 power output tube was selected for its beautiful voice, high power output (for a single ended tube amplifier), availability, good looks, and reasonable price. Even the least inexpensive Shuguang 845 tube sounds like heaven in this amplifier. The 6AV5 driver tube (later changed to 6AU5) was selected on the basis of experience with a Bogen DB 230A integrated push pull amplifier which gives lovely sound using 6AV5 output tubes. The 6AU5 tubes replaced the 6AV5 tubes because the 6AU5 sounds better. The 12SN7 tube was selected knowing that one is hard pressed to find lovelier sounding gain tubes than the 12SN7 (12.6 volt heater) and its better known sibling the 6SN7 (6.3 volt heater). The Guilty Pleasure has both 6.3 and 12.6 volts AC available on chassis. A switch will be added to allow use of either the 12SN7 or the 6SN7.
Adjustable Bias For Each Power Tube: The grid voltage is separately adjustable (fixed bias) for each of the two power tubes allowing the user to select the plate current (as indicated by the large plate current meter) for best sound and tube life. Currently the prototype Guilty Pleasure is running with the 845 tubes at 800 volts on the plate and 80 ma plate current. I plan to experiment with resistors in the power supply to optimize the power at clipping versus sound quality. This is on the order of 15 watts per channel. While an 845 single ended tube amp can be designed to produce 24 wpc, my experience is that design for higher power may conflict with design for musicality.
Premium Power Supply: By definition a B+ power supply provides the high voltage to the vacuum tube anodes (or plates). From early radio B stands for battery. The B+ power supply of the Guilty Pleasure uses a full wave bridge comprised of great sounding HEXFRED soft recovery diodes driving a 1600 volt, 45 uF input capacitor comprised of stacked 400 volt electrolytic capacitors with bleed resistors. Following the input capacitor, the power supply splits into left and right channels, each beginning with an RCRC filter (resistor/capacitor/resistor/capacitor) which drops the voltage to 800 or 900 Volts DC B+ for the 845 tubes. These first of these capacitors is a 1600 volt, 135 uF stacked electrolytic. The second is a hulk of an oil capacitor rated at 27 uF and 700 volt AC (990 volt DC). A subsequent RCRC filter in each of the power supply channels drops the voltage to 500 volts B+ to meet the needs of the 6SN7 or 12SN7 (selectable) gain tubes and the 6AU5 cathode follower tubes. Large oil capacitors are used in these lower voltage RCRC circuits.
Oil capacitors: The oil capacitors selected for the B+ power supply were chosen because they make beautiful music. Oil capacitors are seldom selected for a B+ power supply because they are too costly, too large physically, and too heavy to be used for the B+ power in a practical audio amplifier product. The most practical and least beautiful sounding capacitors for B+ power are electrolytics. The next most practical, and sometimes better sounding capacitors for B+ power are metalized polyethylene film capacitors. The best sounding capacitors for the B+ power are huge oil capacitors, which are impractical for large market products. The Guilty Pleasure is a very special prestige product, for which we can accept the product size weight and cost penalty associated with massive oil capacitors.
Wood Chassis: The use of wood in the main and power supply chassis is ideal for artisan construction and, along with the classy looking 845 tubes, the classic early electronics look. While I think the amplifier best exemplifies the Thomas Edison look in mahogany, it might also look smashing in black ebony, or another wood chosen by the buyer.
Metered Power Output Tubes: Meters on the penthouse console of the Guilty Pleasure amplifier allow the user to read the quiescent current and the voltage of each of the power tubes. The variable resistors which adjust power tube plate current are hidden just inside ventilation holes of the console, easily accessible with a long straight bit screwdriver (included with the amplifier) from outside the console. Individual adjustment of plate current in each power tube allows the current in the two tubes to be adjusted and matched, even with some drift in tube characteristics over the long life of the power tubes.
Removable Umbilical: The umbilical between the main chassis and the power supply chassis is presently captive. This will be changed by adding connectors at both ends of the umbilical. The power cord receptacle, fuse holder, RF filter, power transformer, and high voltage filter will occupy a separate power module chassis styled like the main chassis.
Design For Easy Maintenance
As engineer and designer, I have chosen components and assembly methods intended to minimize requirements for maintenance, and to simplify maintenance. All resistors and capacitors directly associated with vacuum tubes are located on the underside of the chassis top panel. The top panel is hinged at the rear (piano hinge) to allow opening for easy component access. A novel feature is that most resistor and capacitor connections under top plate are made with Euro style terminal blocks, eliminating many solder joints and providing direct wire to wire contact. This greatly simplifies replacement of resistors and capacitors in the unlikely event a replacement is needed. In advancing the Guilty Pleasure to a commercial product it is my intent to build the mains power supply components, the two 845 tube heater supplies, and the 845 tube bias supply in modules, which can be easily removed and replaced for servicing.
Reliability Track Record: Wiring is point to point. There are no printed circuit boards to age and fail. The only failures experienced with the existing Guilty Pleasure amplifier in 18 years of use are with meter switches, and one cathode follower resistor.There have been no connection failures, no capacitor failures, and no diode failures. The cathode follower resistors each operate at 7 watts dissipation. Three 3-watt resistors in parallel, nine watts total rating, were not up to the punishment. This will be addressed with a pair of 10 watt resistors in parallel, providing a 20 watt rating. More rugged toggle switches will be implemented.
Reliability: I will source better switches and use a higher resistor power rating for the cathode follower resistor.The final product design will be safe, fully and lucidly documented, and easy to work on, so that any competent vacuum tube electronics technician can quickly restore the amplifier to its original performance in the rare event of a component failure.
Maintainability: Maintainability is assured by point to point wiring (the absence of printed circuit boards), modular construction (allowing modules to be removable for access), and by thorough and lucid service documentation. All components directly associated with the vacuum tubes and transformers are located on the underside of the hinged top plate. When the top plate is rotated up, the full array of these components is directly viewable and accessible. Likewise, the top plate of the penthouse console and the top plate of the power supply module are hinged to allow direct access to components.
Amplifier Features
Stand Alone: The Guilty Pleasure is a stereo integrated amplifier. An external line stage is unnecessary when the amp is used with mid to high efficiency speakers. This reduces the number of active stages from 7 to 4, resulting in a substantial improvement in clarity, separation of voices, pin-point imaging, and sense of space.
A wide variation exists in the characteristic sound of stand-alone line stages and preamplifiers. The gain stage of the Guilty pleasure serves as a built-in line stage with a neutral voice, providing wonderful sound and simplifying the overall system. While not ideal, external line stages are sometimes found necessary to voice a system; but all things equal, fewer gain stages are better.
Remote Stepped Volume Control: The prototype version of the Guilty Pleasure has a stepped stereo volume control (2 dB per step) with discrete resistors. The product version of the Guilty Pleasure will have a remote stepped volume control (2 dB per step) with discrete resistors. In the remote volume control only two resistors will be active in the volume control circuit at any volume level.
Balance Control: A separate gain control ahead of each channel of the volume control allows the user to lower either of the channels from zero to six dB to achieve system balance. Using a system without control of balance is like driving a car which pulls right or left . . . a constant annoyance.
Stereo/Mono Switch: A stereo/mono switch is located on the front of the penthouse console.
Volume Control Sensitivity Range Switch: A switch is included which allows the user to change the volume control sensitivity by 8 dB to best adjust the volume control range to system sensitivity.
Multiple inputs: Six sets of inputs are provide on the rear panel, along with easily accessible selector switches on the rear panel, one for each channel. The separate selector switches allow the user to play just one channel at a time for diagnostic purposes.
4, 8, and 16 Ohm Taps: Easily accessible binding posts are provided for 4, 8, and 16 ohm speakers. Switches for the power tube current and voltage meters allow the user to check left and right channels or turn the meters off.
Standby Switch: At present the amplifier is set up with an on/off switch to power the heaters and a standby switch to apply power to the plates. Both switches will remain in the product. In operation, the user will be able to use the standby switch to defeat plate power when it is desired to have the amplifier in the standby mode. Cathode life can be extended by switching the standby mode during shut-down until the plate voltage has fallen (as indicated by the plate voltage meter), before turning the amplifier off with the on/off switch..
Backup Vacuum Tubes Provided: Each Guilty Pleasure amplifier will come with a pair and a spare pair of each of the three vacuum tube types, housed in a deluxe padded wood box.
Delayed Startup: The product version of the Guilty Pleasure amplifier will have an automatic timer to apply power to the plates after the heaters are turned on. This will assure that the cathodes are hot before the plates receive power, preventing gradual damage to the cathodes.
Documentation: Lucid documentation will be provided.
Turning The Guilty Pleasure Amplifier Into A Product
I am currently enjoying the design and development activity of turning the Guilty Pleasure stereo integrated amplifier into a no-holds-barred luxury 845 amplifier product. The Guilty Pleasure amplifier comes to the market in a price range consistent with the associated design and development activity, component costs, and labor, putting the product out of the reach of many audiophiles and music lovers. I have tried to keep my products priced to allow many audiophiles own them. However advancing the Guilty Pleasure prototype amplifier to an ultimate level product competitive with the expensive and prestigious Ongaku 211 amplifiers and similar products is labor intensive. I once telephoned a man named Whitney. When he picked up the receiver I gave my name and asked if this was Mr. Whitney. He answered, "Yeah, what's left of him." At 83 years old I have accumulated a wealth of knowledge about things audio, much of which comes to bear on the Guilty Pleasure amplifier. With other products to deliver, I can produce one Guilty Pleasure unit a year. I expect to produce 5 units in the next 5 years.The goal is to have the first commercial Guilty Pleasure amplifier available to the first person on the waiting list in December of 2022.
I would not consider making this amplifier into a limited production product unless I had fallen absolutely in love with it. The amplifier is crying out to become a product. Still crazy after all these years, I look forward to filling a waiting list for 5 Guilty Pleasure amplifiers, one per year, at a price of $49,950 per unit. I have a waiting list ready to accept orders with an initial $1000 deposit. When it is clear that an order is near fulfillment, an additional $4000 will be required to complete the deposit, with the balance due just before shipping. Names will go on the waiting list in the order received. If a purchaser has a change of heart before delivery, or if I am unable to complete the spoken-for amplifier, the deposit will be immediately refunded to the purchaser.
Hear The Guilty Pleasure For Yourself
Call Pete Riggle at 509 582 4548 to make an appointment to hear the Guilty Pleasure amplifier in a system with Altec A7 speakers, Hiraga circuit crossovers built by Pete Riggle, and a 29 foot long subwoofer horn built by Pete and friends. This invitation is open to all, but is particularly important if you or someone you know may be in a position to own one of the few of these amplifiers to be built. I can particularly vouch for the performance of the Guilty Pleasure amplifier driving Altec A5 and A7 loudseakers.
What is Next?
A great deal of product optimization, redesign, component sourcing, fabrication, testing, critical listening, and documentation, are underway to turn the Guilty Pleasure into a prestige audiophile product. It will be a pleasure to take orders to build these wonderful amplifiers for a few very special owners.
All my best to those who have chosen to read about the Guilty Pleasure.
Kind Regards,
Pete
Pete Riggle Audio
2112 S. Olympia Street, Kennewick, WA, USA
shop phone: 509 582 8419 email: peteriggle@msn.com
VTAF™ Trademarked. U.S.Patent No. 7630288.
Website content Copyright © 2021 Pete Riggle Audio, All Rights Reserved.
2112 S. Olympia Street, Kennewick, WA, USA
shop phone: 509 582 8419 email: peteriggle@msn.com
VTAF™ Trademarked. U.S.Patent No. 7630288.
Website content Copyright © 2021 Pete Riggle Audio, All Rights Reserved.