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stolbovoy 10th March 2008 01:44 PM

KrellClone KSA100-MKII 1000VA toroidal transformer for dual mono GB
2 Attachment(s)
As discussed in the original Krell KSA-100mkII thread (, I decided to start GB for toroidal transformers for the project to get better pricing from Toroid Corporation of Maryland ( This is transformer for dual mono version of the amplifier.
Transformer should have electrostatic and magnetic shield and have following windings:
Primaries: 110/120 – dual for 110, 120 220 and 240V mains
2*38V*12A(under full 12A load)/39.5V(no load) – output stage
2*10V*12A(under full 12A load)/10.5V(no load) – output stage extra, for those who’d like to experiment with LC power supply, drive higher impedance load, etc
2*65V*0.8A – “main board” – everything else in audio path (LTP - driver), for regulated PSU
2*15V*0.25A - for protection, soft start windings, etc

I didn’t get final quote, but I’d expect prices in $220 range per transformer (shipment is extra) if 10 or more ordered.

Preliminary specs without 4 extra windings and tap on primaries attached. I'm going to send request for final quote tomorrow morning (3/11/2008 EST time).

I'd like to place an order no later then the end of the next week.

stolbovoy 10th March 2008 01:52 PM

There is a concern that 65V is a bit too high for main board regulated supply, but I decided to keep more options open in exchange of bigger PSU heatsinks. This is open for discussion, may be it is worth to make a tap at 55/10V

Flodstroem 10th March 2008 09:50 PM

Also for KRELL Clone KSA-50 mkII
;) Be aware of this transformer is well suited for the KSA-50 clone project too ;)

You have the opportunity to wire it for approx. 29V AC secondary and a universal mains voltage of 110, 120 220, 230 and 240V primary.

This transformer, 1.2 kVA for to be correct is perfect for a 2 ch. stereo amp, but it could also serve as a mains transformer for a 4 ch. bi-wired speaker system (active crossover) if speaker has 8 ohms impedance. Otherwise you will need two transformers for to bi-wire 4 ohms speaker (2 x 2 channels). :rolleyes:

Regards :cool:

stolbovoy 12th March 2008 03:47 PM

Request for final quotes sent

stolbovoy 19th March 2008 05:59 PM

2 Attachment(s)
Final quotes from


Pricing, Terms and Conditions
Prices are FOB, Salisbury, MD. Terms and conditions as per enclosed form 228 apply unless otherwise agreed upon in writing. Our product warranty is 36 months as per paragraph 8 in the enclosed form 228. Quote is good for 60 days

Quantity- Price ($) each
2- $410.43
5- $302.32
10- $260.97

Delivery time: 1-5 prototypes can ship in 2-3 weeks or less after approval of data sheet. Production volume as agreed upon, shipping currently 4-5 weeks or less after prototype approval, depending on quantity ordered.
Auxiliary secondary windings are 10V*0.8A instead of 15V - it seams cheaper to use thicker gauge, that change wire. 10VAC will give unregulated 12VDC each.

I'd like to make an order by Friday, March 21st.

stolbovoy 19th March 2008 07:14 PM

They forgot magnetic shield, so price will be little bit higher

pollypocket 19th March 2008 08:00 PM


Are you taking orders here or on the main page?


stolbovoy 19th March 2008 08:20 PM


Originally posted by pollypocket

Are you taking orders here or on the main page?


Here is more appropriate place for this. How many do you need?

I just talked with Ming (engineer who designed transformer) - the prices include magnetic shield, so quotes are final.

pollypocket 19th March 2008 08:46 PM

What price level are we at? Assuming we will meet the 10 quantity price level, I am in for 2. Are you accepting Paypal?



stolbovoy 19th March 2008 08:48 PM

Right now we are at 4, but I just got final quote

I'm pretty shure it will be at least 5+, not sure about 10+

PayPal is preferred method of payment (+3%)

stolbovoy - 2
pollypocket -2

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