Gang,
Has anyone tried these Stradi tubes?
https://www.straditube.com/
They have a really good selection of tubes I like. RE604, PX4 and some high mu DHT. Not that the RS241/242 are equivalent to Telefunken. When I asked about Class A2 they said they never tried it.
Their 2A3 looks interesting even if you use it at normal power 15W.
Thanks,
Gordon
Has anyone tried these Stradi tubes?
https://www.straditube.com/
They have a really good selection of tubes I like. RE604, PX4 and some high mu DHT. Not that the RS241/242 are equivalent to Telefunken. When I asked about Class A2 they said they never tried it.
Their 2A3 looks interesting even if you use it at normal power 15W.
Thanks,
Gordon
Gordon and Gang,
Take a look at the Stradi 3A 110B.
1. There is a grid wire Above the top of the plate.
2. There is a grid wire Below the bottom of the plate.
Note: All of my National 45 tubes have grid wires above and below, versus their plate's tops and bottoms.
Therefore, the 'diode action' of a 'filament and plate' Without the grid wire between them, is eliminated!
Just saying that this extra grid wire 'factor' might be one of the characteristics that makes the 45 such a good sounding tube.
Your opinions, please . . .
Thanks!
Take a look at the Stradi 3A 110B.
1. There is a grid wire Above the top of the plate.
2. There is a grid wire Below the bottom of the plate.
Note: All of my National 45 tubes have grid wires above and below, versus their plate's tops and bottoms.
Therefore, the 'diode action' of a 'filament and plate' Without the grid wire between them, is eliminated!
Just saying that this extra grid wire 'factor' might be one of the characteristics that makes the 45 such a good sounding tube.
Your opinions, please . . .
Thanks!
They go on about the frame grid, but really having it above and below the plate structure wouldn't really have any effect I think.
They do go on and on about their frame grid being less microphonic.
My question is that I have never heard of these guys and my user base is large and usually some tube nerd is proding me about new tubes.
I did get on them for the RS241/242 not being true Tele types. I said just rename them because I sold a couple of amps that are Class A/A2 with RS241 and I am pretty sure these would arc over or lock up when hitting A2.
The 2A3 looks interesting, but it's not my fav tube unless you have TungSol single plates. Otherwise most of the new ones are just 300B with the filament folded in half. This one is just a Eb with a different filament which would probably sound great with AC heaters. Problem is most of my users will want an amp that has NOS tube capabilities. Which fine you could work up a 15W 2A3 bias and have it work. But sonically it would be very different.
BTW the 45 is the best sounding tube ever made. The NOS ones are just the best. Actually the amp I am making now.
Thanks,
Gordon
They do go on and on about their frame grid being less microphonic.
My question is that I have never heard of these guys and my user base is large and usually some tube nerd is proding me about new tubes.
I did get on them for the RS241/242 not being true Tele types. I said just rename them because I sold a couple of amps that are Class A/A2 with RS241 and I am pretty sure these would arc over or lock up when hitting A2.
The 2A3 looks interesting, but it's not my fav tube unless you have TungSol single plates. Otherwise most of the new ones are just 300B with the filament folded in half. This one is just a Eb with a different filament which would probably sound great with AC heaters. Problem is most of my users will want an amp that has NOS tube capabilities. Which fine you could work up a 15W 2A3 bias and have it work. But sonically it would be very different.
BTW the 45 is the best sounding tube ever made. The NOS ones are just the best. Actually the amp I am making now.
Thanks,
Gordon
Stumbled across the Stradi site last week.
https://www.straditube.com/index.html
Curious to hear if there are any user experiences ?
https://www.straditube.com/index.html
Curious to hear if there are any user experiences ?
It's interesting to see Stradi talking about optimising for DHT preamps. If it means that they have successfully reduced the microphony in this range of DHTs, it's good for the sound in all applications.
It's a pleasant surprise to see their version of the STC 3A/109 too. Splendid tweeter driver or preamp valve.
It's a pleasant surprise to see their version of the STC 3A/109 too. Splendid tweeter driver or preamp valve.
The classic 3/2 power triode model is based on infinite parallel planes, and smaller, finite, surfaces add impurities. Maybe a decent analogy to "overhung" grids might be overhung voice coils, in the sense that they minimize edge fringing effects, but not in the sense that they sacrifice conversion efficiency (because the grid doesn't consume power, and is unipotential anyway).
Very cool to see these craft valve businesses keep appearing. Coming from Korea, expectations should be high.
All good fortune,
Chris
Build an underhung voice coil, and the good and bad tradeoffs are well known.
Build an underhung triode grid, and I suspect that part of the tube acts more like a diode, than a triode.
You essentially get a triode in parallel with a diode.
The degree of the effect depends on the area that the underhung grid covers, versus the area the grid does not cover . . . that is the diode area.
The 45 tubes I have seen all have overhung grids.
Build an underhung triode grid, and I suspect that part of the tube acts more like a diode, than a triode.
You essentially get a triode in parallel with a diode.
The degree of the effect depends on the area that the underhung grid covers, versus the area the grid does not cover . . . that is the diode area.
The 45 tubes I have seen all have overhung grids.
What irks me most with these tube companies is when they say they optimized the original design and then when you look at the specs they have optimized out some of the most elegant things the original had.
Like grid to plate spacing... the closer the higher the gain, lower Rp but then they do mesh and on power up with a directly heated rectifier which heats quickly the damn thing arcs over. Then they change the design to fix that with gold grid and increase the cost 3x.
When the 300B was redone by Charlie the vacuum equipment on the circular workstations were crap so he had to have some re-engineer that. That increased (decreased???) the vacuum by 30%. This dropped the Rp and gave the tube better range.
In the end lets hope they sound and work better than some of the NOS tubes I have.
Thanks,
Gordon
Like grid to plate spacing... the closer the higher the gain, lower Rp but then they do mesh and on power up with a directly heated rectifier which heats quickly the damn thing arcs over. Then they change the design to fix that with gold grid and increase the cost 3x.
When the 300B was redone by Charlie the vacuum equipment on the circular workstations were crap so he had to have some re-engineer that. That increased (decreased???) the vacuum by 30%. This dropped the Rp and gave the tube better range.
In the end lets hope they sound and work better than some of the NOS tubes I have.
Thanks,
Gordon
Gordon,
I am so glad that you and countless others in the commercial tube business, let so many magazines publish your schematics, etc.
Your "Baby Ongaku" built and written about by Frank Reps in Sound Practices is one example.
I am quite sure that many diy'ers built it, or were at least inspired to design and build their own.
The Bugle was one of the other examples.
You can put a number on commercial business success.
But it is impossible to measure the impact of your and other's actions that lead to so much fun, and listening joy to others.
Thanks to all of you!
"It is a Mean thing to say that Karl Friedrich Gauss was an Average man, who was Centered on his Gaussian Curve."
I am so glad that you and countless others in the commercial tube business, let so many magazines publish your schematics, etc.
Your "Baby Ongaku" built and written about by Frank Reps in Sound Practices is one example.
I am quite sure that many diy'ers built it, or were at least inspired to design and build their own.
The Bugle was one of the other examples.
You can put a number on commercial business success.
But it is impossible to measure the impact of your and other's actions that lead to so much fun, and listening joy to others.
Thanks to all of you!
"It is a Mean thing to say that Karl Friedrich Gauss was an Average man, who was Centered on his Gaussian Curve."
Thanks!
Its not fun unless you let people in. I do free design work for a ton of companies big and small.
G.
Its not fun unless you let people in. I do free design work for a ton of companies big and small.
G.
HI I got a pair of RE604 from Strady, great service and very good packing , they look very well build too
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Do you have any Tele RE604 to compare them too? In my communications with them they seem to want to better the originals. Which has been so so in the case of KR and EML. So I have no problem if they are better and at least have the same specs as the original and not 50% more filament and less wattage or drastic other specs. Look at the Psvane WE275 it's no were near the specs of a WE 275, they didn't even get the filament correct!
How about a 6L6 Stradi?
6550, 12ax7?
Or are we only marketing to the folks that spend twice as much for half an amplifier?
6550, 12ax7?
Or are we only marketing to the folks that spend twice as much for half an amplifier?
I think they are only interested in making directly heated triodes.
But why 6L6 it was a mistake RCA made early on because of Fender. Basically Langford and Smith worked with Fender to make amps based on the 6V6. Because RCA wanted the tube biz from Fender and they were under contract. But when Fender went into production the B+ was crazy high in some cases 400V. This lead to failures, which then Fender went to other companies for the 6V6. RCA quickly developed the 6L6 and tried to sell that to Fender but nobody there liked the design.
Now WE has all the tube making equipment to make 6L6, 6550 and all the 12Axxx tubes now. Charlie has had that for years. But bringing up that kind of production is a lot of work and requires almost 24/7 working to keep it going. He talked to me about this last summer sometime. No word on when or if it is going to happen.
But why 6L6 it was a mistake RCA made early on because of Fender. Basically Langford and Smith worked with Fender to make amps based on the 6V6. Because RCA wanted the tube biz from Fender and they were under contract. But when Fender went into production the B+ was crazy high in some cases 400V. This lead to failures, which then Fender went to other companies for the 6V6. RCA quickly developed the 6L6 and tried to sell that to Fender but nobody there liked the design.
Now WE has all the tube making equipment to make 6L6, 6550 and all the 12Axxx tubes now. Charlie has had that for years. But bringing up that kind of production is a lot of work and requires almost 24/7 working to keep it going. He talked to me about this last summer sometime. No word on when or if it is going to happen.
RE604 Telefunken spice model and RE604 stradi model.
.
.
.
Code:
**** Composite DHT *****************************************
* Created on 04/19/2025 21:49 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file: TFK
* Data source link:
*----------------------------------------------------------------------------------
.SUBCKT RE604_DHT 1 2 3 4 ; P G K1 K2
+ PARAMS: CCG=6P CGP=8.2P CCP=5P RFIL=6.15
+ MU=3.78 KG1=2374.6 KP=61.89 KVB=1472.7 VCT=0.2 EX=1.304 RGI=2000
* Vp_MAX=900 Ip_MAX=200 Vg_step=10 Vg_start=10 Vg_count=16
* Rp=6000 Vg_ac=45 P_max=12 Vg_qui=-45 Vp_qui=245
* X_MIN=61 Y_MIN=40 X_SIZE=890 Y_SIZE=519 FSZ_X=1765 FSZ_Y=653 XYGrid=true
* showLoadLine=y showIp=y isDHT=y isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=y
*----------------------------------------------------------------------------------
RFIL_LEFT 3 31 {RFIL/4}
RFIL_RIGHT 4 41 {RFIL/4}
RFIL_MIDDLE1 31 34 {RFIL/4}
RFIL_MIDDLE2 34 41 {RFIL/4}
E11 32 0 VALUE={V(1,31)/KP*LOG(1+EXP(KP*(1/MU+V(2,31)/SQRT(KVB+V(1,31)*V(1,31)))))}
E12 42 0 VALUE={V(1,41)/KP*LOG(1+EXP(KP*(1/MU+V(2,41)/SQRT(KVB+V(1,41)*V(1,41)))))}
RE11 32 0 1G
RE12 42 0 1G
G11 1 31 VALUE={(PWR(V(32),EX)+PWRS(V(32),EX))/(2*KG1)}
G12 1 41 VALUE={(PWR(V(42),EX)+PWRS(V(42),EX))/(2*KG1)}
RCP1 1 34 1G
C1 2 34 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 34 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; FOR GRID CURRENT
D4 6 4 DX ; FOR GRID CURRENT
RG1 2 5 {2*RGI} ; FOR GRID CURRENT
RG2 2 6 {2*RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS RE604_DHT
*$
**** ******************************************
* Created on 04/19/2025 21:50 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file: /Users/zoran/Desktop/Model_Paint_Tools/Graph/
* Data source link:
*----------------------------------------------------------------------------------
.SUBCKT RE604 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=6P CGP=8.2P CCP=5P RGI=2000
+ MU=3.78 KG1=2374.6 KP=61.89 KVB=1472.7 VCT=0.2 EX=1.304
* Vp_MAX=900 Ip_MAX=200 Vg_step=10 Vg_start=10 Vg_count=16
* Rp=6000 Vg_ac=45 P_max=12 Vg_qui=-45 Vp_qui=245
* X_MIN=61 Y_MIN=40 X_SIZE=890 Y_SIZE=519 FSZ_X=1765 FSZ_Y=653 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=y
*----------------------------------------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G ; TO AVOID FLOATING NODES
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; POSITIVE GRID CURRENT
R1 2 5 {RGI} ; POSITIVE GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS RE604
*$.
Code:
**** ******************************************
* Created on 04/20/2025 08:26 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file:
* Data source link:
*----------------------------------------------------------------------------------
.SUBCKT RE604_stradi 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=3P CGP=1.4P CCP=1.9P RGI=2000
+ MU=4 KG1=4392.6 KP=17.17 KVB=100 VCT=-4 EX=1.46
*----------------------------------------------------------------------------------
* Vp_MAX=350 Ip_MAX=100 Vg_step=10 Vg_start=10 Vg_count=10
* Rp=4000 Vg_ac=40 P_max=12 Vg_qui=-40 Vp_qui=250
* X_MIN=81 Y_MIN=25 X_SIZE=468 Y_SIZE=500 FSZ_X=1363 FSZ_Y=641 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=y
*----------------------------------------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G ; TO AVOID FLOATING NODES
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; POSITIVE GRID CURRENT
R1 2 5 {RGI} ; POSITIVE GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS RE604_stradi
*$Yes, I did compare with the RE-604, Philips D404, Mazda 601 and Valvo LK460... It sounds more like the Valvo than RE604, not bad just diferent
I think RE604 its hard to beat
Hi
I forgot to add D404 model. Based on original datasheet anode chrs. graph.
2 same spice models for D404, one DHT another plain triode...
.
All tubes RE604 TFK, RE604 Stradi, D404 are different...
.
.
I forgot to add D404 model. Based on original datasheet anode chrs. graph.
2 same spice models for D404, one DHT another plain triode...
.
All tubes RE604 TFK, RE604 Stradi, D404 are different...
.
.
Code:
**** Composite DHT *****************************************
* Created on 10/23/2024 09:29 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file: D404 datasheet
* Data source link:
*
* Vf=4V If=0.65 A acc.
* Vamax=250V Iamax=60mA Pamax=10W
* Ia normal = 40mA
* Starting point of grid current = -2V
* Max resistance in grid circuit Rg = 0.6meg/1meg
* Equivalent to RE604 P460 PX460 ...
*
*----------------------------------------------------------------------------------
.SUBCKT D404_DHT 1 2 3 4 ; P G K1 K2
+ PARAMS: CCG=5.2P CGP=7P CCP=5.7P RFIL=6.15
+ MU=4.388 KG1=2790 KP=42 KVB=300 VCT=0.8 EX=1.33 RGI=2000
* Vp_MAX=600 Ip_MAX=100 Vg_step=4 Vg_start=8 Vg_count=28
* Rp=7500 Vg_ac=38.5 P_max=10 Vg_qui=-38.5 Vp_qui=250
* X_MIN=80 Y_MIN=53 X_SIZE=987 Y_SIZE=659 FSZ_X=1865 FSZ_Y=866 XYGrid=true
* showLoadLine=y showIp=y isDHT=y isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=y
*----------------------------------------------------------------------------------
RFIL_LEFT 3 31 {RFIL/4}
RFIL_RIGHT 4 41 {RFIL/4}
RFIL_MIDDLE1 31 34 {RFIL/4}
RFIL_MIDDLE2 34 41 {RFIL/4}
E11 32 0 VALUE={V(1,31)/KP*LOG(1+EXP(KP*(1/MU+V(2,31)/SQRT(KVB+V(1,31)*V(1,31)))))}
E12 42 0 VALUE={V(1,41)/KP*LOG(1+EXP(KP*(1/MU+V(2,41)/SQRT(KVB+V(1,41)*V(1,41)))))}
RE11 32 0 1G
RE12 42 0 1G
G11 1 31 VALUE={(PWR(V(32),EX)+PWRS(V(32),EX))/(2*KG1)}
G12 1 41 VALUE={(PWR(V(42),EX)+PWRS(V(42),EX))/(2*KG1)}
RCP1 1 34 1G
C1 2 34 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 34 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; FOR GRID CURRENT
D4 6 4 DX ; FOR GRID CURRENT
RG1 2 5 {2*RGI} ; FOR GRID CURRENT
RG2 2 6 {2*RGI} ; FOR GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS D404_DHT
*$
**********************************************
* Created on 10/23/2024 09:29 using paint_kit.jar 3.1
* www.dmitrynizh.com/tubeparams_image.htm
* Plate Curves image file: /Users/zoran/Desktop/Model_Paint_Tools/Graph/
* Data source link:
*
* Vf=4V If=0.65 A acc.
* Vamax=250V Iamax=60mA Pamax=10W
* Ia normal = 40mA
* Starting point of grid current = -2V
* Max resistance in grid circuit Rg = 0.6meg/1meg
* Equivalent to RE604 P460 PX460 ...
*
*----------------------------------------------------------------------------------
.SUBCKT D404 1 2 3 ; Plate Grid Cathode
+ PARAMS: CCG=5.2P CGP=7P CCP=5.7P RGI=2000
+ MU=4.388 KG1=2790 KP=42 KVB=300 VCT=0.8 EX=1.33
*----------------------------------------------------------------------------------
* Vp_MAX=600 Ip_MAX=100 Vg_step=4 Vg_start=8 Vg_count=28
* Rp=7500 Vg_ac=38.5 P_max=10 Vg_qui=-38.5 Vp_qui=250
* X_MIN=80 Y_MIN=53 X_SIZE=987 Y_SIZE=659 FSZ_X=1865 FSZ_Y=866 XYGrid=true
* showLoadLine=y showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=y
* showIg1=n gridLevel2=n isInputSnapped=n
* XYProjections=y harmonicPlot=y dissipPlot=y
*----------------------------------------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G ; TO AVOID FLOATING NODES
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; POSITIVE GRID CURRENT
R1 2 5 {RGI} ; POSITIVE GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS D404
*$