I like the Edcor blue, it has become synonymous with the brand.
Of course, personal design preference and the rest of the amp could require some re-painting.
I saw someone on YT recommending changing the chrome bolts to black as well (could be other colours of your choice too).
(a) Sh**gles is one of the Boomer Scourges (along with Hep-C; man, we were a randy bunch). I believe that there's a vaccine for the Roofing Condition, and of course there's a nearly 100% CURE for Hep-C (which boggles the mind), but of course it costs $$$.
(b) Yet ANOTHER HERETIC in our midsts: "I don't feel like I need to add anything or change to anything else." Be still my heart. Total Eclipse of the Sun.
Can't think of a better "stop-'em in their tracks" endorsement, consequently:
(c) Ordered-up a pair of EH KT88s from the TubeDepot sale, with a couple of hours to spare. Great tip, thanks; they were roughly half the price of the Gold Lions, which is a good number for the Shop Amp.
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I have decided to keep the BLUE, but turn the label to the rear.
Of course, my taste in colours is notoriously poor; I will see a Lexus/BMW/Benz car colour I like, pull along side, and it's being driving by a teenaged drug dealer peeking over the steering wheel.
I blame George Barris, the REAL O.G. George Barris (auto customizer - Wikipedia)
The current Edcor blue is the second edition. Here are two Edcor Blue transformers. One is a couple years old. The other is from 2006. Back then I stated that it was a near match for the "pimp my ride" Cadillac that boomed, rattled and bounced its way through our neighborhood at the time. Apparently other customers had the same reaction so the glowing metallic blue was turned down a bit.
Note that my 2006 vintage transformers spent several years on the chassis of a TSE based 307A amp. The original sparkle and shine has faded a bit. Perhaps some car polish and wax could restore the brilliance. Boom - Bumpa - Bumpa - Boom - Bumpa - Bumpa - Boom......
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I know right? And I'm always tinkering and optimising - being an Engineer by trade, I can't seem to help it. Actually, come to think of it I've been doing that since I was a kid, but at that time the electronics I discombobulated rarely were put back together properly.
So it is surprising, but it is also very liberating not to feel the need here to Tube roll for Shuguangs, Golden Lions or any other super expensive output tubes.
Now, I did have either Sovtek or EH for the rectifier tube (no SS rectification in my SSE), and it sounded harsh compared to a spare Sino unbranded one, so I kept the latter in.
Never tried 'burning in' the EH rectifier but maybe it could mellow out with time. It could be that the Sino one has been used previously, I have no way of knowing precisely although technically I bought them as new.
Hope you didn't miss that the manual solder sucker was successfully used to unsolder two tube sockets
There had to be some pulling with fingers as well as leveraging with a small screwdriver to get it all done, but still, this is supposedly really hard to do.Actually, I also had to do that on my SSE board as I had messed up the orientation of one socket. Stressful at the time but pulled it off (that double-entendre was totally unintentional).
On colours: I used to have repeated mini arguments (not heated) with an ex-girlfriend which went like this:
Me: "This is obviously blue!"
Her: "No it's GREEN!"
Me: (sticking to my blue guns)
Her: (not budging from her green story)
... and on and on
Turns out some women have way more optical receptors responsible for colour detection in their eyes compared to men.
Sometimes their hearing abilities best ours too.
Yep, Edcor labels to come off. I do get why they put the large stickers in - they'd like the brand to be seen in pictures and so on, but I removed them in my build too as I think the blue end bells are sufficiently recognisable now, be it one shade or two of existing colour.
Hi George! Your SSE Triode Tube amp was instrumental in accompanying me while doing my DSD DAC isolation experiments, PSU experiments, my DIY Analogue Modular, and my synth and Soundcraft Mixer hacks.
These days, it's harder to do so because lockdown means remote work and living space being loft-like apart from the bedroom means my wife is working right next to me. Many meetings for her via phone and/or Zoom, so can't have the SSE on during the daytime.
Now... I really want my DAC to have Tube outs, plugging into that KT-88 SSE.
It's becoming obsessive.
I am looking for a way to adapt those PCB-mounted sockets I salvaged so that I can mount them easily on a chassis-like surface. I might end up just epoxying a pair of metal 'L'-lugs onto each of them.
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Best thing about Canadian Engineers (besides being pretty practical & down-to-earth) is that RH pinkie ring y’all get.
IIRC it was originally made from the steel of a collapsed bridge, and you’re to wear it on your right pinkie as a reminder when you put pencil to paper. My generation apparently got the Real Steel, but the story goes that they ran-out, which I suppose means that they can use say 316 stainless now, which would be better....
IIRC it was originally made from the steel of a collapsed bridge, and you’re to wear it on your right pinkie as a reminder when you put pencil to paper. My generation apparently got the Real Steel, but the story goes that they ran-out, which I suppose means that they can use say 316 stainless now, which would be better....
I don't remember but I'm sure I settled on a specific recommended in my thread, maybe this picture helps?
Fairly sure I was asking questions about how to read George's recommendations table somewhere and then I picked a resistor or something like that. The thread is a bit long though.
Fairly sure I was asking questions about how to read George's recommendations table somewhere and then I picked a resistor or something like that. The thread is a bit long though.
I put a 680 ohm cathode resistor in my SSE. I wired a dual gang 5 way switch in parallel with it, one gang for each channel. One position had nothing connected, each other position put a different resistor in parallel with the 680 ohm to raise the cathode current. I tried a bunch of different values with clip leads before soldering anything to the switch. The first two positions gave me two good settings for EL34's, and the last two were for KT88's. I never really liked the 6L6 types, and I built a different amp for 6V6's with a smaller power transformer.
OPT's are some Transcendars I bought about 15 years ago. 3K ohms intended for 300B tubes. I ran the EL34's at 6K by plugging my speakers into the 4 ohm terminals.
For mellow "chick singer with a piano" kind of music, I ran EL34's in triode mode on the lowest current setting (680 ohms by itself), usually with my Yamaha NS10-M studio monitors, or my set of upside down FH-3's.
When I desired to rattle the neighbors with some DSOTM, I hooked up the 15 inch OB Hawthorne Silver Iris speakers, popped in the EH KT88's, and cranked the current switch all the way up. The current through each tube was just over 100 mA. They didn't seem to mind, but the Allied 6K7VG power transformer was far too hot to touch after an hour or so.
I used the same two pair of EH tubes in that amp for about 10 years. For about 2 1/2 years it was connected to my computer and was on whenever the computer was on. I used the same tubes until I packed up everything to move when my engineering career ended in 2014. Sadly the SSE was dropped during the move, and hasn't been used since. The old 2004 vintage Allied (Hammond built) power transformer was still good the last time it was used.
At this point in my life, I don't test my patience by trying to unsolder a PC board tube socket. I just cut each pin in half at the board, remove the socket, and then unsolder each pin one at a time with tweezers.....ditto cheap IC chips. I fail to see the need to use IC sockets when the socket costs more than the chip, unless you KNOW that some chip rolling or reprogramming is going to happen.
OPT's are some Transcendars I bought about 15 years ago. 3K ohms intended for 300B tubes. I ran the EL34's at 6K by plugging my speakers into the 4 ohm terminals.
For mellow "chick singer with a piano" kind of music, I ran EL34's in triode mode on the lowest current setting (680 ohms by itself), usually with my Yamaha NS10-M studio monitors, or my set of upside down FH-3's.
When I desired to rattle the neighbors with some DSOTM, I hooked up the 15 inch OB Hawthorne Silver Iris speakers, popped in the EH KT88's, and cranked the current switch all the way up. The current through each tube was just over 100 mA. They didn't seem to mind, but the Allied 6K7VG power transformer was far too hot to touch after an hour or so.
I used the same two pair of EH tubes in that amp for about 10 years. For about 2 1/2 years it was connected to my computer and was on whenever the computer was on. I used the same tubes until I packed up everything to move when my engineering career ended in 2014. Sadly the SSE was dropped during the move, and hasn't been used since. The old 2004 vintage Allied (Hammond built) power transformer was still good the last time it was used.
At this point in my life, I don't test my patience by trying to unsolder a PC board tube socket. I just cut each pin in half at the board, remove the socket, and then unsolder each pin one at a time with tweezers.....ditto cheap IC chips. I fail to see the need to use IC sockets when the socket costs more than the chip, unless you KNOW that some chip rolling or reprogramming is going to happen.
Judging by this post in my thread, I started with a default of 560. I may have switched to George's value above afterwards. Thing is I don't remember precisely.
The 680 value does sound very familiar too.
God knows how much time I spent troubleshooting my circuit when in fact the culprits were a mechanical mistake + short and then salvaged RCA ports not working. We went over almost every measurement possible until I found this one out.
In the end, well worth it!
Here are some operating point details at that time:
"I would like to try and optimise the cathode resistor value or other values as I used a default one of 560 Ohms for the cathode res.
My overall goal is to optimise for SQ: fast transients and low distortion.
My B+ voltage is (at KT-88 - is that all correct?):
5. Left P3: 417 VDC
6. Right P3: 418 VDC
The OPT used has an impedance of 5K."
The 680 value does sound very familiar too.
God knows how much time I spent troubleshooting my circuit when in fact the culprits were a mechanical mistake + short and then salvaged RCA ports not working. We went over almost every measurement possible until I found this one out.
In the end, well worth it!
Here are some operating point details at that time:
"I would like to try and optimise the cathode resistor value or other values as I used a default one of 560 Ohms for the cathode res.
My overall goal is to optimise for SQ: fast transients and low distortion.
My B+ voltage is (at KT-88 - is that all correct?):
5. Left P3: 417 VDC
6. Right P3: 418 VDC
The OPT used has an impedance of 5K."
I know, I know.
In my case, it is more about not wanting to build an order form and wait, I am a bit stubborn when it comes to that as it messes up my prototyping momentum.
In addition, I have no other tube sockets at hand, so re-using these is the only way. Next, I also do not trust either of the two little PCBs I salvaged: one is with the RCA connectors, and the other one is the Behringer Tube PCB.
Now, let me tell you something about that Behringer PCB...
Did you know they actually put in 24V light bulbs right behind the tubes because as the latter are used in a *very* starved design, they wouldn't appear to glow otherwise?
OK, I'll admit I did at least try to re-use the whole PCB just for testing. Here's what happened: I heard and measured some leakage between input and output!
I traced the circuit and while it doesn't appear too far from (while not being identical to datasheet or common implementations), I couldn't explain the leakage. There's no leakage when measuring the sockets only, nor when measuring the tubes only, so it can only be something on the PCB.
Therefore, on waking up yesterday morning, the solution was to ditch the PCBs altogether and start afresh with the two tubes, two sockets and two RCA pairs of connectors.
Of course, had I failed at extracting the sockets, I would have had to bite the bullet and place an order...
...and wait...
...and wait...
...and wait...
I can hack on the circuits now
Actually, I might try to do a little platform like you did George, to explore a few different connections, e.g. SRPP, Mu-follower, cathode-follower, series or parallel, and some of that SS Current Regulation and MOSFET Source follower.
The owner at my place is an Electrician by trade and he gave me a few Screw Terminal strips. these are quite long strips and have quite a large hole in each segment, enough to put several component legs in each. Very handy!
I nearly bought a cheap audio interface at a second-hand store nearby today because I'm going to hack their SS outputs to oblivion and replace them. Fun right?
I didn't though because I have an old Alesis 4-channel Mixer + audio interface which will become the guinea pig for just that. I think TI discontinued the USB interface/DAC chip because it had an issue with the Analogue and Digital 'GNDs'.
That will do!
I was out briefly because we're going to do a St. Paddy's inside tonight.
So Guinness and Cider it is.
Happy St. Paddy's everyone!
P.S. I also attempted to find new soldering iron tips at the local hardware store because of course, I damaged mine and I cannot find the other tips which are in hiding somewhere. Also of course: the hardware store has a non-adjustable Weller with a tip which isn't removable as far as I could see and they had no separate tips to sell. It was also around $37 CAD. I went to a Dollar store on the other side of the road, and found an iron for $9 CAD, removable tip although the iron isn't adjustable. So I'll get that tip out and move it to my adjustable iron - tadaaaa! No online order and no waiting necessary. Smell the solder!
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I read about that somewhere. My case is a bit different as I graduated from a French Grande Ecole d'Ingenieurs. However, several years back in this Province, they'd put in your way all sorts of roadblocks so that you weren't recognised as an Engineer. This changed after a few years as they made a deal for mutual recognition with the Sarkozy Administration.
No ring in France, only the paper and your name and title entered in a database shared by all recognised institutions.
I don't have a ring but Computer Science is my field - it's actually called something equivalent to 'Systems Engineering, Computer Science specialty'.
Electro Harmonix KT88s at 111.111mA bias
The EH KT88s arrived with a couple of 5AR4s from behind the Iron Curtain. Slapped some UF4077s on the RED HT leads (the “Dynaco” mod; this old SSE board doesn’t have it), changed the Rk to 360 ohms, and plopped all the new thermionics in there.
I had forgotten the nice (indirect heater) slow voltage ramp of the 5AR4/GZ34s.
That’s nice. Plus no arcing, knock wood.
KT88s biased-up right on target: 111.111...milliamperes at 38W dissipation.
Sounds pretty good; the clarity of the lower registers is something I hadn’t heard from this SSE before. Pretty nice for a shop amp, and this with 5K EDCOR “G” opts (the mid-sized ones, ~$45 ea. now IIRC) running in Uktra-Linear. I like me some Ultra Linear; it’s just my thing...
Might swap-in some 5K Transcendars (although they’re in same weight class, so I don’t expect much change) or 3K Transcendars or HANDWOUNDS (!). Generally, I prefer the clarity (ie lower distortion) of the higher load...
What’s the prevailing preference on OPT loading for the KT88s in SE?
I have Joni “Blue” on there now (my reference “girl with guitar” tracks); for GWG music, anyway, I doubt that 3K could sound better.
Mind you, the source is Spotify Premium at 32bit/384K thru an outboard DAC (iFi Zen), which is likely overkill, but eliminates any doubts about the quality and consistency of the source.
Curiously, the ancient Thordarson 390-0-390 200mA PST is running pretty COOL with this set-up, that is, just warm, not hot.
6L6s (~80mA) or 6AV5s (~70mA) with 5U4GYBs would turn the PST into a pizza oven.
Also, the massive KT88 bottles seem to run pretty cool, too.
Maybe I’ll scrounge up the pyrometer and see what’s actually going-on.
The EH KT88s arrived with a couple of 5AR4s from behind the Iron Curtain. Slapped some UF4077s on the RED HT leads (the “Dynaco” mod; this old SSE board doesn’t have it), changed the Rk to 360 ohms, and plopped all the new thermionics in there.
I had forgotten the nice (indirect heater) slow voltage ramp of the 5AR4/GZ34s.
That’s nice. Plus no arcing, knock wood.
KT88s biased-up right on target: 111.111...milliamperes at 38W dissipation.
Sounds pretty good; the clarity of the lower registers is something I hadn’t heard from this SSE before. Pretty nice for a shop amp, and this with 5K EDCOR “G” opts (the mid-sized ones, ~$45 ea. now IIRC) running in Uktra-Linear. I like me some Ultra Linear; it’s just my thing...
Might swap-in some 5K Transcendars (although they’re in same weight class, so I don’t expect much change) or 3K Transcendars or HANDWOUNDS (!). Generally, I prefer the clarity (ie lower distortion) of the higher load...
What’s the prevailing preference on OPT loading for the KT88s in SE?
I have Joni “Blue” on there now (my reference “girl with guitar” tracks); for GWG music, anyway, I doubt that 3K could sound better.
Mind you, the source is Spotify Premium at 32bit/384K thru an outboard DAC (iFi Zen), which is likely overkill, but eliminates any doubts about the quality and consistency of the source.
Curiously, the ancient Thordarson 390-0-390 200mA PST is running pretty COOL with this set-up, that is, just warm, not hot.
6L6s (~80mA) or 6AV5s (~70mA) with 5U4GYBs would turn the PST into a pizza oven.
Also, the massive KT88 bottles seem to run pretty cool, too.
Maybe I’ll scrounge up the pyrometer and see what’s actually going-on.
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Steve Brown and I built the Mullard 5-20 KT-88s Mullard 5-20 KT88 PP blocks! that are now 4-60 back in 2015. If you go to the end of the thread you can read our comments.
I needed some help to complete mine so I visited and found him dissatisfied with the sound, about to convert them to 300B. When he ironed out the bugs in mine and we listened in his system with my GL KT-88s (he was using Sovteks) he shelved his 300B plan and ordered a pair of Gold Lions for himself.
I needed some help to complete mine so I visited and found him dissatisfied with the sound, about to convert them to 300B. When he ironed out the bugs in mine and we listened in his system with my GL KT-88s (he was using Sovteks) he shelved his 300B plan and ordered a pair of Gold Lions for himself.
I recognise that orange TubeDepot logo on those strangely satisfying shaped KT88s
You're on to something: the iFi team and their mastery of Burr-Brown's native DSD chips as well as of the XMOS interfaces, in combination with George's SETs (+ large Edcors + EH KT-88s) is a Holy of Holies. I did a lot of experimentation on the older iFi iDSD Nano, measurements and details being on the old computeraudiophile site, now named audiophilestyle - on a long AC Filtering, Grounding, etc... thread. The thing I had to work on a lot was the isolation of the DAC from the computer USB noise.
I recommend you download some DSD64, 128, 256 tracks online and try them on your iFi Zen, played via any of those:
1. Audirvana if you're on Mac
2. HQ Player if you're on Mac or Win (or Linux?)
3. FooBar (Win) - requires some plugins downloads and configuration
The best audio I ever found on my old DAC was DSD256 through to my SET amp and also using my own AC Filter as well as USB isolation connector and injecting my own low-noise Linear Regulated 5V supply to the DAC.
Nowadays, you probably don't need to do the clean power injection on your own as they probably allow that and internalise the USB isolation... Thorsten's teams are great. They also have John Curl on board now.
The cool thing about high-res PCM/DXD is that you are then able to use very gentle filtering instead of the brick-wall type in the audio chain. You can test a few to see what you prefer.
HQPlayer does all sorts of processing on your server PC, so that the DAC itself does just the DA and less processing. The best configuration here is to use a Network-attached device which is smaller than your PC and thus produces less noise and this streams to your DAC (preferably by I2S).
I used to up-convert even all my PCM to DSD using Korg's Audiogate because that was my sweet-spot for my setup.
Nowadays, use Audirvana or HQPlayer (I think Foobar does it too) to to PCM-to-DSD up-conversion in real-time server-side.
In brief,
Wait till you hear DSD256 from your PC going to iFi Zen, going to your SET Tube amp!
Nothing comes close.
Nothing apart from you being in the same room as the band.
My old configuration summoned the dead, quite literally: you'd think Elvis or Bowie were in the room with you.
P.S.: Of course, you also need some vibration isolation, room treatment, clean power everywhere
You're on to something: the iFi team and their mastery of Burr-Brown's native DSD chips as well as of the XMOS interfaces, in combination with George's SETs (+ large Edcors + EH KT-88s) is a Holy of Holies. I did a lot of experimentation on the older iFi iDSD Nano, measurements and details being on the old computeraudiophile site, now named audiophilestyle - on a long AC Filtering, Grounding, etc... thread. The thing I had to work on a lot was the isolation of the DAC from the computer USB noise.
I recommend you download some DSD64, 128, 256 tracks online and try them on your iFi Zen, played via any of those:
1. Audirvana if you're on Mac
2. HQ Player if you're on Mac or Win (or Linux?)
3. FooBar (Win) - requires some plugins downloads and configuration
The best audio I ever found on my old DAC was DSD256 through to my SET amp and also using my own AC Filter as well as USB isolation connector and injecting my own low-noise Linear Regulated 5V supply to the DAC.
Nowadays, you probably don't need to do the clean power injection on your own as they probably allow that and internalise the USB isolation... Thorsten's teams are great. They also have John Curl on board now.
The cool thing about high-res PCM/DXD is that you are then able to use very gentle filtering instead of the brick-wall type in the audio chain. You can test a few to see what you prefer.
HQPlayer does all sorts of processing on your server PC, so that the DAC itself does just the DA and less processing. The best configuration here is to use a Network-attached device which is smaller than your PC and thus produces less noise and this streams to your DAC (preferably by I2S).
I used to up-convert even all my PCM to DSD using Korg's Audiogate because that was my sweet-spot for my setup.
Nowadays, use Audirvana or HQPlayer (I think Foobar does it too) to to PCM-to-DSD up-conversion in real-time server-side.
In brief,
Wait till you hear DSD256 from your PC going to iFi Zen, going to your SET Tube amp!
Nothing comes close.
Nothing apart from you being in the same room as the band.
My old configuration summoned the dead, quite literally: you'd think Elvis or Bowie were in the room with you.
P.S.: Of course, you also need some vibration isolation, room treatment, clean power everywhere
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I had read a lot about how SETs would be lacking in the bass department, but when I tried my SSE, despite a not-so-efficient pair of Totem Mites, I didn't find it to be the case with the big Edcors and the EH KT88s.
Maybe being in a smaller room helps as is not having the reproduction of the concert hall with orchestra experience as end goal.
For the afficionados of the latter type, there may be some difference.
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