So what is the other amplifier design? What makes it cheaper?
Dave, I counted 27 caps... of the electrolytic types...
Beyond the iron, there's nothing very expensive inside the chassis. Tango outputs are pricey and the rest of the iron could cost a bit too.... but outside of the OPTs there doesn't appear to be any brand name on the rest. It's unclear what the special rectifiers cost, but silicon shouldn't be that expensive regardless. 811 tubes are still available and Cetron still makes new (IIRC), hence they're not that expensive (compared to WE300Bs).
Either way, transmitting tubes always have the mystical look and bright glow... I prefer the 808 with it's large glass upper globe and cherry red plate when running in CCS mode. Here's one from Valve's World, also a Shishido circuit.
http://www2u.biglobe.ne.jp/~tossie/Y808-E.html
I think a well done IT coupled amp can work well... but as with everything, it's a trade-off. When you have Class A2 operation (grid is driven positive with respect to the cathode) it draws current and typical RC coupling simply doesn't work. There's also Dynamic coupling using a driver tube that sources it current flow via the output tube grid, but the IT works best here.
Regards, KM
Dave, I counted 27 caps... of the electrolytic types...
Beyond the iron, there's nothing very expensive inside the chassis. Tango outputs are pricey and the rest of the iron could cost a bit too.... but outside of the OPTs there doesn't appear to be any brand name on the rest. It's unclear what the special rectifiers cost, but silicon shouldn't be that expensive regardless. 811 tubes are still available and Cetron still makes new (IIRC), hence they're not that expensive (compared to WE300Bs).
Either way, transmitting tubes always have the mystical look and bright glow... I prefer the 808 with it's large glass upper globe and cherry red plate when running in CCS mode. Here's one from Valve's World, also a Shishido circuit.
http://www2u.biglobe.ne.jp/~tossie/Y808-E.html
I think a well done IT coupled amp can work well... but as with everything, it's a trade-off. When you have Class A2 operation (grid is driven positive with respect to the cathode) it draws current and typical RC coupling simply doesn't work. There's also Dynamic coupling using a driver tube that sources it current flow via the output tube grid, but the IT works best here.
Regards, KM
planet10 said:
One of these days i'd like to do an amp with these 810s
Just cause they look so cool... they make an 845 look like a pip-squeak
dave
True, but once you've held an 831 in your hands, even the 810 seems like a baby!
It's in the TT-3 manual... over 17" long with a plate rating of 400 watts. It can scare small children before you light it up.
Regards, KM
kmaier said:
Josh Stippich's GM100 amps at VSAC2003 were pretty damn scary too (and you could smell the ozone down the hall)
http://www.nutshellhifi.com/VSAC2003-2.html
Black Gates from the Joe Net
A post from the Joe Net this week...
"All,
I don't know about the electros, but all the Mundorf film caps I have
used (several) have been made by SCR. One can often get the same cap
under another brand (in my case, Solen) for 15% or so less. For my
breadboards i use the Solens; for client pieces, I spring the two
clams for the cute black jacket and gold printing, and associated
cachet.
Electrolytics, I tested Panasonic TSHA and TSHB against Black Gates
and Cerafines, and they were sonically indistinguishable from the BGs
and slightly superior to the Cerafines (which sounded a little 'white'
in comparison). This is in power supply duty. In the signal path,
they would presumably be used as cathode R bypass; all of which sound
like Doggy Doo to me. I eschews 'em.
I have pontificated. Please forgive.
Aloha,
Poinz"
I have no love of lytics or BG or other wise...
A post from the Joe Net this week...
"All,
I don't know about the electros, but all the Mundorf film caps I have
used (several) have been made by SCR. One can often get the same cap
under another brand (in my case, Solen) for 15% or so less. For my
breadboards i use the Solens; for client pieces, I spring the two
clams for the cute black jacket and gold printing, and associated
cachet.
Electrolytics, I tested Panasonic TSHA and TSHB against Black Gates
and Cerafines, and they were sonically indistinguishable from the BGs
and slightly superior to the Cerafines (which sounded a little 'white'
in comparison). This is in power supply duty. In the signal path,
they would presumably be used as cathode R bypass; all of which sound
like Doggy Doo to me. I eschews 'em.
I have pontificated. Please forgive.
Aloha,
Poinz"
I have no love of lytics or BG or other wise...
A few corrections and amplifications:
The RMS of the Feastrex prototype amp shown above is about 15WPC, not 28. (I simply misread what Feastrex's president had posted to his blog.)
The electrolytic capacitors shown are primarily for use with the Degawa rectification modules, which experience virtually no output spiking to begin with.
The bias is +26V so it is pretty much an all-time A2 operation amplifier.
The wires that are not attached in the photo are those used for NFB, and the sound is being repeatedly tested with them alternately attached and removed.
There are no coupling capacitors, and the cathode bias capacitors are Black Gates. The B voltage final block capacitors (mounted atop the chassis) are both film caps.
-- Chris
The RMS of the Feastrex prototype amp shown above is about 15WPC, not 28. (I simply misread what Feastrex's president had posted to his blog.)
The electrolytic capacitors shown are primarily for use with the Degawa rectification modules, which experience virtually no output spiking to begin with.
The bias is +26V so it is pretty much an all-time A2 operation amplifier.
The wires that are not attached in the photo are those used for NFB, and the sound is being repeatedly tested with them alternately attached and removed.
There are no coupling capacitors, and the cathode bias capacitors are Black Gates. The B voltage final block capacitors (mounted atop the chassis) are both film caps.
-- Chris
Mike,
No idea how the 808 amp sounds... but there are really beautifully done pieces on this site. I especially like the 3C24 amp and the 4E27 amp is killer.... and a good 20-watts output. My collection of transmitter tubes actually includes 808s, 3C24s and a 4E27s... all new, so the temptation to build an amp based on these is growing.
Phil (aka Poinz),
Couldn't agree more on the caps.... I won't use electrolytics anywhere. Unfortunately I'm being forced to for my latest stuff... both the WE300B and NOS single-plate 2A3 triodes won't get quiet without DC filaments... a real bummer. It seems there's only a handful of manufacturers actually making the caps. I use Axon High-Volt caps in the power supply (which are no longer made), the Axon TrueCap for all cathode bypass and the Axon foil and film for coupling. Pretty sure these are made by SCR or Solen as well. Still, excellent capacitors.
Chris,
Thanks for the updates/corrections on the amp. Power output is more believable at 15 watts. Still, a ton of electrolytics underneath and they won't have anywhere near the lifespan of any of the Feastrex drivers. As for biasing, Class A2 is an interesting mode but at +26 volts, you will have swings into the negative region once the power increases. This will certainly affect the driver stage is two ways, first, you cross between pushing power when in positive bias, as the grid is drawing current, and (theoretically) not pushing any power when the grid is negative. It's a crossover point. Second, when the grid is positive you're drawing current thru the secondary winding and contributing additional magnetic field changes in the IT.
While many people are very keen on direct-coupled designs, they create other problems, especially in SE designs. Traditionally, SE designs are lower power and have to cope with large magnetic fields in the OPT. Normal operation swings the magnetic field in the OPT to saturation on the positive swing (output tube grid) and into field collapse on the negative swing. Coupling to DC and using massive cathode bypass caps to get the F3 point down below 0.5Hz or whatever doesn't really help with realities of source material. As an example, vinyl playback becomes a problem... things like slight record warp can easily push the above condition on an SE amplifier and things fall apart at moderate listening levels. I prefer to limit the low-frequency extension to help minimize such effects. Of course, that's my $0.02 and others may feel very differently... which is fine.
Regards, KM
No idea how the 808 amp sounds... but there are really beautifully done pieces on this site. I especially like the 3C24 amp and the 4E27 amp is killer.... and a good 20-watts output. My collection of transmitter tubes actually includes 808s, 3C24s and a 4E27s... all new, so the temptation to build an amp based on these is growing.
Phil (aka Poinz),
Couldn't agree more on the caps.... I won't use electrolytics anywhere. Unfortunately I'm being forced to for my latest stuff... both the WE300B and NOS single-plate 2A3 triodes won't get quiet without DC filaments... a real bummer. It seems there's only a handful of manufacturers actually making the caps. I use Axon High-Volt caps in the power supply (which are no longer made), the Axon TrueCap for all cathode bypass and the Axon foil and film for coupling. Pretty sure these are made by SCR or Solen as well. Still, excellent capacitors.
Chris,
Thanks for the updates/corrections on the amp. Power output is more believable at 15 watts. Still, a ton of electrolytics underneath and they won't have anywhere near the lifespan of any of the Feastrex drivers. As for biasing, Class A2 is an interesting mode but at +26 volts, you will have swings into the negative region once the power increases. This will certainly affect the driver stage is two ways, first, you cross between pushing power when in positive bias, as the grid is drawing current, and (theoretically) not pushing any power when the grid is negative. It's a crossover point. Second, when the grid is positive you're drawing current thru the secondary winding and contributing additional magnetic field changes in the IT.
While many people are very keen on direct-coupled designs, they create other problems, especially in SE designs. Traditionally, SE designs are lower power and have to cope with large magnetic fields in the OPT. Normal operation swings the magnetic field in the OPT to saturation on the positive swing (output tube grid) and into field collapse on the negative swing. Coupling to DC and using massive cathode bypass caps to get the F3 point down below 0.5Hz or whatever doesn't really help with realities of source material. As an example, vinyl playback becomes a problem... things like slight record warp can easily push the above condition on an SE amplifier and things fall apart at moderate listening levels. I prefer to limit the low-frequency extension to help minimize such effects. Of course, that's my $0.02 and others may feel very differently... which is fine.
Regards, KM
Cal Weldon said:Now Chris
"now they say that cat Shaft is a bad >>>> "
" shut your mouth"
"I'm talkin 'bout Shaft"
"we can diggit"
Cal, I didn't think it was that offensive, but as George Carlin might have said "like beauty, scatology is in the eye/ears of the beholder"
now, back to your regular programming - that's still a scary picture
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.