[guest1632]

Hi all,

I'll repost this. Maybe, I'll get some answers. I am looking at both the GGP (Grounded Grid Preamp) from Transcendentsound versus the one from Analog Metric. The major difference between the two is that the Analog Metric uses only one transformer with the three taps for the 12.6V and the Plus and Minus 200V.

So if I only used that one transformer versus three which TS uses, would I hear any real difference? Thanks for the info.

Ray Bronk

[Folsom]

What is each transformer being used for? In my opinion if you could separate each channel of Left and Right (what is the third?) especially with grounding, GO FOR IT.

[guest1632]

What is each transformer being used for? In my opinion if you could separate each channel of Left and Right (what is the third?) especially with grounding, GO FOR IT.

Hi, Each transformer handles different stuff. One is the filament supply, the other two are the Plus and minus 200 Volt supplies. I was also trying to figure out if I used this CCS on the filament supply and eliminating the Minus 200 V supply. What advantage other than the removal of a high voltage supply would I gain?

It's all in the planning stages at this moment.

Ray Bronk

[Folsom]

I think these questions are better for someone else.

[guest1632]

I think these questions are better for someone else.

Hi, Well, then, let's see who will step up and answer my question. Are we talking theoretically or for real here.

Ray Bronk

[JohnR]

My (vague) recollection is that Bruce Rozenbilt specs the transformers in his published designs for easy off-the-shelf availability. That's why sometimes more are used than would be necessary if custom winding were an option.

It's not entirely clear to me what the question is - you are building a preamp from scratch? I personally would try and go for a design that allowed for a single off-the-shelf transformer for ease of building and chassis work.

[sts9fan]

I think for my Aikido I am gonna split he difference.  I am will get on transformer for B+,Rectifier heater and power my relay volume control. Sop that wpould be 540VCT and dual 5v filaments.  Then a separate 6.3V @5A for the heater of the tubes.  From what I have read separate transformers puts less stress on the core of the power transformer and isolates noise. 

[BradJudy]

It's not entirely clear to me what the question is - you are building a preamp from scratch? I personally would try and go for a design that allowed for a single off-the-shelf transformer for ease of building and chassis work.

I think he's trying to pick a kit.  In the case of the Transcendant Sound one, it includes everything (case, jacks, etc), so ease of build shouldn't be an issue. 

Personally, I'd order from Transcendant since this is the designer's company and I would want my $$ to go to him.  My second choice would be a total DIY (no kit) using the information in his book. 

Analog Metric might be cheaper, but I doubt the designer gets his dues that way. 

[Bill Baker]

It depends more on the quality of the transformers. If a single transformer is of better quality than even two or three separate transformers, that would be the best route.

 Many companies have unique transformers designed for them for each application. We use a separate transformer for the B+ voltage and filament supply in many of our products where some of our other designs use a single custom designed transformers with high quality electrostatic shielding.

If using a single transformer, having one with electrostatic shielding would provide the best results. A lesser cost version would use split bobbin nonconcentric winding. These are your usual off the shelf pieces.

 Separate transformers would be best in my opinion if lesser quality pieces are being used. Less noise.

 Just my two cents.

[guest1632]

It depends more on the quality of the transformers. If a single transformer is of better quality than even two or three separate transformers, that would be the best route.

 Many companies have unique transformers designed for them for each application. We use a separate transformer for the B+ voltage and filament supply in many of our products where some of our other designs use a single custom designed transformers with high quality electrostatic shielding.

If using a single transformer, having one with electrostatic shielding would provide the best results. A lesser cost version would use split bobbin nonconcentric winding. These are your usual off the shelf pieces.

 Separate transformers would be best in my opinion if lesser quality pieces are being used. Less noise.

 Just my two cents.

Thanks Bill, Brad Judy and John R. I don't have the bucks to just go and buy either of the two kits. So I will have to get the parts piece at a time. That sucks, but this is life. Anyway, one other question.

There is this Constant Current Source (CCS) that I've read about that is supposed to eliminate the need for this Minus 200V supply. I don't know the exact particulars on it, but it uses a LM317 regulator and a few resistors. Any thought on that item. Again, thank you for your knowledge. Nothing here is cust in stone. So I am interested in just learning the hows and whys before I set out to do.

Ray Bronk

[BillB]

Why not just build a topology that does not require a B-?