La Figaro 339
Mar 2, 2021 at 4:07 PM Post #6,316 of 6,903
I wonder what other 6080 tube amps afficionados are loving the Bendix..
You can use them in the DV, GOTL amps, Feliks amps to name a few
 
Mar 2, 2021 at 4:24 PM Post #6,318 of 6,903
@L0rdGwyn good news on the 339i front...virtual center tap works on 339i too.

@telecaster Did you document the process with pics so we could try? You mentioned Fender amp...is that where your user name comes from?

Glad to hear it worked out @telecaster , if there is still some residual hum, elevating the heaters should remove it completely. You will find the center tap is already done in most amplifiers, grounding one half of the heaters is not the recommended approach.

BTW @Galapac , Mouser finally got me my package, just need to put in this new reservoir cap, upgrade the heatsink on the regulator power MOSFET, and replace the gyrator caps and your hot rodded DarkVoice should be done. Will get to it Thursday or Friday.

It sounds very good with a nice 6SN7 and a Western Electric 421A, so I hope you have a 421A or 5998 lying around! Can also use 6J5 with an adapter. I will be very curious to know how it compares to the La Figaro 339i.

IMAG3127-2.jpg
 
Mar 2, 2021 at 4:34 PM Post #6,320 of 6,903
Glad to hear it worked out @telecaster , if there is still some residual hum, elevating the heaters should remove it completely. You will find the center tap is already done in most amplifiers, grounding one half of the heaters is not the recommended approach.

BTW @Galapac , Mouser finally got me my package, just need to put in this new reservoir cap, upgrade the heatsink on the regulator power MOSFET, and replace the gyrator caps and your hot rodded DarkVoice should be done. Will get to it Thursday or Friday.

It sounds very good with a nice 6SN7 and a Western Electric 421A, so I hope you have a 421A or 5998 lying around! Can also use 6J5 with an adapter. I will be very curious to know how it compares to the La Figaro 339i.

IMAG3127-2.jpg

You got me interested in trying the gyrator to load the 6j5!😃😃😜

Thanks L0rdGwyn!

Yes there is a tiny bit of hum left so I will try the elevation!
 
Mar 2, 2021 at 4:39 PM Post #6,321 of 6,903
@L0rdGwyn good news on the 339i front...virtual center tap works on 339i too.

@telecaster Did you document the process with pics so we could try? You mentioned Fender amp...is that where your user name comes from?
Oh it was very easy, i can post a photo tomorrow to show how it's done.

First empty the power left in capacitors on both sides with a resistors.
It will really hurt you or tickle you at best If you don't.
Then...
Just need to wire two 100ohm resistors to both heaters, ground the center tap, and at the drivers sockets you must separate the ground from the heaters. That's it 😉.
I did it on my little guitar amp just like this.

Oh yes i play the telecaster, i have a bunch!😁
 
Mar 2, 2021 at 4:41 PM Post #6,322 of 6,903
Glad to hear it worked out @telecaster , if there is still some residual hum, elevating the heaters should remove it completely. You will find the center tap is already done in most amplifiers, grounding one half of the heaters is not the recommended approach.

BTW @Galapac , Mouser finally got me my package, just need to put in this new reservoir cap, upgrade the heatsink on the regulator power MOSFET, and replace the gyrator caps and your hot rodded DarkVoice should be done. Will get to it Thursday or Friday.

It sounds very good with a nice 6SN7 and a Western Electric 421A, so I hope you have a 421A or 5998 lying around! Can also use 6J5 with an adapter. I will be very curious to know how it compares to the La Figaro 339i.

I think I got one of those...I also have some decent, non GE 6SN7s/5692/6J5GT hanging around. I’m pumped to try it out. Will be like a brand new amp! I have a stock DV that I use with my turntable so I will probably compare those first with my ZMFs, then swap the stock out to use the modded DV with the turn table going forward. They will need to pry it from my dead arms to sell it, it is now legendary thanks to you!
F302F549-4A36-4221-8B06-BE3BA06705F4.jpeg
 
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Mar 2, 2021 at 4:52 PM Post #6,323 of 6,903
I think I got one of those...I also have some decent, non GE 6SN7s/5692/6J5GT hanging around. I’m pumped to try it out. Will be like a brand new amp! I have a stock DV that I use with my turntable so I will probably compare those first with my ZMFs, then swap the stock out to use the modded DV with the turn table going forward. They will need to pry it from my dead arms to sell it, it is now legendary thanks to you!
F302F549-4A36-4221-8B06-BE3BA06705F4.jpeg

Nice! Those should do the job :) well I do hope it satisfies. It really isn't a DarkVoice anymore, it is my take on the popular direct-coupled 6080 OTL crushed into a DarkVoice chassis LOL. Like I said, I might do an "expanded" build in a custom chassis at some point to allow for some other circuit changes, but no timeline, I need to finish my monster 801A amplifier...I think I've maximized what can be done inside the DarkVoice though. Will do another stress test on Thursday or Friday with the new MOSFET heatsink, it was too toasty for comfort with the original, new one should be better.
 
Mar 2, 2021 at 4:57 PM Post #6,324 of 6,903
You got me interested in trying the gyrator to load the 6j5!😃😃😜

Thanks L0rdGwyn!

Yes there is a tiny bit of hum left so I will try the elevation!

Since the La Figaro circuit is more or less the same as the DarkVoice with a few changes, pretty much all of the mods I made to the DarkVoice could be applied to the La Figaro, you could try a gyrator load on the driver tube, or a constant current source. Gyrator regulates the plate voltage though, which is helpful for direct-coupling.

Only issue is the B+. It is around 150VDC in the DarkVoice. I regulated the power supply to get a higher B+, 183VDC, by removing all of the RC filters in the supply, which gave more headroom for the gyrator load. Not sure if the La Figaro also has a 150VDC B+, but if so, an active load could work but not a lot of voltage headroom depending on the bias point.
 
Mar 2, 2021 at 5:17 PM Post #6,325 of 6,903
Since the La Figaro circuit is more or less the same as the DarkVoice with a few changes, pretty much all of the mods I made to the DarkVoice could be applied to the La Figaro, you could try a gyrator load on the driver tube, or a constant current source. Gyrator regulates the plate voltage though, which is helpful for direct-coupling.

Only issue is the B+. It is around 150VDC in the DarkVoice. I regulated the power supply to get a higher B+, 183VDC, by removing all of the RC filters in the supply, which gave more headroom for the gyrator load. Not sure if the La Figaro also has a 150VDC B+, but if so, an active load could work but not a lot of voltage headroom depending on the bias point.
I think I need to do my homework before modding the 339. I use different drivers (6J5, EF86, 6SJ7) so a fixed bias might not be ideal for me! I might roam in your DIY thread and ask you questions though if you don't mind ^^
 
Mar 2, 2021 at 5:21 PM Post #6,326 of 6,903
@L0rdGwyn good news on the 339i front...virtual center tap works on 339i too.

@telecaster Did you document the process with pics so we could try? You mentioned Fender amp...is that where your user name comes from?

Here is my cheap chinese amp (True Blood 5F1)! It was wired point to point so it's kind of WOW when you consider I bought it only 300€ new! I just changed the speaker and rewired the rectifier from chinese 6Z4 to NOS Tungsol 6X4, and score!
I slipped in a Telefunken ECC88 and a RCA 6V6 and now it's really a great amp!

You can see the virtual center tap on the far right. The black wire (ground) was connected to one side of the heater on the 12AX7 socket. I just desoldered it and soldered both little blue 100 ohm resistors to it!

Now I just need to add a variable negative feedback pot to this and it's a great little amp!

50997976391_cbacac1276_o.jpg
 
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Mar 2, 2021 at 8:44 PM Post #6,327 of 6,903
Mar 2, 2021 at 9:34 PM Post #6,328 of 6,903
由于拉菲加罗电路与黑暗之声的电路大致相同,只要有一些变化,我给黑暗之声做的所有mods都可以应用于拉菲加罗,你可以尝试驱动管上的旋转器负载,或者恒流源.回转器调节平板电压,这对直接耦合是很有帮助的.

唯一的问题是B+.这是大约150 VDC在黑暗之声.我调整电源,以获得一个更高的B+,183个VDC,通过删除电源中的所有RC滤波器,这为回转器的负载提供了更大的空间。不确定拉菲加罗是否也有一个150 VDC B+,但如果是,一个有源负载可以工作,但没有多少电压高度空间取决于偏置点。

Since the La Figaro circuit is more or less the same as the DarkVoice with a few changes, pretty much all of the mods I made to the DarkVoice could be applied to the La Figaro, you could try a gyrator load on the driver tube, or a constant current source. Gyrator regulates the plate voltage though, which is helpful for direct-coupling.

Only issue is the B+. It is around 150VDC in the DarkVoice. I regulated the power supply to get a higher B+, 183VDC, by removing all of the RC filters in the supply, which gave more headroom for the gyrator load. Not sure if the La Figaro also has a 150VDC B+, but if so, an active load could work but not a lot of voltage headroom depending on the bias point.
Is the same designer, black voice because of the separation of the new design Figaro 339.
Http://www.diybuy.net/thread-224221-1-1.html
 
Mar 2, 2021 at 11:00 PM Post #6,329 of 6,903
Is the same designer, black voice because of the separation of the new design Figaro 339.
Http://www.diybuy.net/thread-224221-1-1.html
What I think @xmdkq is trying to say is the he is one of the original designers of the Dark Voice, but due to disagreements in the original company, they parted ways and he started a new company, Chengdu Yuqin Audio and Video Studio, which makes the La Figaro, and other products.

我认为 @xmdkq 想要说的是,他是《黑暗之声》的原始设计师之一,但是由于与原始公司的分歧,他们分道扬and,于是他成立了一家新公司,成都玉琴音像工作室,制造La Figaro和其他产品。

@xmdkq - Do you have a link or page to your other products?
@xmdkq - 您是否有指向其他产品的链接或页面?
 
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