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AUDIO FORUMS >> Classifieds >> ~Glasphone~ preamp
https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1733888339

Message started by 4krow on 12/11/24 at 03:38:59

Title: ~Glasphone~ preamp
Post by 4krow on 12/11/24 at 03:38:59

Been busy this year building a couple of preamps. I have got one for sale that I am listening to tonight. I call it the Glasphone to give it a 30's name that might have existed back in the day. I really like the wood designs of that era, so I built one. Went with the real stuff, not Chinese fakes. The knobs are the real thing. Now of course, all of the internals are new and assembled by me. I will add more info in the near future, but here are some photos to give an idea of what this is all about. ~Price is $1,500~

Title: Re: ~Glasphone~ preamp
Post by 4krow on 12/11/24 at 04:11:55

This was the basic layout when I started. One of the most important aspects of my builds is absolute strength and integrity of the mechanical structure (chassis) for the physical support of boards and components. Shown here is the 1/2 Corian blocks under the power supply. The front panel is supported not just by the sheet metal top and bottom, but by an angle iron brace for each, making this exceptional in its mechanical structure. It is just part of what I do.

Important features are:
1) 3 inputs
2) 2 outputs
3) 1 feedthrough output (unaffected by volume/balance
4) Dedicated headphone amp with its own volume control
5) Audio Note balance control that has little effect on sound. Yup, this is an overlooked feature these days, unless a unit has separate mono volume controls.

image uploader

Title: Re: ~Glasphone~ preamp
Post by Crazy Bill the Eel Killer on 12/11/24 at 13:04:19

Curious as to the source and make-up of the circuit boards.

Title: Re: ~Glasphone~ preamp
Post by Crazy Bill the Eel Killer on 12/11/24 at 13:10:02

Disregard, Just found the info in the DIY section. Nice work.

Title: Re: ~Glasphone~ preamp
Post by 4krow on 12/11/24 at 17:30:52

It is only right that I catch you guys up in this ad as to who/what/why is answered. I really enjoy building quality units. I used to do woodworking but have had an interest in audio since I was a kid. So, these one of a kind products are the result. Fortunately for you, my name isn't famous and so I don't charge much to these since it is for the love of it all. I do however, have to replenish my parts inventory, hence the modest charge for these one off units. Ok, here is the breakdown of the kits/parts:
1) John Broskie of GlassWare Audio designed the power supply used here along with preamp board which he calls the 'SRPP+'. It uses two 12AU7 tubes run at 200 VDC on the plate. Go to GlassWare Audio and read more there. While your at it, you can get an idea of what the ASR site has to say about this circuit as well.
2) The power supply uses two separate transformers. One for high voltage, one for heater voltage. They are both toroid types. The power supply board itself is very heavy duty by GlassWare. The model is the PS21. It handles both the high and low voltages. As it turns out, there are two 12 volt outputs and the SRPP takes only one, so, that is where I got the idea of adding a separate headphone amp.
3) The headphone amp is designed by Pete Millett. Pete comes from long ago with a background in HAM radio (remember those?). He is a well respected engineer whose products/builds can be found at DIY Audio. You will notice that the headphone board (blue board) uses a weird little square shaped tube. It is called the SP1 tube, and was originally used in products by Korg. People like Pete M and Nelson Pass took a great interest in designing circuits for this tube. Simple circuits with surprisingly good sound. Again, go to DIY Audio and look for the B1K NuTube preamp. That is a start.
4) I have gone out of my way for almost every part in this build to be way above the norm in quality and ruggedness. It is just the way that II think. Reminds me of the Decware products that I have owned in the past.
Ok, enough for this. I'm tired of typing. Go ahead, ask questions.

Title: Re: ~Glasphone~ preamp
Post by 4krow on 12/11/24 at 17:51:34

This will be the last post for this classified ad unless I am answering specific questions from buyer.

~SOUND~

I agree that this is where it all rests in the end. It is also fairly difficult to described outside of my system and room and even musical choice. As close as I can come for what I am experiencing. Great bass because it is well defined. That is a big thing to me. The tube midrange that I have come to love over the decades. Just natural and no bite, unless it is in the recording. How about anti-digital sound as we were subjected to it back in the beginning of consumer digital? I know that Broskie designs have an incredible treble that is very open but frankly I do not hear it like I used to so I am skipping that part. This preamp has a lot of drive and yet, I do not find it aggressive sounding.
One final thought. I will work with you for shipping and believe me, I pack well beyond what most people seem to think is required. It took months for me to build this, so it is my baby. The last thing that either one of us wants is trouble before the damned thing even makes it to you!

Title: Re: ~Glasphone~ preamp
Post by 4krow on 12/24/24 at 18:10:15

FWIW, I have relisted this unit today at US Audio Mart. As stated before price is negotiable.