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 NEW  Matt presents bias and operation data for the 6V6 tube in SE operation - 6V6 Single-Ended (SE) Ultra Linear (UL) Bias Optimization.

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PostPosted: 28 Aug 2011, 20:41 
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Isophon wrote:
Isophon wrote:
Suncalc wrote:
Unfortunately I don't know of any 6SN7/807 (or 6SN7/1625) SE designs floating around on the net at all. All of the designs of which I know are for 807 PP modulators and audio stages.


My only issue is some 120Hz hum (20mV) so I will need to add a B+ ripple filter as per P Millett web site shown in his engineer's amplifier using the sweep tube.

The amp. sounds quite good while the dissipation on the 807 is close to its limit at 90%...


Well, I was getting annoyed with the 120Hz hum so I added tonight the B+ ripple filter..works like a charm. Ripple on each speaker output went down from 20mV to 3mV. I was sure the amp wasn't on it that quiet :up:
No need for bulky coil and at least the power supply does not sag. I have attached the updated schematics, looks like the B+ filter takes about 10V to work so the B+ going to the OPT's is slightly lower. I'm thrilled..hope the schematics can be useful to someone willing to use these beautiful 807 in a UL set-up :lildevil:

Regards,
Eric aka Isophon

Good work. Suncalc design an 807 for me. Did you see the schematic? What are your thoughts?

_________________
Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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PostPosted: 28 Aug 2011, 21:16 
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Joined: 20 Sep 2008, 19:49
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Location: Montreal, Canada
mwhouston wrote:
Good work. Suncalc design an 807 for me. Did you see the schematic? What are your thoughts?


Hi,

From reading this thread I'm not sure if you did build the amp from Suncalc because you had some friends willing to pay for you to build some amps :mrgreen:

His design looks very good but I kind of like CCS to drive the triode driver and they are so easy and cheap to implement. Maybe 4mA is on the low side since I read (I do not have enough experience yet) at many places that you need at least 6mA to deal with the 807 Miller effect.
I previously used the 6N1P-EV in a 12AV5GA SET amp (2.5W..my all time fav.) and the driver current was set to 9-10mA.
With the big 25W OPT I'm sure it sounds awesome. I really like mine, acoustic guitar gives me a permanent smile, gotta love DIY :mrgreen:

Going off topic for 1-2 lines : So far I've build 4 tube amps which are all SE..or SET, this is the first UL amp that I enjoy. Low power amps are excellent, I've got 2.5W all the way up to about 6W (WOW !)
My next one will either be a 6BQ5 PP or a 807 PP. (I already bought the OPT + tubes for these 2 amps...)

Back to topic..I really enjoy the 807 as per my schematic but could not stand the RH807 which I tried to improved for over 3-4 months (pentode driven, VR tube for screen, you name it...)

When properly used, the 807 can really sing !!

Regards,
Iso

_________________
DIY SS Amp : LM3875 GC | TA2024 | TA2020 (AMP-6) | TA2022 | Amp Camp Amp | JLH
DIY Tube Amp : RH84 SE | 6V6 SET | 13FD7 SET (Chinook) | 807 UL SE | 6BQ5 Class A PP UL | 6LR8 SE
DIY Spkrs : Cyburgs Needle | MLTL (FE206E) | CSS EL70 BR | Open Baffle (Alpha 15A + FE206En) (in process...)
DIY Pre-Amp : MooseFET.
To come : MLTL (CSS enabled EL70) + more tube amp...


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PostPosted: 28 Aug 2011, 22:05 
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Isophon wrote:
mwhouston wrote:
Good work. Suncalc design an 807 for me. Did you see the schematic? What are your thoughts?


Hi,

From reading this thread I'm not sure if you did build the amp from Suncalc because you had some friends willing to pay for you to build some amps :mrgreen:

His design looks very good but I kind of like CCS to drive the triode driver and they are so easy and cheap to implement. Maybe 4mA is on the low side since I read (I do not have enough experience yet) at many places that you need at least 6mA to deal with the 807 Miller effect.
I previously used the 6N1P-EV in a 12AV5GA SET amp (2.5W..my all time fav.) and the driver current was set to 9-10mA.
With the big 25W OPT I'm sure it sounds awesome. I really like mine, acoustic guitar gives me a permanent smile, gotta love DIY :mrgreen:

Going off topic for 1-2 lines : So far I've build 4 tube amps which are all SE..or SET, this is the first UL amp that I enjoy. Low power amps are excellent, I've got 2.5W all the way up to about 6W (WOW !)
My next one will either be a 6BQ5 PP or a 807 PP. (I already bought the OPT + tubes for these 2 amps...)

Back to topic..I really enjoy the 807 as per my schematic but could not stand the RH807 which I tried to improved for over 3-4 months (pentode driven, VR tube for screen, you name it...)

When properly used, the 807 can really sing !!

Regards,
Iso

You are right I am yet to build Suncalcs 807 design. It will be my next major project. I built the 300BSE Silver Dragon which took a year and now just catching on smaller projects. You have got me excited by what you are saying about the 807 tubes. I finish my current job at the end of this week and intend to have a few weeks off all work. So an excellent time to get the 807 amp finsihed. Thanks for your good comments.

_________________
Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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PostPosted: 29 Aug 2011, 07:51 
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Joined: 11 Aug 2009, 15:04
Posts: 10
Hi
The pseudo L or gyrator, often gives more problems than solutions.
Good 6n1p-ev wiht CCS, 9 10mA really is good sound this point (SE KT88 Alex Genaro...), also up to 12ma wihtout problems a nice soud.
807 need little more V signal


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PostPosted: 29 Aug 2011, 09:46 
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Joined: 18 Jun 2010, 12:46
Posts: 284
Location: Northern VA
When you CCS load your 6N1P, try using and LED on the cathode for the bias.


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PostPosted: 29 Aug 2011, 10:02 
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Joined: 11 Aug 2009, 15:04
Posts: 10
Very well!
Biasing LED is the next step, fine!
(see development of the SE KT88 6N1P in this forum)


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PostPosted: 07 Oct 2011, 21:46 
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Location: US Pacific Northwest
Since doing the design for this amp I have developed a 6SL7/807 (or 12SL7/1625) triode strapped design for which I just ordered all the Iron from Edcor. It's lower power, 3.7W vs 6.3W (-2.3dB), with a very similar Ds, 1.41%/W vs 1.35%/W. I'm hoping for something special out of the triode strapped mode of operation.

So I guess now the race is on. Of course, I'm still waiting for the Edcor order and probably will be for another 4 weeks or so. When I get closer to starting it I'll split off a separate thread. I look forward to comparing them (at least virtually). Too bad the amps will physically be on separate sides of the globe. :(

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Matt
It's all about the Glass!
http://www.CascadeTubes.com
Cascade Tubes Blog


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PostPosted: 08 Oct 2011, 07:30 
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Location: Australia
Matt: If YOU think MY ATS25 is not going to exist or happen you R wrong. I have to admit there has been a lot of other projects in the way but the ATS25 project will go ahead. And the amp will be built.So bring it!

U have been served.

_________________
Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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PostPosted: 08 Oct 2011, 13:50 
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mwhouston wrote:
U have been served.
And, of course sir, I accept the challenge.

However, that being said, my son recently chastised me for my flat build techniques arguing that I should try going vertical for my next amp. So the case for this 807 amp may well be a more complicated undertaking. I was thinking of a vertical mix of white oak, and black walnut with some purple heart inlay. There will also be bias meters for the 807s. Obviously this may take a little longer than normal.

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Matt
It's all about the Glass!
http://www.CascadeTubes.com
Cascade Tubes Blog


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PostPosted: 08 Oct 2011, 19:16 
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Matt if you use a power tranni which will work with 240/120V mains then we have a chance of swapping amps. Unfortunately the little buggers are heavy so any shipping is going to be expensive. Anyhow I suppose we should get them built and see where it goes from there. Exciting isn't it.

_________________
Projects:“Salt Cellar” - Mono 807 triode integrated amp |
"Rosso" - E88CC SRPP preamp | ”Salt Cellar II” - 6EM7 mono wine box triode amp | “MWH” - 1920s UX-171A preamp |


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 Profile  
 
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