Home » Audio » Group Build » Need favorite 12B4 for Guinevere line stage recommendations?
possible source for DN2540N5 transistors [message #31509 is a reply to message #31508] Wed, 30 November 2005 21:43 Go to previous messageGo to next message
MQracing is currently offline  MQracing
Messages: 220
Registered: May 2009
Master

Hi Norris:

I got a bunch from Kevin at K&K audio (the US lundahl importers). Give kevin a shout or email him. If you get stuck and just need a few I may have some I could part with.

msl

Re: Need favorite 12B4 for Guinevere line stage recommendations? [message #31510 is a reply to message #31507] Thu, 01 December 2005 05:39 Go to previous messageGo to next message
Manualblock is currently offline  Manualblock
Messages: 4973
Registered: May 2009
Illuminati (13th Degree)
Nice. Thats a good explanation and I will file it with my rules of construction notebook.
I have printed out another copy of the trasnsformer article. It's 8 pages and I can snail mail it to you if you want. Let me know.

another source... [message #31511 is a reply to message #31508] Thu, 01 December 2005 10:30 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
Hey-Hey!!!,
I am getting low on them myself. I would split an order of 50 with you, or add a few folks and we can split up an order of 100. They are quite useful. I think K&K sells them for ~$3.50 each, which is a reasonable One or Two-up on a low volume item.
cheers,
Douglas

availability of DN2540N5 [message #31512 is a reply to message #31508] Thu, 01 December 2005 12:24 Go to previous messageGo to next message
MQracing is currently offline  MQracing
Messages: 220
Registered: May 2009
Master
Hi Norris:

I was on the horn with Kevin this morning to follow up and see if he still had this part number in stock and he said you had emailed him and that he does have stock on this part number...

so... then I spent some mullah with Kevin purchasing a seiden 23 position switch that we're going to use in a preamp that Kevin and I have been designing together.

can I send ya the bill :=))

cheers and best of,

msl



Re: Need favorite 12B4 for Guinevere line stage recommendations? [message #31513 is a reply to message #31510] Thu, 01 December 2005 14:47 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
that would be great. send me your email again, as I buried it somewhere I can't find right now. I'll send you the mailing address, along with my thanks for sharing information. I can scan it to pdf and return it to you if you wish.
cheers,
Douglas

Power supply isolation [message #31514 is a reply to message #31508] Thu, 01 December 2005 14:57 Go to previous messageGo to next message
PakProtector is currently offline  PakProtector
Messages: 935
Registered: May 2009
Illuminati (2nd Degree)
Hey-Hey!!!,
The active load does isolate the amplifier stge from the PS. Some have suggested a minimum reactance( both C and L ). Like a few uF of capacitance, and that's all...I have personally liked the result of a good L-C stage. 20 Hy and 100 uF of motor run style Oilers.

WHen used as a mu follower, the PS is again included in the PS, but still to a large degree isolated...so a High performance PS is still a good idea, and contributes in a positive way to the sound.

On the detail construction of the CCS, there is some benefit to building with a few batteries and the R-C filter on the gate. ONe needs to protect the +/- 20 volt gate-source voltage maximum with a cathode-cathode Zener clamp. The batteries will prefer a low leakage version BZX79C18 would be my preference, though BZX55C18 is not far behind...:)
cheers,
Douglas

No bills, Please! [message #31515 is a reply to message #31512] Thu, 01 December 2005 17:40 Go to previous messageGo to next message
Norris Wilson is currently offline  Norris Wilson
Messages: 361
Registered: May 2009
Grand Master
Hi Michael,
Thanks for checking with Kevin about the transistors.
I am going to order some from him tomorrow.
What type of line stage are you in the process of building, details?
Curious minds want to know.
Thanks
Norris Wilson


Re: No bills, Please! [message #31516 is a reply to message #31515] Thu, 01 December 2005 20:18 Go to previous messageGo to next message
MQracing is currently offline  MQracing
Messages: 220
Registered: May 2009
Master
Hi Norris:

you wrote:

::::Thanks for checking with Kevin about the transistors.
I am going to order some from him tomorrow.::::

Glad I could assist. Kevin's a good guy and I've enjoyed working with
him on some of our new products.

::::What type of line stage are you in the process of building, details?
Curious minds want to know::;;.


awe... it's a bit premature for us to release many specific design details at this juncture. Here are some of the directions and details of what we are developing... all of the following subject to the rigors of an ongoing R&D program...

It's a line level only preamp with a commercially unique circuit architecture. It uses two tubes. It has a rectifier tube. Has independent power supplies for each channel. It employs 3 pieces of signal carrying iron per unit. The output impedance is less than 100 ohms with a correspondingly large current drive capacity. It has a transformer buffered input stage. It can accomadate bal signal transmission (i.e., xlr). It can also accomadate single ended signal transmissions (i.e., rca). It employs authentic Peerless (tm) iron in critical component areas. A means is provided for attenuation of the input signal. It will accomadate multiple input sources and most likely have monitoring capabilities. Multiple core materials (mu metal and nano crystalline c-cores) are planned as customer specified options. Power supply filter features a very large >100 henry custom made by MagneQuest choke for each channel.

Though my description is somewhat vague... I hope it gives you some idea of where we might be headed with this preamp. As your aware... since we are a magnetics producer (including the Peerless (tm) and MagneQuest (tm) brand names) our preamp is rich in iron. But iron smartly deployed if I may be so immodest.

As an earnest stab at the state of the art... this preamp is not going to be cheap which only reflects our commitment to build the best we can... i.e., we are not interested in desgining and building to an arbitrary price point derived by a marketing study. Our preamp (code named "Abbie") will only be available as a finished product. It is one of three finished products that we currently have under development. We anticipate availability late in the first quarter of 2006.

Our other two undertakings are a transformer based passive preamp (much, much less mullah)and a dedicated stand alone moving coil step up transformer.

in the meantime... get your irons hot and build that Guinevere... hope you have some fun and experience some rewarding tunes with your new self-built preamp.


cheers,

msl




Re: No bills, Please! [message #31517 is a reply to message #31516] Thu, 01 December 2005 20:54 Go to previous messageGo to next message
Norris Wilson is currently offline  Norris Wilson
Messages: 361
Registered: May 2009
Grand Master
Thanks Michael for the preview description of your new joint venture with Kevin. This line stage sounds like it will be one fine piece of iron rich realestate.
I hope you will keep us abreast as the developement comes along.
Your short discription is detailed enough to realise that this line stage will be diverse and elegant.
I am looking forward to seeing the finished product.
Keep up the good work. And I will keep the solder going while I learn and enjoy this hobby.
Norris Wilson

You and Kevin,working together, that's neat. [message #31520 is a reply to message #31517] Fri, 02 December 2005 20:10 Go to previous messageGo to previous message
2wo is currently offline  2wo
Messages: 44
Registered: May 2009
Baron
I would have thought you would be ’fierce Competitors’ rather than ‘ Co-conspirators’…John

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